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Click for overall list of YEAR 2010 (mixed, earlier than 2009 - go by the specialty field) |
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(Year) - Authors - Title -
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(2009) Ali, A. Nonlinear multivariate rainfall-stage model for large wetland systems. Journal of Hydrology 374(3-4), 338-350. |
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ABSTRACT
Wetland restoration is often measured by how close the spatial and temporal water level (stage) patterns are to the pre-drainage conditions. Driven by rainfall, such multivariate conditions are governed by nonstationary, nonlinear, and nonGaussian processes and are often simulated by physically based distributed models which are difficult to run in real time due to extensive data requirements. The objective of this study is to provide the wetland restorationists with a real time rainfall-stage modeling tool of simpler input structure and capability to recognize the wetland system complexity. A dynamic multivariate Nonlinear AutoRegressive network with eXogenous inputs (NARX) combined with Principal Component Analysis (PCA) was developed. An implementation procedure was proposed and an application to Florida Everglade's wetland systems was presented. Inputs to the model are time lagged rainfall, evapotranspiration and previously simulated stages. Data locations, preliminary time lag selection, spatial and temporal nonstationarity are identified through exploratory data analysis. PCA was used to eliminate input variable interdependence and to reduce the problem dimensions by more than 90% while retaining more than 80% of the process variance. A structured approach to select optimal time lags and network parameters was provided. NARX model results were compared to those of the linear Multivariate AutoRegressive model with eXogenous inputs. While one step ahead prediction shows comparable results, recursive prediction by NARX is far more superior to that of the linear model. Also, NARX testing under drastically different climatic conditions from those used in the development demonstrates a very good and robust performance. Driven by net rainfall, NARX exhibited robust stage prediction with an overall Efficiency Coefficient of 88%, Mean Square Error less than 0.004 m(2), a standard error less than 0.06 m, a bias close to zero and normal probability plots show that the errors are close to normal distributions.
KEYWORDS: Everglades; Wetland restoration; Multivariate time series analysis; Nonlinear model; Rainfall water-level model; Rainfall Driven Operations artificial neural-network; runoff model |
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(2009) Anonymous. MS aids restoration of Florida Everglades. Trac-Trends in Analytical Chemistry 28(5), XIII-XIII. |
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ABSTRACT (none)
KEYWORDS: Everglades restoration |
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(2009) Balentine, K.M., Pratt, P.D., Dray, F.A., Rayamajhi, M.B. and Center, T.D. Geographic Distribution and Regional Impacts of Oxyops vitiosa (Coleoptera: Curculionidae) and Boreioglycaspis melaleucae (Hemiptera: Psyllidae), Biological Control Agents of the Invasive Tree Melaleuca quinquenervia. Environmental Entomology 38(4), 1145-1154. |
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ABSTRACT
The invasive tree Melaleuca quinquenervia (Cav.) Blake is widely distributed throughout peninsular Florida and poses a significant threat to species diversity in the wetland systems of the Everglades. Mitigation of this threat includes the areawide release campaign of the biological control agents Oxyops vitiosa Pascoe and Boreioglycaspis melaleucae Moore. We summarize the results of this release effort and quantify the resulting geographic distribution of the herbivores as well as their regional impact on the target weed. A combined total of 3.3 million individual Melaleuca biological control agents have been redistributed to 407 locations and among 15 Florida counties. Surveys of the invaded area indicate that the geographic distribution of O. vitiosa encompasses 71% of the Melaleuca infestation. Although released 5 yr later, the distribution of B. melaleuca is slightly greater than its predecessor, with a range including 78% of the sampled Melaleuca stands. Melaleuca stands outside both biological control agents' distributions occurred primarily in the northern extremes of the tree's range. Strong positive association between herbivore species was observed, with the same density of both species occurring in 162 stands and no evidence of interspecific competition. Soil type also influenced the incidence of biological control agents and the distribution of their impacts. The odds of encountering O. vitiosa or B. melaleucae in cells dominated by sandy soils were 2.2 and 2.9 times more likely than those predominated by organically rich soils. As a result, a greater level of damage from both herbivores was observed for stands growing on sandy versus organic-rich soils.
KEYWORDS:herbivory; invasive species; dispersal; weed biological control;
postrelease evaluation
field colonization; australian weevil; cav. blake,s.t.; south florida;
united-states; host-range; herbivory; insects; competition; myrtaceae |
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(2009) Barr, J.G., Fuentes, J.D., Engel, V. and Zieman, J.C. Physiological responses of red mangroves to the climate in the Florida Everglades. Journal of Geophysical Research-Biogeosciences 114, 114, G02008, doi:10.1029/2008JG000843.
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ABSTRACT
This manuscript reports the findings of physiological studies of red mangrove (Rhizophora mangle L.) conducted from June to August 2001 and from May to June 2003 in the Florida Everglades. In situ physiological measurements were made using environmentally controlled gas exchange systems. The field investigations were carried out to define how regional climate constrains mangrove physiology and ecosystem carbon assimilation. In addition, maximum carboxylation and photosynthetic active radiation (PAR) limited carbon assimilation capacities were investigated during the summer season to evaluate whether ecophysiological models developed for mesophyte plant species can be applied to mangroves. Under summertime conditions in the Florida Everglades, maximum foliar carbon dioxide (CO2) assimilation rates reached 18 mmol CO2 m(-2) s(-1). Peak molar stomatal conductance to water vapor (H2O) diffusion reached 300 mmol H2O m(-2) s(-1). Maximum carboxylation and PAR-limited carbon assimilation rates at the foliage temperature of 30 degrees C attained 76.1 +/- 23.4 mu mol CO2 m(-2) s(-1) and 128.1 +/- 32.9 mmol (e(-)) m(-2) s(-1), respectively. Environmental stressors such as the presence of hypersaline conditions and high solar irradiance loading (> 500 W m(-2) or > 1000 mu moles of photons m(-2) s(-1) of PAR) imposed sharp reductions in carbon assimilation rates and suppressed stomatal conductance. On the basis of both field observations and model analyses, it is also concluded that existing ecophysiological models need to be modified to consider the influences of hypersaline and high radiational loadings on the physiological responses of red mangroves.
KEYWORDS:gas-exchange characteristics; rhizophora-mangle-l; water-use
efficiency; field conditions; carbon gain; photosynthesis; salinity;
forest; soil; conductance |
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(2009) Beckage, B., Platt, W.J. and Gross, L.J. Vegetation, Fire, and Feedbacks: A Disturbance-Mediated Model of Savannas.
American Naturalist 174(6), 805-818. |
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ABSTRACT
Savanna models that are based on recurrent disturbances such as fire result in nonequilibrium savannas, but these models rarely incorporate vegetation feedbacks on fire frequency or include more than two states (grasses and trees). We develop a disturbance model that includes vegetation-fire feedbacks, using a system of differential equations to represent three main components of savannas: grasses, fire-tolerant savanna trees, and fire-intolerant forest trees. We investigate the stability of savannas in the presence of positive feedbacks of fire frequency with (1) grasses, (2) savanna trees, and (3) grasses and savanna trees together while also allowing for negative feedbacks of forest trees on fire frequency. We find that positive feedbacks between fire frequency and savanna trees, alone or together with grasses, can stabilize savannas, blocking the conversion of savannas to forests. Negative feedbacks of forest trees on fire frequency shift the range of parameter space that supports savannas, but they do not generally alter our results. We propose that pyrogenic trees that modify characteristics of fire regimes are ecosystem engineers that facilitate the persistence of savannas, generating both threshold fire frequencies with rapid changes in community composition when these thresholds are crossed and hystereses with bistable community states.
KEYWORDS:disturbance; ecosystem engineer; fire; forest; grassland; savanna
tree-grass coexistence; nino southern-oscillation; longleaf pine
savannas; ecosystem engineers; tropical savanna; natural disturbances;
florida-everglades; brazilian cerrado; exotic grasses; climate-change |
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(2009) Belmont, M.A., White, J.R. and Reddy, K.R. Phosphorus Sorption and Potential Phosphorus Storage in Sediments of Lake Istokpoga and the Upper Chain of Lakes, Florida, USA. Journal of Environmental Quality 38(3), 987-996. |
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ABSTRACT
Phosphorus (P) can be an important nutrient in regulating primary productivity in lakes. The ability of lake sediments to retain P from external sources depends on the physiochemical characteristics of the sediment. To assess the P dynamics in Lake Istokpoga and the upper chain of lakes that drain into Lake Okeechobee, Florida, USA, sorption properties of batch sediment samples for Lakes Tohopekaliga, Cypress, Hatchineha, Kissimmee, and Istokpoga were characterized under aerobic and anaerobic conditions. Langmuir model parameters fit the experimental data well (in general, r(2) > 0.70). There were strong correlations between P sorption and total C, total P, Ca, Mg, Fe, and Al (r = 0.83-0.97). Equilibrium P concentration values ranged between 0.001 and 0.192 mg L-1 for aerobic conditions. A single-point isotherm (initial concentration, 5 mg L-1) was found for a wide range of sediment types, which allows estimation of the maximum potential sorption (S) as 1.7 times the sorption (S-max = 1.7 S-s). Results suggest that although these sediments have high P sorption capacities, the lake sediments may release P into the water column by desorption under aerobic conditions if water-column P concentrations are low enough (<0.036 mg L-1 for Lake Tohopekaliga and <0.003-0.027 mg L-1 for the other four lakes). Current watershed management strategies must balance efforts to reduce P inputs into the lakes from point and nonpoint sources against lowering the water-column P concentration to such a low level that the lake sediments become a source of P to downstream Lake Okeechobee.
KEYWORDS:wetland soils; phosphate adsorption; subtropical lake; water;
everglades; retention; shallow; okeechobee; vegetation; nitrogen |
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(2009) Bernhardt, C.E. and Willard, D.A. Response of the Everglades ridge and slough landscape to climate variability and 20th-century water management. Ecological Applications 19(7), 1723-1738. |
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ABSTRACT
The ridge and slough landscape of the Florida Everglades consists of a mosaic of linear sawgrass ridges separated by deeper-water sloughs with tree islands interspersed throughout the landscape. We used pollen assemblages from transects of sediment cores spanning sawgrass ridges, sloughs, and ridge-slough transition zones to determine the timing of ridge and slough formation and to evaluate the response of components of the ridge and slough landscape to climate variability and 20th-century water management. These pollen data indicate that sawgrass ridges and sloughs have been vegetationally distinct from one another since initiation of the Everglades wetland in mid-Holocene time. Although the position and community composition of sloughs have remained relatively stable throughout their history, modern sawgrass ridges formed on sites that originally were occupied by marshes. Ridge formation and maturation were initiated during intervals of drier climate (the Medieval Warm Period and the Little Ice Age) when the mean position of the Intertropical Convergence Zone shifted southward. During these drier intervals, marsh taxa were more common in sloughs, but they quickly receded when precipitation increased. Comparison with regional climate records suggests that slough vegetation is strongly influenced by North Atlantic Oscillation variability, even under 20th-century water management practices.
KEYWORDS:climate variability; Everglades; Florida, USA; late Holocene;
paleoecology; pollen; wetlands
intertropical convergence zone; medieval warm period; florida
everglades; drought frequency; plant community; south florida;
united-states; ice-age; rainfall; precipitation |
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(2009) Bohlen, P.J., Lynch, S., Shabman, L., Clark, M., Shukla, S. and Swain, H. Paying for environmental services from agricultural lands: an example from the northern Everglades. Frontiers in Ecology and the Environment 7(1), 46-55. |
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ABSTRACT
There is growing interest in implementing market-like programs that would pay farmers and ranchers for producing environmental services (beyond those that generate food and fiber) from working agricultural lands. However, few examples exist of programs that pay directly for quantified services. Since 2005, a coalition of non-governmental environmental organizations, state and federal agencies, ranchers, and researchers has been developing a Pay-for-Environmental Services (PES) program that would compensate cattle ranchers in Florida's northern Everglades region for providing water storage and nutrient retention on private lands. We use our experience with this program to identify key challenges to PES program design, including identifying a buyer and defining the environmental services; agreeing upon credible, yet practical, approaches to quantifying the services provided; reducing programmatic costs in light of existing policies and complex regulatory issues; and maintaining an adaptive approach to program design and implementation, while satisfying the concerns of multiple stakeholders.
KEYWORDS:ecosystem services; lake okeechobee; systems; management; payments;
ecology; florida; biodiversity; phosphorus; governance |
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(2009) Boulton, R.L., Lockwood, J.L., Davis, M.J., Pedziwilk, A., Boadway, K.A., Boadway, J.J.T., Okines, D. and Pimm, S.L. Endangered Cape Sable Seaside Sparrow Survival. Journal of Wildlife Management 73(4), 530-537.. |
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ABSTRACT
We investigated survival for male, female, and first-year Cape Sable seaside sparrows (Ammodramus maritimus mirabilis, hereafter sparrows), a federally endangered bird restricted to the Florida Everglades, USA. Accurate estimates of survival are critical to improve management decisions and population estimates for this and other threatened species. We used Program MARK to evaluate effects of age, sex, population membership, temporal variation, and ground-water levels on annual survival from mark-recapture data collected across 3 sparrow populations from 1997 to 2007. We found little evidence that annual survival rates differed between the populations or across ground-water levels, but we found high variability between years for both adult and juvenile survival. Our results revealed female sparrows experienced 14-19% lower survival than males. Sparrows experienced much lower survival during their first year of life and were short-lived (2-3 yr). Our results highlight sparrows' susceptibility to population declines and suggest that management actions aimed at increasing survival may be effective for this species' management.
KEYWORDS:age-specific; Ammodramus maritimus mirabilis; Florida Everglades;
mark-recapture; seaside sparrow; sex differences; survival; water levels
everglades restoration; bird populations; management; florida; models;
consequences; extinction; incubation; ecosystem; rates |
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(2009) Boyd, E.S., King, S., Tomberlin, J.K., Nordstrom, D.K., Krabbenhoft, D.P., Barkay, T. and Geesey, G.G. Methylmercury enters an aquatic food web through acidophilic microbial mats in Yellowstone National Park, Wyoming. Environmental Microbiology 11(4), 950-959. |
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ABSTRACT
Microbial mats are a visible and abundant life form inhabiting the extreme environments in Yellowstone National Park (YNP), WY, USA. Little is known of their role in food webs that exist in the Park's geothermal habitats. Eukaryotic green algae associated with a phototrophic green/purple Zygogonium microbial mat community that inhabits low-temperature regions of acidic (pH similar to 3.0) thermal springs were found to serve as a food source for stratiomyid (Diptera: Stratiomyidae) larvae. Mercury in spring source water was taken up and concentrated by the mat biomass. Monomethylmercury compounds (MeHg+), while undetectable or near the detection limit (0.025 ng l(-1)) in the source water of the springs, was present at concentrations of 4-7 ng g(-1) dry weight of mat biomass. Detection of MeHg+ in tracheal tissue of larvae grazing the mat suggests that MeHg+ enters this geothermal food web through the phototrophic microbial mat community. The concentration of MeHg+ was two to five times higher in larval tissue than mat biomass indicating MeHg+ biomagnification occurred between primary producer and primary consumer trophic levels. The Zygogonium mat community and stratiomyid larvae may also play a role in the transfer of MeHg+ to species in the food web whose range extends beyond a particular geothermal feature of YNP.
KEYWORDS:methyl mercury; experimental reservoir; florida everglades; trophic
transfer; hot-springs; bioaccumulation; accumulation; river; water;
communities |
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(2009) Boyer, J.N., Kelble, C.R., Ortner, P.B. and Rudnick, D.T. Phytoplankton bloom status: Chlorophyll a biomass as an indicator of water quality condition in the southern estuaries of Florida, USA. Ecological Indicators 9(S56-S67). |
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ABSTRACT
Altered freshwater inflows have affected circulation, salinity, and water quality patterns of Florida Bay, in turn altering the structure and function of this estuary. Changes in water quality and salinity and associated loss of dense turtle grass and other submerged aquatic vegetation (SAV) in Florida Bay have created a condition in the bay where sediments and nutrients have been regularly disturbed, frequently causing large and dense phytoplankton blooms. These algal and cyanobacterial blooms in turn often cause further loss of more recently established SAV, exacerbating the conditions causing the blooms. Chlorophyll a (CHLA) was selected as an indicator of water quality because it is an indicator of phytoplankton biomass, with concentrations reflecting the integrated effect of many of the water quality factors that may be altered by restoration activities. Overall, we assessed the CHLA indicator as being (1) relevant and reflecting the state of the Florida Bay ecosystem, (2) sensitive to ecosystem drivers (stressors, especially nutrient loading), (3) feasible to monitor, and (4) scientifically defensible. Distinct zones within the bay were defined according to statistical and consensual information. Threshold levels of CHLA for each zone were defined using historical data and scientific consensus. A presentation template of condition of the bay using these thresholds is shown as an example of an outreach product.
KEYWORDS:Water quality; Florida Bay; Phytoplankton; Algal bloom; Chlorophyll a
long-term trends; inner-shelf; bay; nutrient; variability;
distributions; everglades; phosphorus; limitation; management |
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(2009) Browder, J.A. and Robblee, M.B. Pink shrimp as an indicator for restoration of everglades ecosystems. Ecological Indicators 9(S17-S28). |
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ABSTRACT
The pink shrimp, Farfantepenaeus duorarum, familiar to most Floridians as either food or bait shrimp, is ubiquitous in South Florida coastal and offshore waters and is proposed as an indicator for assessing restoration of South Florida's southern estuaries: Florida Bay, Biscayne Bay, and the mangrove estuaries of the lower southwest coast. Relationships between pink shrimp and salinity have been determined in both field and laboratory studies. Salinity is directly relevant to restoration because the salinity regimes of South Florida estuaries, critical nursery habitat for the pink shrimp, will be altered by changes in the quantity, timing, and distribution of freshwater in flow planned as part of the Comprehensive Everglades Restoration Project (CERP). Here we suggest performance measures based on pink shrimp density (number per square meter) in the estuaries and propose a restoration assessment and scoring scheme using these performance measures that can readily be communicated to managers, policy makers, and the interested public. The pink shrimp is an appropriate restoration indicator because of its ecological as well as its economic importance and also because scientific interest in pink shrimp in South Florida has produced a wealth of information about the species and relatively long time series of data on both juveniles in estuarine nursery habitats and adults on the fishing grounds. We suggest research needs for improving the pink shrimp performance measure.
KEYWORDS:Penaeid; Farfantepenaeus duorarum; Stoplight; Florida Bay; Biscayne
Bay; Whitewater Bay; Freshwater inflow; Estuaries
cross-shelf transport; western florida bay; penaeus-duorarum;
farfantepenaeus-duorarum; tortugas grounds; stable-isotope; mud banks;
abundance; communities; salinity |
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(2009) Cerna, B., Rejmankova, E., Snyder, J.M. and Santruckova, H. Heterotrophic nitrogen fixation in oligotrophic tropical marshes: changes after phosphorus addition. Hydrobiologia 627(1), 55-65. |
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ABSTRACT
In order to determine the impact of nutrient enrichment on phosphorus (P) limited wetlands, we established experimental P additions in marshes throughout northern Belize. P significantly increased macrophyte primary production, which led to the rapid elimination of cyanobacterial mats. The replacement of cyanobacterial mats by macrophytes constrained autotrophic nitrogen (N) fixation, increased the quantity, and changed the quality of organic matter input to the sediments. We predicted that the activity of sediment heterotrophic N fixers will be impacted by these alterations in carbon input. We used the acetylene reduction technique to measure potential (glucose amended) nitrogenase activity (NA) in sediments from controls and treatment plots that have been P enriched for four years and dominated either by Eleocharis cellulosa, or Typha domingensis for two years. NA in P-enriched plots was 2-3 orders of magnitude higher than NA in controls. NA was positively correlated with the soil reactive P, both total organic and microbial carbon, live root biomass, and total phospholipid fatty acids (PLFA) as an indicator of active microbial biomass. It was negatively correlated with the concentration of ammonium-N. Path analysis revealed that the indirect effect of P on NA through the root biomass was more important than the direct effect of P. NA of the upper sediment layer was consistently higher in Eleocharis than in Typha dominated plots, despite the higher litter input by Typha. We feel that the higher levels of lignin and phenolics occurring in Typha litter, relative to Eleocharis, constrained NA in Typha plots.
KEYWORDS:Heterotrophic nitrogen fixation; Typha; Eleocharis; Cyanobacteria;
Phosphorus; Salinity
salt-marsh; fresh-water; acetylene-reduction; spartina-alterniflora;
northern belize; cyanobacterial mats; florida everglades; microbial
biomass; marine ecosystems; sulfate reduction |
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(2009) Chang, C.C.Y., McCormick, P.V., Newman, S. and Elliott, E.M. Isotopic indicators of environmental change in a subtropical wetland. Ecological Indicators 9(5), 825-836. |
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ABSTRACT
The delta N-15 and delta C-13 signatures of major organic matter (OM) pools were measured across chemical and hydrologic gradients in a large (58,800 ha) subtropical wetland to evaluate whether stable isotopes were useful indicators of environmental change. Once a rainfall-driven wetland, the Loxahatchee National Wildlife Refuge in the Florida Everglades now receives agricultural and urban drainage that has increased phosphorus (P) and mineral loads around the wetland perimeter. Additionally, water impoundment at the southern end has produced a latitudinal hydrologic gradient, with extended hydroperiods in the south and overdrained conditions in the north. Detritus (-4.8 parts per thousand to 8.6 parts per thousand), floc (-1.4 parts per thousand to 3.6 parts per thousand), and metaphyton (-6.6 parts per thousand to +7.4 parts per thousand) delta N-15 declined southward with changes in hydrology as indicated by water depth. This pattern was attributed to higher mineralization rates under shorter hydroperiods. These signatures were also strongly correlated with increased nutrient and mineral loading. Rooted macrophyte delta N-15, by contrast, appeared more responsive to soil nutrient pools. Cattail (-8.9 parts per thousand to +7.7 parts per thousand) was restricted to the wetland perimeter and had the widest delta N-15 range, which was positively correlated with soil P. Sawgrass (-5.3 parts per thousand to +7.7 parts per thousand) occurred across most of the wetland, but its ON was not strongly correlated to any gradient. Patterns for delta C-13 were more strongly related to chemical gradients caused by canal intrusion than to latitude or hydrology. Again, metaphyton and detrital signatures were more sensitive to water chemistry changes than macrophytes. This pattern is consistent with their locations at the soil-water (detritus-floc), and air-water (metaphyton) interface. Metaphyton delta C-13 (-36.1 parts per thousand to -21.5 parts per thousand) which had the broadest range, was affected by DIC source and pool size. In contrast, cattail delta C-13 (-28.7 parts per thousand to -26.4 parts per thousand) was more closely related to soil P and sawgrass delta C-13 (-30.1 parts per thousand to -24.5 parts per thousand) was not related to any environmental gradient except latitude. There was no correlation between the two isotopes for any OM pool except cattail. These results indicate that isotopic signatures of microbial (metaphyton and detrital) pools are more responsive to changes in wetland hydrology and water chemistry while those of rooted macrophytes respond only to the extent that soil chemistry is altered. Rooted macrophytes also differ in the sensitivity of their isotopic signatures to environmental change. The selection of OM pools for isotopic analysis will, therefore, affect the sensitivity of the analysis and the resulting patterns. Furthermore, delta N-15 may be more robust and interpretable than delta C-13 as an indicator of ecosystem change in wetlands exposed to multiple or complex anthropogenic gradients.
KEYWORDS:Hydrology; Macrophytes; Metaphyton; Soil; Stable isotopes; Water
quality; Wetlands
organic nitrogen mineralization; northern everglades; stable isotopes;
delta n-15; nitrate; fractionation; carbon; soils; water; Florida |
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(2009) Chartrand, K.M. and Durako, M.J. Distribution and Photobiology of Siderastrea radians and Thalassia Testudinum in Florida Bay, Florida, USA.
Bulletin of Marine Science 84(2), 153-166. |
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ABSTRACT
The distribution of Siderastrea radians (Pallas) Blainville and photophysiology of its symbiont in Florida Bay, USA, were examined during annual macrophyte surveys in spring 2006 and 2007. Siderastrea radians was present in five of the 11 sampled basins in areas with little sediment and low abundance of the seagrass Thalassia testudinum Banks ex Konig. The five basins are located along a northeast-to-southwest transect that also represents a salinity gradient from inshore, predominantly estuarine conditions adjacent to the Everglades, to offshore near-marine salinities adjacent to the Gulf of Mexico. Colony abundance was highest in the basins at the extremes of this physical range, presumably due to higher potential for larval recruitment from external reef source populations. Effective quantum yields, measured in situ by PAM fluorometry, were significantly correlated between S. radians and the dominant seagrass T. testudinum among all five basins where the two species co-occurred, albeit with a 40% reduction in mean yields of S. radians. These findings indicate S. radians may function as an alternative eco-indicator species for regions in Florida Bay where T. testudinum is absent.
KEYWORDS:photosynthetic characteristics; scleractinian corals; seagrass
habitats; photosystem-ii; light curves; efficiency; fluorescence;
abundance; photoprotection; communities |
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(2009) Cohen, M.J., Lamsal, S., Osborne, T.Z., Bonzongo, J.C.J., Newman, S. and Reddy, K.R. Soil Total Mercury Concentrations across the Greater Everglades. Soil Science Society of America Journal 73(2), 675-685. |
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ABSTRACT
Elevated Hg concentrations in the Everglades pose ecological and human health risks. We mapped soil total Fig concentrations per mass (THgM) and area THgA) across the Everglades, and investigated relationships with soil properties (total P [TP] and organic matter content), community type, and hydrologic compartmentalization. Samples (n = 600) from surface soils (0-10 cm) were selected from a Population of 1405 sites spanning the Everglades. Overall, 168 sites had THgM levels >0.2 mg kg(-1); interpolation suggests that 23% of the Greater Everglades exceeds this threshold. Hot spots (>0.4 mg kg(-1)) were observed in eastern Water Conservation Area (WCA) 1 and west-central WCA3A; parts of WCA2A, WCA3AN, and WCA3B were locally high. Despite significant global differences in THgM among plant Communities, differences evaluated using paired proximate sites were not significant, suggesting that large spatial scale depositional gradients govern ecosystem storage. Median THgA was 1.89 mg m(-2) (range 0.07-12.05 mg m(-2)), representing approximately 100 yr of atmospheric deposition at contemporary rates (similar to 19 mu g m(-2) yr(-1)). Correlation between TP and THgM was positive in unimpacted areas (TP < 500 mg kg(-1), r = 0.69), but negative in impacted areas (TP > 500 mg kg(-1), r = -0.47), probably due to accelerated peat accretion rates in P-enriched areas. Moreover, while reverse correlation with distance from a canal for THgM (0.70) and TP (-0.77) supports Hg enrichment via atmospheric deposition, THgM hotspots in WCA3AS, WCA1, and the Holeyland and Rotenberger tracts are suggestive of local enrichment mechanisms. Finally, despite dramatic regional emissions declines, the estimated mass of Hg in surface soils across the Everglades has increased similar to 20% (11,000 vs. 13,100 kg) since 1996; while the statistical significance of this change is unknown, it provides a useful benchmark for future surveys.
KEYWORDS:Florida Everglades; spatial-distribution; methyl mercury; water; peat;
methylmercury; accumulation; ecosystems; phosphorus; sediment |
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(2009) Corstanje, R., Portier, K.M. and Reddy, K.R. Discriminant analysis of biogeochemical indicators of nutrient enrichment in a Florida wetland.
European Journal of Soil Science 60(6), 974-981. |
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ABSTRACT
Eutrophication of wetlands can lead to extensive changes in the ecosystem structures. The water-borne nutrient inputs change the soil biogeochemistry prior to structural changes in the ecosystem. The objective of this study was to determine the biogeochemical variables that are strongly associated with eutrophication. We postulated that in wetlands the soil chemical properties function as driving factors (primary indicators) to which the indicators of the soil biological processes respond (secondary indicators). The alternative hypothesis is that the soil biology shows a more rapid response to an increase in nutrient availability from the water column, with the soil chemical properties responding more slowly. This study employed an extensive database from three sites covering a nutrient enrichment gradient in the Everglades, Florida (enriched, intermediate and unenriched). This database contained 28 biogeochemical variables, which we divided into two sets: a set of chemical descriptors and a set of microbiological descriptors. We applied a combination of stepwise discrimination and canonical discrimination ("stepwise canonical discrimination") to determine differences between the sites. For the group of chemical descriptors, the variables selected were total nitrogen (N), total carbon (C), organic C, labile organic phosphorus (P), fulvic-, humic-, labile inorganic- and residual P, ammonia and aluminium. We then applied the discriminant analysis using the microbiological descriptors. The variables selected were mineralizable P and N, microbial P and phosphatase activity. Discrimination using chemical variables was more successful than that based on the microbiological variables. Subsequent bootstrap cross-validation indicated that the microbiological variables seemed to have a more integrative function with associated stability and robustness. We suggest that for this system the canonical variates themselves may be viewed as indicator variables of enrichment, and that the constituent variables may be important as indicators in other P-limited marsh systems at risk of eutrophication.
KEYWORDS:northern everglades marsh; spatial-distribution; soil quality;
phosphorus |
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(2009) Covelli, S., Acquavita, A., Piani, R., Predonzani, S. and De Vittor, C. Recent contamination of mercury in an estuarine environment (Marano lagoon, Northern Adriatic, Italy). Estuarine Coastal and Shelf Science 82(2), 273-284. |
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ABSTRACT
The Marano Lagoon, in the northern Adriatic Sea (Italy), has been affected by mercury (Hg) contamination from industrial and mining activities. It has been estimated that 186,000 kg of Hg were deliberately discharged into the main drainage system (Aussa-Corno River) by a chlor-alkali plant (CAP) from 1940s to 1984. The lagoon has also experienced a secondary long-term Hg input, originated from mining activity in Idrija (Slovenia), due to the supply of fluvial suspended particles carried by the Isonzo River in the Gulf of Trieste. Since local fishing activities are extensively conducted, there is great concern on the risk posed by potentially harmful effects of Hg to the trophic chain. Present inputs of this metal, both in dissolved (52.4-4.1 ng L-1) and particulate (130.8-3.4 ng L-1) phases, were preliminary investigated in the water column. Although direct discharge of Hg from the CAP no longer exists, the metal is still released from the source area into freshwaters, and its distribution and abundance is controlled by the salt-wedge circulation system, which is tide-influenced. Remobilization from bottom sediments can also be a secondary source of Hg into the aquatic environment. A speciation technique, used to investigate the main binding sites and phase associations of Hg in sediments (5.69-0.82 mu g g(-1)), evidenced the presence of mobile (1.8-11%) and potentially available species for methylation processes. The results are particularly important if related to resuspension effects caused by natural events and anthropogenic activities. Preliminary considerations on Hg behaviour in this estuarine environment are reported.
KEYWORDS:mercury; chlor-alkali; estuary; biogeochemical cycling; total suspended
matter; sediments
dissolved organic-matter; marine-sediments; aquatic environment;
florida everglades; chloralkali plants; elemental mercury; soils;
river; sea; speciation |
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(2009) Cunningham, M.W., Shindle, D.B., Allison, A.B., Terrell, S.P., Mead, D.G. and Owen, M. Canine Distemper Epizootic in Everglades Mink.
Journal of Wildlife Diseases 45(4), 1150-1157. |
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ABSTRACT
Four free-ranging mink, Neovison vison, collected between June and September 2004 in the Fakahatchee Strand Preserve State Park (FSPSP, Florida, USA), were examined for canine distemper virus (CDV) infection. Microscopic lesions and viral inclusions consistent with CDV infection were observed in three mink. Virus isolation and reverse transcription-polymerase chain reaction performed on all mink were positive for CDV. Anecdotal records of mink observations in FSPSP suggest a postepizootic decline in the mink population followed by an apparent recovery. We recommend further research to assess the status of the Everglades mink and the impact of CDV on this and other American mink populations in Florida.
KEYWORDS:Canine distemper virus; Everglades mink; morbillivirus; Mustela;
Neovison vison evergladensis; southern Florida
mustela-lutreola; european mink; carnivores; toxoplasmosis; virus; dogs |
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(2009) da Rocha, F.C., Casatti, L., Carvalho, F.R. and da Silva, A.M. Fish assemblages in stream stretches occupied by cattail (Typhaceae, Angiospermae) stands in Southeast Brazil. Neotropical Ichthyology 7(2), 241-250. |
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ABSTRACT
Macrophytes are a major component of lentic and lotic aquatic ecosystems. As consequences of environmental degradation, species of cattail (genus Typha) may become dominant along streams. The purpose of this study was to investigate the structure and feeding of fish assemblages in stream stretches under influence of Typha sp., also addressing the influences of temporal variation on composition, abundance, biomass, diversity, species richness, and feeding of fish. Six streams (labelled S1-S6) in the upper rio Turvo basin, southeast Brazil, with dense stands of Typha sp. in the instream and riparian habitat, were studied in six campaigns during three central months in both of the dry and wet periods, by using a standardized collection effort. Thirty-seven fish species were registered, totaling 4,228 individuals and 3.9 kg of biomass. Abundance, biomass, diversity, and species richness was higher in the wet period, but only the temporal variation in the species richness revealed to be statistically significant. Cluster analyses with composition and abundance showed little temporal similarity, but indicated two groups of streams (S1-S2-S5 and S3-S4-S6), that were corroborated along the axis 1 of the ordination analysis. Resident species was represented by six species, most of them considered tolerant and generalists. Chironomidae aquatic larvae and detritus were the most important items in the fish diet. These results suggest that the fish populations are opportunistic in exploring stream stretches occupied by cattail.
KEYWORDS:Disturbance; Chironomidae larvae; Detritus; Macrophytes; Upper rio
Parana
nutrient enrichment; sao-paulo; water; habitat; invertebrates;
availability; macrophytes; everglades; abundance; basin |
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(2009) Daroub, S.H., Lang, T.A., Diaz, O.A. and Grunwald, S. Long-term Water Quality Trends after Implementing Best Management Practices in South Florida. Journal of Environmental Quality 38(4), 1683-1693. |
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ABSTRACT
A mandatory best management practices (BMP) program was implemented in the Everglades Agricultural Area (EAA) farms basin-wide in 1995 as required by the Everglades Forever Act to reduce P loads in drainage water reaching the Everglades ecosystem. All firms in the EAA basin implement similar BMPs, and basin wide P load reductions have exceeded the 25% reduction required by law; however, differences remain in water quality between subbasins. Our objective was to determine long-term trends in P loads in discharge water in the EAA after implementing BMPs for 7 to 10 yr and to explore reasons for differences in the performance of the subbasins. Two monitoring datasets were used, one from 10 research firms and the second from the EAA basin inflow and outflow locations. Mann-Kendall trend analysis was used to determine the degree of change in water quality trends. A decreasing trend in P loads was observed in general on sugarcane (Saccharum officinarum L.) firms, while mixed crop firms showed either decreasing or insignificant trends. The insignificant trends are probably related to management practices of mixed crop systems. Decreasing trends in P loads were observed in the outflow of the EAA basin, S5A, and S8 subbasins from 1992 to 2002. Inflow water from Lake Okeechobee had increasing P concentration front 1992 to 2006 with the highest trend in the cast side of the lake. This analysis indicated there may be other factors impacting the success of BMPs in individual farms including cropping rotations and flooding of organic soils. Elevated P concentrations in Lake Okeechobee water used for irrigation may pose a future risk to degrade water quality on farms in the EAA, especially in the S5A subbasin.
KEYWORDS:everglades agricultural area; soil-phosphorus; subtropical lake;
organic soils; release; runoff; strategies; transport; pastures; systems |
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(2009) DeLaune, R.D., Gambrell, R.P., Devai, I., Jugsujinda, A. and Kongchum, M. Total Hg and methyl Hg distribution in sediments of selected Louisiana water bodies. Journal of Environmental Science and Health Part a-Toxic/Hazardous Substances & Environmental Engineering 44(6), 557-567. |
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ABSTRACT
Sediment samples (543) collected from selected Louisiana streams and lakes were analyzed for total Hg and methyl Hg content. The average total Hg content among 543 samples was 92.3 95.1 g kg-1. The average methyl Hg content in the samples was 0.68 0.80 g kg-1. Methyl Hg accounted for an average of 0.73% of the total Hg in sediment. Linear regression analysis of total Hg versus methyl Hg content of the sediment showed methyl Hg content was significantly correlated to total Hg content of sediment (P 0.01, n = 537) and sediment organic matter content. (P 0.01, n = 536) Methyl Hg was also positively correlated to clay (P 0.01, n = 537) and inversely correlated to sand content of sediment (P 0.01, n = 537). Total Hg and methyl Hg content in these sediments was within the normal range reported elsewhere indicating no significant industrial or municipal Hg contamination. A comparison of selected water bodies with fishing advisories showed no relationship to total Hg and methyl Hg in sediment.
KEYWORDS:Hg accumulation; sediment Hg; Louisiana; water bodies fish contamination
atomic fluorescence spectrometry; capillary gas-chromatography; florida
everglades; mercury; fish; samples; soils |
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(2009) Doren, B. and Doren, R.F. Indicators for Everglades Restoration. Ecological Indicators 9(S1-S1). |
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ABSTRACT (none)
KEYWORDS:Indicators. Everglades restoration. |
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(2009a) Doren, R.F., Richards, J.H. and Volin, J.C. A conceptual ecological model to facilitate understanding the role of invasive species in large-scale ecosystem restoration. Ecological Indicators 9(S150-S160). |
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ABSTRACT
We developed a conceptual ecological model (CEM) for invasive species to help understand the role invasive exotics have in ecosystem ecology and their impacts on restoration activities. Our model, which can be applied to any invasive species, grew from the eco-regional conceptual models developed for Everglades restoration. These models identify ecological drivers, stressors, effects and attributes; we integrated the unique aspects of exotic species invasions and effects into this conceptual hierarchy. We used the model to help identify important aspects of invasion in the development of an invasive exotic plant ecological indicator, which is described a companion paper in this special issue journal. A key aspect of the CEM is that it is a general ecological model that can be tailored to specific cases and species, as the details of any invasion are unique to that invasive species. Our model encompasses the temporal and spatial changes that characterize invasion, identifying the general conditions that allow a species to become invasive in a de novo environment; it then enumerates the possible effects exotic species may have collectively and individually at varying scales and for different ecosystem properties, once a species becomes invasive. The model provides suites of characteristics and processes, as well as hypothesized causal relationships to consider when thinking about the effects or potential effects of an invasive exotic and how restoration efforts will affect these characteristics and processes. In order to illustrate how to use the model as a blueprint for applying a similar approach to other invasive species and ecosystems, we give two examples of using this conceptual model to evaluate the status of two south Florida invasive exotic plant species (melaleuca and Old World climbing fern) and consider potential impacts of these invasive species on restoration.
KEYWORDS:Conceptual ecological model; CEM; Ecological restoration; Restoration
planning; Everglades restoration; Invasive species; Melaleuca
quinquenervia; Lygodium microphyllum
tree melaleuca-quinquenervia; biological-control agent; fern
lygodium-microphyllum; south florida; oxyops-vitiosa; introduced
insects; cav. blake; everglades; herbivory; growth |
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(2009b) Doren, R.F., Trexler, J.C., Gottlieb, A.D. and Harwell, M.C. Ecological indicators for system-wide assessment of the greater everglades ecosystem restoration program. Ecological Indicators 9(S2-S16). |
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ABSTRACT
Developing scientifically credible tools for measuring the success of ecological restoration projects is a difficult and a non-trivial task. Yet, reliable measures of the general health and ecological integrity of ecosystems are critical for assessing the success of restoration programs. The South Florida Ecosystem Restoration Task Force (Task Force), which helps coordinate a multi-billion dollar multi-organizational effort between federal, state, local and tribal governments to restore the Florida Everglades, is using a small set of system-wide ecological indicators to assess the restoration efforts. A team of scientists and managers identified eleven ecological indicators from a field of several hundred through a selection process using 12 criteria to determine their applicability as part of a system-wide suite. The 12 criteria are: (1) is the indicator relevant to the ecosystem? (2) Does it respond to variability at a scale that makes it applicable to the entire system? (3) is the indicator feasible to implement and is it measureable? (4) Is the indicator sensitive to system drivers and is it predictable? (5) Is the indicator interpretable in a common language? (6) Are there situations where an optimistic trend with regard to an indicator might suggest a pessimistic restoration trend? (7) Are there situations where a pessimistic trend with regard to an indicator may be unrelated to restoration activities? (8) Is the indicator scientifically defensible? (9) Can clear, measureable targets be established for the indicator to allow for assessments of success? (10) Does the indicator have specificity to be able to result in corrective action? (11) What level of ecosystem process or structure does the indicator address? (12) Does the indicator provide early warning signs of ecological change? In addition, a two page stoplight report card was developed to assist in communicating the complex science inherent in ecological indicators in a common language for resource managers, policy makers and the public. The report card employs a universally understood stoplight symbol that uses green to indicate that targets are being met, yellow to indicate that targets have not been met and corrective action maybe needed and red to represent that targets are far from being met and corrective action is required. This paper presents the scientific process and the results of the development and selection of the criteria, the indicators and the stoplight report card format and content. The detailed process and results for the individual indicators are presented in companion papers in this special issue of Ecological indicators.
KEYWORDS:Ecosystem restoration; Ecosystem integrity; Ecological performance
measures; Ecosystem report cards; Ecological indicator development;
Everglades; South Florida ecosystem
south florida; framework; management; integrity; science; recovery;
criteria |
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(2009c) Doren, R.F., Volin, J.C. and Richards, J.H. Invasive exotic plant indicators for ecosystem restoration: An example from the Everglades restoration program. Ecological Indicators 9(S29-S36). |
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ABSTRACT
We have developed a comprehensive ecological indicator for invasive exotic plants, a human-influenced component of the Everglades that could threaten the success of the restoration initiative. Following development of a conceptual ecological model for invasive exotic species, presented as a companion paper in this special issue, we developed criteria to evaluate existing invasive exotic monitoring programs for use in developing invasive exotic performance measures. We then used data from the selected monitoring programs to define specific performance measures, using species presence and abundance as the basis of the indicator for invasive exotic plants. We then developed a series of questions used to evaluate region and/or individual species status with respect to invasion. Finally, we used an expert panel who had answered the questions for invasive exotic plants in the Everglades Lake Okeechobee model to develop a stoplight restoration report card to communicate invasive exotic plant status. The report card system provides a way to effectively evaluate and present indicator data to managers, policy makers, and the public using a uniform format among indicators. Collectively, the model, monitoring assessment, performance measures, and report card enable us to evaluate how invasive plants are impacting the restoration program and how effectively that impact is being managed. Applied through time, our approach also allows us to follow the progress of management actions to control the spread and reduce the impacts of invasive species and can be easily applied and adapted to other large-scale ecosystem projects.
KEYWORDS:Invasive plants; Exotic plants; Everglades restoration; Monitoring;
Performance measures
management |
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(2009) Doyle, T.W., Krauss, K.W. and Wells, C.J. Landscape Analysis and Pattern of Hurricane Impact and Circulation on Mangrove Forests of the Everglades. Wetlands 29(1), 44-53. |
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ABSTRACT
The Everglades ecosystem contains the largest contiguous tract of mangrove forest Outside the tropics that were also coincidentally intersected by a major Category 5 hurricane. Airborne videography was flown to Capture the landscape patient and process of forest damage in relation to storm trajectory and circulation. TWO aerial video transects, representing different topographic positions, were used to quantify forest damage from video frame analysis in relation to prevailing wind force, treefall direction, and forest height. A hurricane simulation model wits applied to reconstruct wind fields corresponding to the ground location of each video frame and to correlate observed treefall and destruction patterns with wind speed and direction. Mangrove forests within the storm's eyepath and ill the right-side (forewind) quadrants suffered whole or partial blowdowns, while left-side (backwind) sites South of the eyewall zone incurred moderate canopy reduction and defoliation. Sites along file coastal transect sustained substantially more storm damage than sites along the inland transect which may be attributed to differences in stand exposure and/or Mature. Observed treefall directions were shown to be non-random and associated with hurricane trajectory and simulated forewind azimuths. Wide-area sampling using airborne videography provided an efficient adjunct to limited ground observations and improved our spatial understanding of how hurricanes imprint landscape-scale patterns of disturbance.
KEYWORDS:aerial videography; damage assessment; Everglades National Park;
Hurricane Andrew; remote sensing; southwest Florida; spatial analysis;
Ten Thousand Islands National Wildlife Refuge
airborne video imagery; south florida; damage; andrew; region; Texas; |
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(2009) Dray, F.A., Hale, R.E., Madeira, P.T., Bennett, B.C. and Center, T.D. Concordance between life history traits, invasion history, and allozyme diversity of the Everglades invader Melaleuca quinquenervia. Aquatic Botany 90(4), 296-302. |
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ABSTRACT
During the century following its initial introduction in 1886, the Australian tree Melaleuca quinquenervia (Myrtaceae) dispersed from a few introduction points to occupy over 200,000 ha, primarily in historic Everglades wetlands of southern Florida. Cellulose acetate gel electrophoresis (CAGE) was used to investigate the allozyme diversity and population genetic structure of 208 individuals in a dozen populations resulting from this invasion. The analyses showed that these populations have a high (82%) rate of polymorphic loci and an average of 2 alleles/locus. There was substantial heterozygosity (mean H-e = 0.356), which concords well with recent studies reporting a greater number of introduction events and sources than generally recognized. The introduction history and distributional patterns within Florida have led to geographic structuring (G(ST) = 0.419) in which the Gulf Coast metapopulation has a greater effective number of alleles and greater heterozygosity than the Atlantic Coast metapopulation. The gene diversity in M. quinquenervia was comparable to other tropical woody species. Its strong population divergence was reminiscent of pioneer species and consistent with its status as a plant invader in Florida.
KEYWORDS:Allozyme; Biological control; Cellulose acetate gel electrophoresis;
Genetic diversity; Invasive species; Life history trait; Melaleuca
quinquenervia; Myrtaceae
plant-populations; genetic diversity; florida; distance; trees |
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(2009) Duncan, B.W., Shao, G.F. and Adrian, F.W. Delineating a managed fire regime and exploring its relationship to the natural fire regime in East Central Florida, USA: A remote sensing and GIS approach. Forest Ecology and Management 258(2), 132-145. |
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ABSTRACT
A managed fire regime on John F. Kennedy Space Center, Florida and surrounding federal properties was mapped using time series satellite imagery and GIS techniques. Our goals were to: (1) determine if an image processing technique designed for individual fire scar mapping could be applied to an image time series for mapping a managed fire regime in a rapid re-growth pyrogenic system; (2) develop a method for labeling mapped fire scar confidence knowing a formal accuracy analysis was not possible; and (3) compare results of the managed fire regime with regional information on natural fire regimes to look for similarities/differences that might help optimize management for persistence of native fire-dependent species. We found that the area burned by managed fire peaked when the drought index was low and was reduced when the drought index was high. This contrasts with the expectations regarding the natural fire regime of this region. With altered natural fire regimes and fire-dependent species declining in many pyrogenic ecosystems, it is important to manage fire for the survival of fire-adapted native species. The remote sensing and GIS techniques presented are effective for delineating and monitoring managed fire regimes in shrub systems that grow rapidly and may be appropriate for other fire-dependent systems world wide.
KEYWORDS:Fire regime; Florida; Southeastern United States; Remote sensing; GIS
everglades-national-park; longleaf pine savannas; burn severity;
landsat-tm; population; patterns; season; scrub; restoration; ecosystems |
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(2009) Escutia-Lara, Y., Gomez-Romero, M. and Lindig-Cisneros, R. Nitrogen and phosphorus effect on Typha domingensis Presl. rhizome growth in a matrix of Schoenoplectus americanus (Pers.) Volkart ex Schinz and Keller. Aquatic Botany 90(1), 74-77. |
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ABSTRACT
In an outdoor mesocosm experiment of 80 weeks, the effect of nitrogen and phosphorus addition was tested on growth of Typha domingensis Presl. rhizomes in a matrix of Schoenoplectus americanus (Pets.) Volkart ex Schinz and Keller, under loading rates of 0.23 gm(-2) d(-1) of nitrogen, 0.17 gm(-2) d(-1) of P, both nutrient together and control conditions, to assess the potential expansion of T. domingensis in response to nutrient inputs. T. domingensis responded to nitrogen addition but not to phosphorus addition. When nitrogen was added, the number of rhizomes and their weight increased. Mesocosms with nitrogen had an average of 8 rhizomes, control mesocosms 5, the differences being significant (P < 0.05). Fresh rhizome biomass per mesocosm (0.58 m(2)) differed among treatments (P < 0.05): with nitrogen addition it was 110 (+/- 31) g, with phosphorus addition 71 (+/- 39) g, nitrogen and phosphorus 137 (+/- 57) g, control mesocosms 67 (+/- 30) g. The number and weight of rhizomes were highly correlated (Pearson's correlation = 0.84). Because T. domingensis responds to nitrogen additions by increasing the number and biomass of its rhizomes, it might be able to out-compete S. americanus when nitrogen concentrations increase.
KEYWORDS:Nutrient; Fire; Species diversity; Restoration; Management; Typha;
Schoenoplectus
everglades; nutrients; wetland; additions; communities; cladium; plants |
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(2009) Fiscus, D.A. Comparative network analysis toward characterization of systemic organization for human-environmental sustainability.
Ecological Modelling 220(22), 3123-3132. |
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ABSTRACT
A preliminary study in comparative ecological network analysis was conducted to identify key assumptions and methodological challenges, test initial hypotheses and explore systemic and network structural characteristics for environmentally sustainable ecosystems. A nitrogen network for the U.S. beef supply chain - a small sub-network of the industrial food system analyzed as a pilot study - was constructed and compared to four non-human carbon and nitrogen trophic networks for the Chesapeake Bay and the Florida Everglades. These non-human food webs served as sustainable reference systems. Contrary to the main original hypothesis, the "window of vitality" and the number of network roles did not clearly differentiate between a human sub-network and the more complete non-human networks. The effective trophic level of humans (a partial estimate of trophic level based on the single food source of beef) was much higher (8.1) than any non-human species (maximum of 4.88). Network connectance, entropy, total dependency coefficients, trophic efficiencies and the ascendency to capacity ratio also indicated differences that serve as hypotheses for future tests on more comprehensive human food webs. The study elucidated important issues related to (1) the steady state assumption, which is more problematic for industrial human systems, (2) the absence or dearth of data on contributions of dead humans and human wastes to feed other species in an integrated food web, (3) the ambiguity of defining some industrial compartments as living versus non-living, and (4) challenges with constructing compartments and trophic transfers in industrial versus non-human food webs. The two main novel results are (1) the progress made toward adapting ecological network analysis (ENA) methodology for analysis of human food networks in industrial cultures and (2) characterizing the critical aspects of comparative ENA for understanding potential causes of the problems, and providing avenues for solutions, for environmental sustainability. Based on this work, construction and comparative network analysis of a more comprehensive industrial human food network seems warranted and likely to provide valuable insights for modifying structures of industrial food networks to be more like natural networks and more sustainable.
KEYWORDS:Ecological network analysis; Sustainability; Human food web
cattle feedlot manure; beef-cattle; food-production; nutrient;
nitrogen; dynamics; community; ecosystem; balance; silage |
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(2009) Frederick, P., Gawlik, D.E., Ogden, J.C., Cook, M.I. and Lusk, M. The White Ibis and Wood Stork as indicators for restoration of the everglades ecosystem. Ecological Indicators 9(S83-S95). |
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ABSTRACT
Large numbers of colonially nesting herons, egrets, ibises, storks and spoonbills were one of the defining natural phenomena of the historical Everglades. Reproduction of these species has been tracked over at least a century, and some clear responses to dramatic anthropogenic hydrological alterations have been established. These include a marked decline in nesting populations of several species, and a movement of colonies away from the over-drained estuarine region. Ponding in a large portion of the freshwater marsh has favored species that hunt by sight in deep water (egrets, cf. 25-45 cm), while tactile feeders (ibises and storks) that depend on concentrated prey in. shallow water (5-25 cm) have become proportionately much less common. There has been a marked increase in the interval between exceptionally large breeding aggregations of White Ibises (Eudocimus albus). Loss of short hydroperiod wetlands on the margins of the Everglades have delayed nest initiations 1-2 months by Wood Storks (Mycteria americana) resulting in poor nesting success. These responses are consistent with mechanisms that involve foraging, and the availability and production of prey animals, and each of the relationships is highly dependent on hydrology. Here, we define a group of characteristics about wading bird dynamics (= indicators) that collectively track the specific ecological relationships that supported ibises and storks in the past. We suggest four metrics as indicators of restoration success: timing of nesting by storks, the ratio of nesting ibises + storks to Great Egrets, the proportion of all nests located in the estuarine/freshwater ecotone, and the interval between years with exceptionally large ibis nestings. Each of these metrics has historical (e.g., predrainage) data upon which to base expectations for restoration, and the metrics have little measurement error relative to the large annual variation in numbers of nests. In addition to the strong scientific basis for the use of these indicators, wading birds are also a powerful tool for public communication because they have strong aesthetic appeal, and their ecological relationships with water are intuitively understandable. In the interests of communicating with the public and decision-makers, we integrate these metrics into a single-page annual "traffic-light" report card for wading bird responses. Collectively, we believe these metrics offer an excellent chance of detecting restoration of the ecosystem functions that supported historical wading bird nesting patterns.
KEYWORDS:Ecological indicators; Eudocimus albus; Everglades; Mycteria americana;
Restoration
wading birds; florida everglades; population-dynamics; community
structure; united-states; wetland; prey; conservation; disturbance;
model |
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(2009) Fujisaki, I., Rice, K.G., Pearlstine, L.G. and Mazzotti, F.J. Relationship between body condition of American alligators and water depth in the Everglades, Florida. Hydrobiologia 635(1), 329-338. |
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ABSTRACT
Feeding opportunities of American alligators (Alligator mississippiensis) in freshwater wetlands in south Florida are closely linked to hydrologic conditions. In the Everglades, seasonally and annually fluctuating surface water levels affect populations of aquatic organisms that alligators consume. Since prey becomes more concentrated when water depth decreases, we hypothesized an inverse relationship between body condition and water depth in the Everglades. On average, condition of adult alligators in the dry season was significantly higher than in the wet season, but this was not the case for juveniles/subadults. The correlation between body condition and measured water depth at capture locations was weak; however, there was a significant negative correlation between the condition and predicted water depth prior to capture for all animals except for spring juveniles/subadults which had a weak positive condition-water depth relationship. Overall, a relatively strong inverse correlation occurred at 10-49 days prior to the capture day, suggesting that current body condition of alligators may depend on feeding opportunities during that period. Fitted regression of body condition on water depth (mean depth of 10 days when condition-water depth correlation was greatest) resulted in a significantly negative slope, except for spring adult females and spring juveniles/subadults for which slopes were not significantly different from zero. Our results imply that water management practices may be critical for alligators in the Everglades since water depth can affect animal condition in a relatively short period of time.
KEYWORDS:Condition index; Alligators; Hydrology; South Florida; Prey abundance
north-central florida; mckinlay river area; crocodylus-johnstoni;
national-park; el-nino; growth; mississippiensis; diet; australia;
abundance |
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(2009) Gabriel, M.C., Kolka, R., Wickman, T., Nater, E. and Woodruff, L. Evaluating the spatial variation of total mercury in young-of-year yellow perch (Perca flavescens), surface water and upland soil for watershed-lake systems within the southern Boreal Shield.
Science of the Total Environment 407(13), 4117-4126. |
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ABSTRACT
The primary objective of this research is to investigate relationships between mercury in upland soil, lake water and fish tissue and explore the cause for the observed spatial variation of THg in age one yellow perch (Perca flavescens) for ten lakes within the Superior National Forest. Spatial relationships between yellow perch THg tissue concentration and a total of 45 watershed and water chemistry parameters were evaluated for two separate years: 2005 and 2006. Results show agreement with other studies where watershed area, lake water pH, nutrient levels (specifically dissolved NO3--N) and dissolved iron are important factors controlling and/or predicting fish THg level. Exceeding all was the strong dependence of yellow perch THg level on soil A-horizon THg and, in particular, soil O-horizon THg concentrations (Spearman rho = 0.81). Soil B-horizon THg concentration was significantly correlated (Pearson r = 0.75) with lake water THg concentration. Lakes surrounded by a greater percentage of shrub wetlands (peatlands) had higher fish tissue THg levels, thus it is highly possible that these wetlands are main locations for mercury methylation. Stepwise regression was used to develop empirical models for the purpose of predicting the spatial variation in yellow perch THg over the studied region. The 2005 regression model demonstrates it is possible to obtain good prediction (up to 60% variance description) of resident yellow perch THg level using upland soil O-horizon THg as the only independent variable. The 2006 model shows even greater prediction (r(2)=0.73, with an overall 10 ng/g [tissue, wet weight] margin of error), using lake water dissolved iron and watershed area as the only model independent variables. The developed regression models in this study can help with interpreting THg concentrations in low trophic level fish species for untested lakes of the greater Superior National Forest and surrounding Boreal ecosystem.
KEYWORDS:Yellow perch; Total mercury; Boreal ecosystem; Watersheds; Regression
modeling
dissolved organic-matter; nova-scotia; methylmercury concentrations;
environmental-factors; florida everglades; kejimkujik-park; methyl
mercury; ontario lakes; national-park; fish |
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(2009) Gaiser, E. Periphyton as an indicator of restoration in the Florida Everglades. Ecological Indicators 9(S37-S45). |
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ABSTRACT
Periphyton communities dominate primary production in much of the Florida Everglades wetland and therefore contribute to soil production, ecosystem metabolism and secondary production as well as the composition of dependent communities. Decades of research in the Everglades have supported research findings from other wetland types that cumulatively show that periphyton communities respond very rapidly to alterations in the two dominant drivers of wetland structure and function-hydrology and water quality. Hydrology controls periphyton productivity and composition by regulating moisture availability, substrate types available for colonization and supply of nutrients. Nutrients, particularly the limiting nutrient in this system, phosphor-us (P), control levels of production and community composition. Because periphyton communities arc well-established to be related to hydrology and water quality, an indicator was developed based on three periphyton attributes: abundance, quality (i.e., nutrient content) and community composition. This assessment tool offers a qualitative assessment of ecosystem response to potential changes in management activities at a time scale appropriate for active management. An example is provided of how the indicator can be used to assess the current water quality and hydrological conditions from high-density spatial surveys. Detected patterns of deterioration align with expectations derived from model predictions and known sources of nutrients and unnatural hydrologic regimes. If employed adaptively, in ecosystem management, this tool can be used to both detect and react to change before the system has been irreparably altered.
KEYWORDS:Periphyton; Everglades; Assessment; Algae; Phosphorus
community structure; water-quality; southern everglades; nutrient
retention; phosphorus; usa; responses; patterns; wetland; mats |
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(2009) Gandiaga, S., Volin, J.C., Kruger, E.L. and Kitajima, K. Effects of hydrology on the growth and physiology of an invasive exotic, Lygodium microphyllum (Old World climbing fern). Weed Research 49(3), 283-290. |
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ABSTRACT
We conducted a glasshouse study to examine effects of hydrology on the growth and physiology of Lygodium microphyllum (Old World climbing fern), an invasive exotic that is rapidly colonising forested wetlands in Florida, USA. We assessed the fern's growth and physiological responses to three hydrological treatments - flood, drought and field capacity. To further explore the physiology of the treatment responses of L. microphyllum, we also sprayed each plant with gibberellic acid, paclobutrazol (gibberellin inhibitor) or a water control solution (at a rate of 5 mL three times per week) using a 3 x 3 factorial design. Flooding reduced relative growth rate by 55%, whereas periodic exposure of ferns to a soil water potential of -1 MPa did not affect growth or physiology. Flooding led to substantial decreases in specific leaf area and area-based rates of pinna photosynthesis, resulting in a 64% lower rate of photosynthesis per unit pinna mass. Application of growth regulators had no effect on fern growth, morphology or physiology. Even though flooding substantially reduced growth, L. microphyllum still showed a positive relative growth rate after > 2 months of inundated soils. This apparent hydrological plasticity is likely a contributing factor to the introduced fern's widespread establishment across a range of plant communities within the Florida Everglades ecosystem. Short-term manipulation of site hydrology does not appear to be an effective management option. Consequently, this has considerable implications for the Everglades, which is undergoing a 30-year system-wide hydrological restoration.
KEYWORDS:relative growth rate; growth analysis; flooding; growth regulator;
invasive species; alien; exotic species; gibberellic acid; paclobutrazol
gibberellic-acid; biomass allocation; oxygen deficiency; gas-exchange;
water-stress; paclobutrazol; metabolism; responses; ethylene; plants |
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(2009) Grunwald, S., Daroub, S.H., Lang, T.A. and Diaz, O.A. Tree-based modeling of complex interactions of phosphorus loadings and environmental factors. Science of the Total Environment 407(12), 3772-3783. |
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ABSTRACT
Phosphorus (P) enrichment has been observed in the historic oligotrophic Greater Everglades in Florida mainly due to P influx from upstream, agriculturally dominated, low relief drainage basins of the Everglades Agricultural Area (EAA). Our specific objectives were to: (1) investigate relationships between various environmental factors and P loads in 10 farm basins within the EAA, (2) identify those environmental factors that impart major effects on P loads using three different tree-based modeling approaches. and (3) evaluate predictive models to assess P loads. We assembled thirteen environmental variable sets for all 10 sub-basins characterizing water level management, cropping practices, soils, hydrology, and farm-specific properties. Drainage flow and P concentrations were measured at each sub-basin outlet from 1992-2002 and aggregated to derive monthly P loads. We used three different tree-based models including single regression trees (ST), committee trees in Bagging (CTb) and ARCing (CTa) modes and ten-fold cross-validation to test prediction performances. The monthly P loads (MPL) during the monitoring period showed a maximum of 2528 kg (mean: 103 kg) and maximum monthly unit area P loads (UAL) of 4.88 kg P ha(-1) (mean: 0.16 kg P ha(-1)). Our results suggest that hydrologic/water management properties are the major controlling variables to predict MPL and UAL in the EAA. Tree-based modeling was successful in identifying relationships between P loads and environmental predictor variables on 10 farms in the EAA indicated by high R-2 (> 0.80) and low prediction errors. Committee trees in ARCing mode generated the best performing models to predict P loads and P loads per unit area. Tree-based models had the ability to analyze complex, non-linear relationships between P loads and multiple variables describing hydrologic/water management, cropping practices, soil and farm-specific properties within the EAA.
KEYWORDS:Phosphorus; Phosphorus loads; Water quality; Regression trees;
Committee trees; Everglades Agricultural Area
everglades agricultural area; regression trees; neural-networks; random
forests; united-states; water; florida; land; classification; management |
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(2009) Harvey, J.W. and McCormick, P.V. Groundwater's significance to changing hydrology, water chemistry, and biological communities of a floodplain ecosystem, Everglades, South Florida, USA. Hydrogeology Journal 17(1), 185-201. |
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ABSTRACT
The Everglades ( Florida, USA) is one of the world's larger subtropical peatlands with biological communities adapted to waters low in total dissolved solids and nutrients. Detecting how the pre-drainage hydrological system has been altered is crucial to preserving its functional attributes. However, reliable tools for hindcasting historic conditions in the Everglades are limited. A recent synthesis demonstrates that the proportion of surface-water inflows has increased relative to precipitation, accounting for 33% of total inputs compared with 18% historically. The largest new source of water is canal drainage from areas of former wetlands converted to agriculture. Interactions between groundwater and surface water have also increased, due to increasing vertical hydraulic gradients resulting from topographic and water-level alterations on the otherwise extremely flat landscape. Environmental solute tracer data were used to determine groundwater's changing role, from a freshwater storage reservoir that sustained the Everglades ecosystem during dry periods to a reservoir of increasingly degraded water quality. Although some of this degradation is attributable to increased discharge of deep saline groundwater, other mineral sources such as fertilizer additives and peat oxidation have made a greater contribution to water-quality changes that are altering mineral-sensitive biological communities.
KEYWORDS:Coastal aquifers; Contamination; Groundwater/surface-water relations;
Paleohydrology; USA; Wetlands; Everglades
northern everglades; okavango delta; surface-water; vegetation;
botswana; peatland; minnesota; patterns; exchange; wetlands |
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(2009) Harvey, J.W., Schaffranek, R.W., Noe, G.B., Larsen, L.G., Nowacki, D.J. and O'Connor, B.L. Hydroecological factors governing surface water flow on a low-gradient floodplain. Water Resources Research 45( |
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ABSTRACT
Interrelationships between hydrology and aquatic ecosystems are better understood in streams and rivers compared to their surrounding floodplains. Our goal was to characterize the hydrology of the Everglades ridge and slough floodplain ecosystem, which is valued for the comparatively high biodiversity and connectivity of its parallel-drainage features but which has been degraded over the past century in response to flow reductions associated with flood control. We measured flow velocity, water depth, and wind velocity continuously for 3 years in an area of the Everglades with well-preserved parallel-drainage features (i.e., 200-m wide sloughs interspersed with slightly higher elevation and more densely vegetated ridges). Mean daily flow velocity averaged 0.32 cm s(-1) and ranged between 0.02 and 0.79 cm s(-1). Highest sustained velocities were associated with flow pulses caused by water releases from upstream hydraulic control structures that increased flow velocity by a factor of 2-3 on the floodplain for weeks at a time. The highest instantaneous measurements of flow velocity were associated with the passage of Hurricane Wilma in 2005 when the inverse barometric pressure effect increased flow velocity up to 5 cm s(-1) for several hours. Time-averaged flow velocities were 29% greater in sloughs compared to ridges because of marginally higher vegetative drag in ridges compared to sloughs, which contributed modestly (relative to greater water depth and flow duration in sloughs compared to ridges) to the predominant fraction (86%) of total discharge through the landscape occurring in sloughs. Univariate scaling relationships developed from theory of flow through vegetation, and our field data indicated that flow velocity increases with the square of water surface slope and the fourth power of stem diameter, decreases in direct proportion with increasing frontal area of vegetation, and is unrelated to water depth except for the influence that water depth has in controlling the submergence height of vegetation that varies vertically in its architectural characteristics. In the Everglades the result of interactions among controlling variables was that flow velocity was dominantly controlled by water surface slope variations responding to flow pulses more than spatial variation in vegetation characteristics or fluctuating water depth. Our findings indicate that floodplain managers could, in addition to managing water depth, manipulate the frequency and duration of inflow pulses to manage water surface slope, which would add further control over flow velocities, water residence times, sediment settling, biogeochemical transformations, and other processes that are important to floodplain function.
KEYWORDS:through emergent vegetation; everglades national-park;
doppler-velocimeter data; riparian vegetation; florida everglades;
roughness coefficients; submerged vegetation; circular-cylinder; river;
wetlands |
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(2009) Harwell, M.C. and Sharfstein, B. Submerged aquatic vegetation and bulrush in Lake Okeechobee as indicators of greater Everglades ecosystem restoration. Ecological Indicators 9(S46-S55). |
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ABSTRACT
Lake Okeechobee, Florida, located in the middle of the larger Kissimmee River-Lake Okeechobee-Everglades ecosystem in South Florida, serves a variety of ecosystem and water management functions including fish and wildlife habitat, flood control, water supply, and source water for environmental restoration. As a result, the ecological status of Lake Okeechobee plays a significant role in defining the overall success of the greater Everglades ecosystem restoration initiative. One of the major ecological indicators of Lake Okeechobee condition focuses on the near-shore and littoral zone regions as characterized by the distribution and abundance of submerged aquatic vegetation (SAV) and giant bulrush (Scirpus californicus (C.A. Mey.) Steud.). The objective of this study is to present a stoplight restoration report card communication system, common to all 11 indicators noted in this special journal issue, as a means to convey the status of SAV and bulrush in Lake Okeechobee. The report card could be used by managers, policy makers, scientists and the public to effectively evaluate and distill information about the ecological status in South Florida. Our assessment of the areal distribution of SAV in Lake Okeechobee is based on a combination of empirical SAV monitoring and output from a SAV habitat suitability model. Bulrush status in the lake is related to a suitability index linked to adult survival and seedling establishment metrics. Overall, presentation of these performance metrics in a stoplight format enables an evaluation of how the status of two major components of Lake Okeechobee relates to the South Florida restoration program, and how the status of the lake influences restoration efforts in South Florida.
KEYWORDS:Ecosystem indicators; Giant bulrush; Habitat integrator; Lake
Okeechobee; SAV; Scirpus californicus; South Florida
large subtropical lake; florida; management |
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(2009) Heithaus, M.R., Delius, B.K., Wirsing, A.J. and Dunphy-Daly, M.M. Physical factors influencing the distribution of a top predator in a subtropical oligotrophic estuary. Limnology and Oceanography 54(2), 472-482. |
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ABSTRACT
We used longline fishing to determine the effects of distance from the ocean, season, and short-term variation in abiotic conditions on the abundance of juvenile bull sharks (Carcharhinus leucas) in an estuary of the Florida Everglades, U.S.A. Logistic regression revealed that young-of-the-year sharks were concentrated at a protected site 20 km upstream and were present in greater abundance when dissolved oxygen (DO) levels were high. For older juvenile sharks (age 1+), DO levels had the greatest influence on catch probabilities followed by distance from the ocean; they were most likely to be caught at sites with > 3.5 mg L-1 DO and on the main branch of the river 20 km upstream. Salinity had a relatively small effect on catch rates and there were no seasonal shifts in shark distribution. Our results highlight the importance of considering DO as a possible driver of top predator distributions in estuaries, even in the absence of hypoxia. In Everglades estuaries hydrological drivers that affect DO levels (e.g., groundwater discharge, modification of primary productivity through nutrient fluxes) will be important in determining shark distributions, and the effects of planned ecosystem restoration efforts on bull sharks will not simply be mediated by changing salinity regimes and the location of the oligohaline zone. More generally, variation in DO levels could structure the nature and spatiotemporal pattern of top predator effects in the coastal Everglades, and other tropical and subtropical estuaries, because of interspecific variation in reliance on DO within the top predator guild.
KEYWORDS:sharks carcharhinus-leucas; juvenile bull sharks; florida-everglades;
rectal gland; hypoxia; plasma; usa; consequences; management; ecosystem |
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(2009) Herbert, D.A. and Fourqurean, J.W. Phosphorus Availability and Salinity Control Productivity and Demography of the Seagrass Thalassia testudinum in Florida Bay. Estuaries and Coasts 32(1), 188-201. |
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ABSTRACT
Biomass, net primary productivity (NPP), foliar elemental content, and demography of Thalassia testudinum were monitored in populations from five sites across Florida Bay beginning in January 2001. Sites were selected to take advantage of the spatial variability in phosphorus (P) availability and salinity climates across the bay. Aboveground biomass and NPP of T. testudinum were determined five to six times annually. Short-shoot demography, belowground biomass, and belowground NPP were assessed from a single destructive harvest at each site and short-shoot cohorts were estimated from leaf scar counts multiplied by site-specific leaf production rates. Biomass, relative growth rate (RGR), and overall NPP were positively correlated with P availability. Additionally, a positive correlation between P availability and the ratio of photosynthetic to non-photosynthetic biomass suggests that T. testudinum increases allocation to aboveground biomass as P availability increases. Population turnover increased with P availability, evident in positive correlations of recruitment and mortality rates with P availability. Departures from seasonally modeled estimates of RGR were found to be influenced by salinity, which depressed RGR when below 20 psu or above 40 psu. Freshwater management in the headwaters of Florida Bay will alter salinity and nutrient climates. It is becoming clear that such changes will affect T. testudinum, with likely feedbacks on ecosystem structure, function, and habitat quality.
KEYWORDS:Seagrass; Productivity; Demography; Phosphorus; Salinity; Long-term
monitoring
turtle grass; posidonia-oceanica; nutrient availability; south florida;
growth; nitrogen; reconstruction; everglades; abundance; dynamics |
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(2009) Herring, G., Gawlik, D.E. and Rumbold, D.G. Feather mercury concentrations and physiological condition of great egret and white ibis nestlings in the Florida Everglades. Science of the Total Environment 407(8), 2641-2649. |
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ABSTRACT
Mercury contamination in the Florida Everglades has reportedly played a role in the recent decline of wading birds, although no studies have identified a mechanism leading to population-level effects. We assessed feather mercury levels in great egret (Ardea alba; n=91) and white ibis (Eudocimus albus; n=46) nestlings at breeding colonies in the Florida Everglades during a year (2006) with excellent breeding conditions (characterized by hydrology leading to concentrated prey) and a year with below average breeding conditions (2007). We also assessed the physiological condition of those nestlings based on levels of plasma and fecal corticosterone metabolites, and stress proteins 60 and 70. Mercury levels were higher in both species during the good breeding condition year (great egret=6.25 mu g/g +/- 0.81 SE, white ibis = 1.47 mu g/g +/- 0.41 SE) and lower in the below average breeding year (great egret=1.60 mu g/g +/- 0.11 SE, white ibis=0.20 mu g/g +/- 0.03 SE). Nestlings were in better physiological condition in 2006, the year with higher feather mercury levels. These results support the hypothesis that nestlings are protected from the harmful effects of mercury through deposition of mercury in growing feathers. We found evidence to suggest shifts in diets of the two species, as a function of prey availability, thus altering their exposure profiles. However, we found no evidence to suggest they respond differently to mercury exposure.
KEYWORDS:Egrets; Everglades; Ibis; Mercury; Physiological condition; Wetlands
stress-proteins; methyl mercury; ardea-albus; methylmercury
concentrations; constructed wetland; southern florida; eudocimus-albus;
nesting effort; wading birds; common loons |
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(2009) Ho, D.T., Engel, V.C., Variano, E.A., Schmieder, P.J. and Condon, M.E. Tracer studies of sheet flow in the Florida Everglades.
Geophysical Research Letters 36( |
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ABSTRACT
Information on sheet flow patterns in the marsh ridge and slough habitat of the Florida Everglades is scarce, primarily because of difficulty in taking measurements across large enough spatial scales in such a heterogeneous environment. As part of the Everglades Tracer Release Experiment (EverTREx), two SF6 tracer releases were conducted to measure sheet flow in relatively intact ridge and slough habitats. The first was a pilot experiment that allowed the analytical equipment to be tested in the Everglades, and yielded some preliminary, coarse-scale measurements of advection and dispersion in multiple sloughs. In the second experiment, higher-resolution measurements of tracer distributions in a single slough showed that the mean advection ranged from 0.08 to 0.15 cm s(-)1, while longitudinal dispersion ranged from 3.7 x 10(2) to 2.6 x 10(3) cm(2) s(-1). Citation: Ho, D. T., V. C. Engel, E. A. Variano, P. J. Schmieder, and M. E. Condon (2009), Tracer studies of sheet flow in the Florida Everglades, Geophys. Res. Lett., 36, L09401, doi:10.1029/2009GL037355.
KEYWORDS:longitudinal dispersion; release experiment; slough landscape;
national-park; sf6 tracer; vegetation; transport; wetland; model; ridge |
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(2009) Hoang, T.C. and Rand, G.M. Exposure routes of copper: Short term effects on survival, weight, and uptake in Florida apple snails (Pomacea paludosa). Chemosphere 76(3), 407-414. |
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ABSTRACT
The uptake and effects (Survival, weight) of copper (Cu) on Florida apple snails (Pomacea paludosa) via exposures to copper-enriched agricultural soil-water and water-only treatments were investigated. Soils were collected from citrus sites in south Florida and flooded with laboratory freshwater for 14 d. Neonate apple snails (<= 96-h-old) were then exposed to either Cu from a soil-overlying water (i.e., flooded agricultural soils) treatment or overlying water-only (i.e., equilibrated overlying water produced from 14 d flooding of agriculture soils) treatment for 14 d under standard laboratory conditions. Survival, weight (dry, wet), and whole body Cu uptake were measured. Copper exposure via soil-water exposures resulted in higher mortality and whole body Cu uptake than water-only exposures, indicating Cu uptake from soils. However, snail wet and dry weights were higher in soil-water treatments than in water-only treatments. Micronutrients from soils may be consumed by snails increasing weights. Survival, apple snail dry weight, and whole body Cu concentrations were significantly correlated with soil and water Cu concentrations in soil-water treatments. Survival was significantly correlated with the concentration of Cu(CO3)(2)(2-) in water-only treatments. This suggests that Cu(CO3)(2)(2-) is toxic to apple snails. Whole body Cu concentrations were higher in surviving snails than dead snails, suggesting that apple snails have the ability to detoxify accumulated Cu (e.g., through metallothionein induction, granules).
KEYWORDS:Soil exposure; Water exposure; Copper bioavailability; Copper uptake;
Pomacea paludosa; Comprehensive Everglades Restoration Plan (CERP)
biotic ligand model; lymnaea-stagnalis; phosphate granules; acute
toxicity; helix-aspersa; food-chain; bioaccumulation; metals; soil;
metallothionein |
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(2009a) Hoang, T.C., Schuler, L.J., Rogevich, E.C., Bachman, P.M., Rand, G.M. and Frakes, R.A. Copper Release, Speciation, and Toxicity Following Multiple Floodings of Copper Enriched Agriculture Soils: Implications in Everglades Restoration. Water Air and Soil Pollution 199(1-4), 79-93. |
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ABSTRACT
This study characterizes the effects of water-soil flooding volume ratio and flooding time on copper (Cu) desorption and toxicity following multiple floodings of field-collected soils from agricultural sites acquired under the Comprehensive Everglades Restoration Plan (CERP) in south Florida. Soils from four field sites were flooded with three water-soil ratios (2, 4, and 6 [water] to 1 [soil]) and held for 14 days to characterize the effects of volume ratio and flooding duration on Cu desorption (volume ratio and flooding duration study). Desorption of Cu was also characterized by flooding soils four times from seven field sites with a volume ratio of 2 (water) to 1 (soil) (multiple flooding study). Acute toxicity tests were also conducted using overlying waters from the first flooding event to characterize the effects of Cu on the survival of fathead minnows (Pimephales promelas), cladocerans (Daphnia magna), amphipods (Hyalella azteca), midges (Chironomus tentans), duckweed (Lemna minor), and Florida apple snails (Pomacea paludosa). Acute tests were also conducted with D. magna exposed to overlying water from the second and third flooding events. Results indicate that dissolved Cu concentrations in overlying water increased with flooding duration and decreased with volume ratio. In the multiple flooding study, initial Cu concentrations in soils ranged from 5 to 223 mg/kg (dw) and were similar to Cu concentration after four flooding events, indicating retention of Cu in soils. Copper desorption was dependent on soil Cu content and soil characteristics. Total Cu concentration in overlying water (Cu-w) was a function of dissolved organic carbon (DOC), alkalinity, and soil Cu concentration (Cu-s): log(Cu-w) = 1.2909 + 0.0279 (DOC) + 0.0026 (Cu-s) -aEuro parts per thousand 0.0038 (alkalinity). The model was validated and highly predictive. Most of the desorbed Cu in the water column complexed with organic matter in the soils and accounted for 99% of the total dissolved Cu. Although total dissolved Cu concentrations in overlying water did not significantly decrease with number of flooding events, concentrations of free Cu2+ increased with the number of flooding events, due to a decrease in DOC concentrations. The fraction of bioavailable Cu species (Cu2+, CuOH+, CuCO3) was also less than 1% of the total Cu. Overlying water from the first flooding event was only acutely toxic to the Florida apple snail from one site. However, overlying water from the third flooding of six out of seven soils was acutely toxic to D. magna. The decrease in DOC concentrations and increase in bioavailable Cu2+ species may explain the changes in acute toxicity to D. magna. Results of this study reveal potential for high Cu bioavailability (Cu2+) and toxicity to aquatic biota overtime in inundated agricultural lands acquired under the CERP.
KEYWORDS:Copper release; Speciation; Bioavailability; Toxicity; Flooding; Soils;
Everglades restoration
biotic ligand model; minnows pimephales-promelas; dissolved
organic-carbon; florida apple snail; fathead minnows; daphnia-magna;
pomacea-paludosa; water hardness; sandy soils; pH |
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(2009b) Hotaling, A.S., Martin, J. and Kitchens, W.M. Estimating Transition Probabilities among Everglades Wetland Communities Using Multistate Models. Wetlands 29(4), 1224-1233. |
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ABSTRACT
In this study we were able to provide the first estimates of transition probabilities of wet prairie and slough vegetative communities in Water Conservation Area 3A (WCA3A) of the Florida Everglades and to identify the hydrologic variables that determine these transitions. These estimates can be used in management models aimed at restoring proportions of wet prairie and slough habitats to historical levels in the Everglades. To determine what was driving the transitions between wet prairie and slough communities we evaluated three hypotheses: seasonality, impoundment, and wet and dry year cycles using likelihood-based Multistate models to determine the main driver of wet prairie conversion in WCA3A. The most parsimonious model included the effect of wet and dry year cycles on vegetative community conversions. Several ecologists have noted wet prairie conversion in southern WCA3A but these are the first estimates of transition probabilities among these Community types. In addition, to being useful for management of the Everglades we believe that our framework can be used to address management questions in other ecosystems.
KEYWORDS:adaptive management; community dynamics; restoration
florida everglades; snail kite; conservation; population; management;
vegetation; survival; movement; dynamics |
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(2009) Inglett, P.W., D'Angelo, E.M., Reddy, K.R., McCormick, P.V. and Hagerthey, S.E. Periphyton nitrogenase activity as an indicator of wetland eutrophication: spatial patterns and response to phosphorus dosing in a northern Everglades ecosystem. Wetlands Ecology and Management 17(2), 131-144. |
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ABSTRACT
The use of periphyton nitrogenase activity (biological N-2 fixation) as an indicator of wetland P impact was assessed using patterns of nutrient content (C, N, P, Ca, Mg, K, Fe, and Mn) and acetylene reduction (AR) in floating cyanobacterial periphyton mat (metaphyton) communities of a P-enriched portion of the Florida Everglades, USA (Water Conservation Area-2A, WCA-2A). Spatial patterns of nutrients indicate the enrichment of floating mat periphyton N, P, Fe, and K, and the reduction of Mn and TN:TP in enriched marsh areas. In highly enriched areas, floating mat periphyton AR was approximately threefold greater than that in less enriched, interior marsh zones. Multiple regression models indicated AR dependence on P in eutrophicWCA-2A areas while the AR of more interior marsh periphyton mats was more closely related to tissue levels of Ca and Fe. Nitrogenase activity of floating mat periphyton from P-loaded mesocosms revealed a significant enhancement of N-2 fixation in samples receiving approximately 2-3 mg P m(-2) of cumulative P dosing or with biomass TP content of 100-300 mg kg(-1). At P contents above the optimum, mat periphyton AR was suppressed possibly as a result of changes in species composition or increased levels of NH4+. After 3 years of dosing, consistently high AR occurred only at low rates of P enrichment (0.4-0.8 g P m(-2) yr(-1)), and the patterns appeared to be seasonal. These findings agree with the hypothesis that P availability is a key determinant of nitrogenase activity in aquatic systems, and thus, may support the use of periphyton nitrogenase to indicate P impacts in P-limited systems. These results also demonstrate the potential existence of a P threshhold for biogeochemical alteration of periphyton mat function in the Everglades, and that cumulative loading of limiting nutrients (i.e., P), rather than instantaneous concentrations, should be considered when evaluating nutrient criteria.
KEYWORDS:Metaphyton; Cyanobacterial mat; Nitrogen fixation; Phosphorus;
Acetylene reduction
florida everglades; fixation; enrichment; nutrients; gradient; soil;
communities; lakes; mats |
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(2009) Jin, G., Eilts, K., Kelley, T.R. and Webb, J.W. Preliminary water quality assessment of Spunky Bottoms restored wetland.
Journal of Environmental Science and Health Part a-Toxic/Hazardous Substances & Environmental Engineering 44(3), 235-243. |
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ABSTRACT
The approximately 1200-acre "Spunky Bottoms" wetland in Southern Illinois has been undergoing restoration to conditions prior to levying of the Illinois River and draining of adjacent floodplain for intensive agriculture (circa 1900). As part of a long-term water quality impact assessment of this restoration project, baseline water quality monitoring was conducted soon after restoration began. During this baseline/preliminary assessment, water samples were taken every 2-4 weeks from 10 sampling wells and seven surface water sites throughout the wetlands area for a period of 18 months. Measured parameters include nutrients (nitrate (NO3-) and phosphate (PO43-), cations and anions (SO42-, Cl-, Na+, K+, Mg2+, Ca2+) commonly found in surface and well water, trace metals (Al, Cd, Cu, Fe, Mn, Ni, Pb, Se, Zn), total dissolved solids (TDS), pH, and trace organics (triazine herbicides and their metabolites). In general, highest concentrations of ions were found in the southwest and northeast perimeter of the wetland area for both surface and ground water samples. Primarily low concentrations of heavy metals and organic compounds were found throughout the wetland sampling area. Distribution of NO3--N suggests that this restored wetland, even at its infant age, may still contribute to biogeochemical (particularly N) element cycling. Continued monitoring and further research is necessary to determine long-term specific contribution of restored wetland to biogeochemical cycles.
KEYWORDS:Restored wetland; nutrients; cations and anions; trace metals; trace
organics
phosphorus retention; constructed wetland; river-basin; waste-water;
accumulation; restoration; everglades; catchments; vegetation; nutrient |
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(2009) Kadlec, R.H. Wastewater treatment at the Houghton lake wetland: Soils and sediments. Ecological Engineering 35(9), 1333-1348. |
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ABSTRACT
This paper describes the vegetation responses in a very long-running study of the capacity of a natural peatland to remove nutrients from treated wastewater. Data are here presented and analyzed from three decades of full-scale operation, during which large changes in the plant communities occurred. An average of 600,000 m(3) year(-1) of treated wastewater was discharged seasonally (May 1-October 31) to the Porter Ranch peatland near the community of Houghton Lake, Michigan. This discharge was seasonal, commencing no sooner than May 1 and ending no later than October 31. During the winter half-year, treated wastewater was stored at the lagoon site. This water contained 3.5 mg/L of total phosphorus, and 7 mg/L of dissolved inorganic nitrogen (DIN). Nutrients were stored in the 100 ha irrigation area, which removed 94% of the phosphorus (53 metric tons) and 95% of the dissolved inorganic nitrogen. Phosphorus was stored in new biomass, increased soil sorption, and accretion of new soils and sediments, with accretion being dominant. The irrigation area underwent large changes in ecosystem structure, in which the original plant communities were displaced by Typha spp. There was an initial fertilizer response, characterized by much larger standing crops of vegetation, at about triple the crop in control areas. Increased biomass was accompanied by increases in tissue nitrogen and phosphorus content, by factors of two and three, respectively. The plant community shift, from the initial sedge-willow and leatherleaf-bog birch cover types to a cattail-dominant cover type, progressed to a 83-ha area over the 30-year period of record (POR). The interior portion of this new cattail patch became a floating mat. There were large gradients in stem densities and stem heights within the impacted area. The response times of the vegetative community shifts were on the order of 10 years for 63% of the final impact zone development. The grow-in time for development of a new larger standing crop in the discharge zone was also 10 years. The impacted area was stable at the 30-year time, without any further moving fronts. Around the cattail zone, there were fringe areas that contained a mixture of the original cover types intruded by relatively small amounts of cattail.
KEYWORDS:Treatment wetlands; Vegetation; Cattails; Sedges; Woody shrubs;
Duckweed; Litter; Nutrients
phosphorus; everglades |
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(2009a) Kadlec, R.H. and Bevis, F.B. Wastewater treatment at the Houghton Lake wetland: Vegetation response. Ecological Engineering 35(9), 1312-1332. |
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ABSTRACT
This paper describes the sediment and soils responses in a very long-running study of the capacity of a natural peatland to remove nutrients from treated wastewater. Data are here presented and analyzed from three decades of full-scale operation (1978-2007), during which large changes in the wetland soils occurred. An average of 600,000 m(3) y(-1) of treated water was discharged each warm season to the Porter Ranch peatland near the community of Houghton Lake, Michigan. This discharge was seasonal, commencing no sooner than May 1 and ending no later than October 31. During the winter half-year, treated wastewater was stored at the lagoon site. This water contained 3.5 mg/L of total phosphorus, and 7 mg/L of dissolved inorganic nitrogen. Nutrients were stored in the 100 ha irrigation area, which removed 94% of the phosphorus (53 t) and 95% of the dissolved inorganic nitrogen. Phosphorus was stored in new biomass, increased soil sorption, and accretion of new soils and sediments, with accretion being dominant. Peat probings, water level increases and topographical surveys established quantitative measures of soil accretion. Over 30 cm of new soil developed, in which nutrient storage occurred. Phosphorus concentrations in the new soil were approximately 2000 mg P/kg, and the nitrogen concentration was 2-3%DW. The removal of TSS was effective, but minor in comparison to the internal generation and cycling of produced particulates. Later in the project history, the interior portion of impacted area became a floating mat. Sedimentation processes then occurred with no exposure to above-mat detrital processes. Trace element analyses showed no appreciable accumulation of heavy metals, other than the calcium and iron that characterized the antecedent wetland and the incoming water. Biomass cycling models were found to produce reasonable estimates of the measured nutrient accumulations. The light loadings of nutrients to this system produced dramatic effects in the ecosystem, but were lower than the range seen in some other treatment wetlands. Insufficient nitrogen was added to support the new biomass, and nitrogen fixation was identified as a possible compensatory mechanism.
KEYWORDS:Treatment wetlands; Peat; Accretion; Nutrients
everglades; model; phosphorus; accumulation; transport; accretion;
effluent |
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(2009) Keddy, P.A. Thinking Big: A Conservation Vision for the Southeastern Coastal Plain of North America. Southeastern Naturalist 8(2), 213-226. |
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ABSTRACT
Maps of wild or roadless areas in North America show that most lie west of the Mississippi River. The Everglades is one exception. Yet there are others. Using existing data, I draw attention to four large areas in the southeast that are worthy of national as well as regional attention. These four (Eglin: 187,000+ ha; Apalachicola: 228,000+ ha; Okefenokee-Oceola: 289,000+ ha; De Soto: 200,000+ ha) have nearby lands that offer the potential to expand the total protected territory for each area to well beyond 500,000 ha. From the North American perspective, these areas are essential elements of a national conservation plan. These areas urgently need (I) land acquisition to link with nearby protected lands and establish ecologically meaningful boundaries, (2) restoration of natural forces (particularly flooding and fire), and (3) forestry practices focused upon restoration.
KEYWORDS:plant; deer |
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(2009) Knickerbocker, C.M., Leitholf, S., Stephens, E.L., Keellings, D.J., Laird, H., Anderson, C.J.R., Fauth, J.E. and Quintana-Ascencio, P.F. Tree Encroachment of A Sawgrass (Cladlum jamaicense) Marsh within an Increasingly Urbanized Ecosystem. Natural Areas Journal 29(1), 15-26. |
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ABSTRACT
Fire suppression and altered water drainage often change community structure and species composition in human-dominated ecosystems. We describe the decline of sawgrass marshes between 1940 and 2002, and assess the current condition of remnant marshes within the MacKay Tract, an isolated wetland embedded within rapidly developing eastern Orlando, Florida. We tested the correlation between live sawgrass and presence of adult hardwood trees and seedlings (primarily red maple, Acer rubrum) and describe vegetation in plots with different levels of tree encroachment. Total area occupied by open sawgrass in the MacKay Tract has declined dramatically the last 60 years, in 2006, open sawgrass comprised only 12% of the area covered in 1940. Tree basal cover was negatively associated with live sawgrass and positively related to red maple seedling density, but not associated with dead sawgrass tussocks. Sawgrass was positively correlated with the second axis of a non-metric multidimensional scaling ordination on understory plant assemblage, while red maple seedlings and several species associated with disturbed areas were significantly negatively cot-related with this axis. Another nine plant species were positively correlated with the first axis, while Osmunda cinnamomea (cinnamon fern) was negatively associated with it. We suggest that woody species are continuing to colonize what is left of the sawgrass marsh. Without intervention (e.g., restoring hydrologic flow and fire), the sawgrass (Cladium jamaicense Crantz) area within the marsh will continue being replaced by woody and exotic species.
KEYWORDS:drainage; fire suppression; Florida; marshes; Orlando; red maple;
sawgrass; urban ecosystems; wetlands
cladium-jamaicense; florida everglades; willamette valley;
typha-domingensis; wetland; fire; diversity; invasion; restoration;
communities |
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(2009) Knight, A. and Brower, L.P. The Influence of Eastern North American Autumnal Migrant Monarch Butterflies (Danaus plexippus L.) on Continuously Breeding Resident Monarch Populations in Southern Florida. Journal of Chemical Ecology 35(7), 816-823. |
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ABSTRACT
In Florida, the eastern North American population of the monarch butterfly exhibits geographic variability in population structure and dynamics. This includes the occurrence of migrants throughout the peninsula during the autumnal migration, occasional overwintering clusters that form along the Gulf Coast, remigrants from Mexico that breed in north-central Florida during the spring, and what have been assumed to be year-round, resident breeding populations in southern Florida. The work reported here focused on two monarch populations west of Miami and addressed four questions: Are there permanent resident populations of monarchs in southern Florida? Do these breed continuously throughout the year? Do they receive northern monarchs moving south during the autumn migration? Do they receive overwintered monarchs returning via Cuba or the Yucatan during the spring remigration from the Mexican overwintering area? Monthly collections and counts of spermatophores in the bursa copulatrices of females established that a resident population of continuously breeding monarchs exists year-round in southern Florida. It was determined through cardenolide fingerprinting that most of the butterflies had bred on the local southern Florida milkweed species, Asclepias curassavica. During the autumn migration period, however, some monarchs had fed on the northern milkweed, Asclepias syriaca. It appears that instead of migrating to Mexico, these individuals travel south through peninsular Florida, break diapause, mate with and become incorporated into the resident breeding populations. None of the monarchs captured in spring had the A. syriaca cardenolide fingerprint, which is evidence against the southern Florida populations receiving overwintered remigrants from Cuba, Central America or Mexico.
KEYWORDS:Asclepias syriaca; A. curassavica; Biogeography; Cardenolide; Thin
layer chromatography fingerprints; Danainae; Migration; Milkweed;
Population biology; Resident breeding populations; Everglades;
Lepidoptera
asclepias-syriaca-l; common milkweed; l lepidoptera; nymphalidae;
mexico; temperature; queen; migration; gilippus; danaidae |
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(2009) Lai, D.Y. and Lam, K.C. Phosphorus sorption by sediments in a subtropical constructed wetland receiving stormwater runoff.
Ecological Engineering 35(5), 735-743. |
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ABSTRACT
This study investigated the potential of using a mixture of fishpond bund material, completely decomposed granite and river sand as substrate in a constructed wetland for phosphorus removal. Core samples were collected from the newly constructed Hong Kong Wetland Park (HKWP) receiving influent stormwater from a nearby new town, and batch incubation experiments were conducted to determine the P sorption characteristics of sediments. The HKWP sediments adsorbed the majority of available P in the initial 20 min of incubation, with a first-order rate constant of 1.01-2.11 h(-1). Sediments in the reedbeds and freshwater marshes possessed a great capacity for P adsorption with the high Langmuir sorption maxima (478-858 mg kg(-1)) and Freundlich adsorption constants (417-672 L kg(-1)) obtained, attributable to the high amorphous iron and aluminium concentrations compared to other constructed wetlands. Moreover, sediment equilibrium P concentrations were generally low (4.6-23.6 mu g L-1), facilitating a net P adsorption by sediments under moderate P loadings. Yet, the amount of P adsorbed by the HKWP sediments was limited by the low ambient porewater P concentrations and there was even a risk of P desorption when sediments in the freshwater marshes were resuspended into the water column. While substrates in the HKWP demonstrated a great potential for P adsorption, consideration should also be given to P loadings in influent water to fully utilize the P sorption capacity of sediments and enhance the P removal efficiency of constructed wetlands.
KEYWORDS:Adsorption; Constructed wetland; Hong Kong; Kinetics; Phosphorus;
Sediment; Stormwater runoff
waste-water treatment; adsorption characteristics; phosphate
adsorption; retention capacity; filter media; soils; removal;
everglades; desorption; municipal |
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(2009) Larsen, L.G., Harvey, J.W. and Crimaldi, J.P. Morphologic and transport properties of natural organic floc.
Water Resources Research 45 (W01410, doi:10.1029/2008WR006990), 13p. |
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ABSTRACT
The morphology, entrainment, and settling of suspended aggregates ("floc'') significantly impact fluxes of organic carbon, nutrients, and contaminants in aquatic environments. However, transport properties of highly organic floc remain poorly understood. In this study detrital floc was collected in the Florida Everglades from two sites with different abundances of periphyton for use in a settling column and in racetrack flume entrainment experiments. Although Everglades flocs are similar to other organic aggregates in terms of morphology and settling rates, they tend to be larger and more porous than typical mineral flocs because of biostabilization processes and relatively low prevailing shear stresses typical of wetlands. Flume experiments documented that Everglades floc was entrained at a low bed shear stress of 1.0 x 10(-2) Pa, which is considerably smaller than the typical entrainment threshold of mineral floc. Because of similarities between Everglades floc and other organic floc populations, floc transport characteristics in the Everglades typify the behavior of floc in other organic-rich shallow-water environments. Highly organic floc is more mobile than less organic floc, but because bed shear stresses in wetlands are commonly near the entrainment threshold, wetland floc dynamics are often transport-limited rather than supply limited. Organic floc transport in these environments is therefore governed by the balance between entrainment and settling fluxes, which has implications for ecosystem metabolism, materials cycling, and even landscape evolution.
KEYWORDS:fluvial suspended sediment; fine-grained sediments; bottom
boundary-layer; settling velocity; in-situ; marine snow; size
distributions; aquatic ecosystems; vertical transport; cohesive sediment |
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(2009a) Larsen, L.G., Harvey, J.W. and Crimaldi, J.P. Predicting bed shear stress and its role in sediment dynamics and restoration potential of the Everglades and other vegetated flow systems. Ecological Engineering 35(12), 1773-1785. |
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ABSTRACT
Entrainment of sediment by flowing water affects topograph ability, and nutrient cycling in vegetated floodplains and wetlands, impacting ecosystem evolution and the success of restoration projects. Nonetheless, restoration managers lack simple decision-support tools for predicting shear stresses and sediment redistribution potential in different vegetation communities. Using a field-validated numerical model, we developed state-space diagrams that provide these predictions over a range of water-surface slopes, depths, and associated velocities in Everglades ridge and slough vegetation communities. Diminished bed shear stresses and a consequent decrease in bed sediment redistribution are hypothesized causes of a recent reduction in the topographic and vegetation heterogeneity of this ecosystem. Results confirmed the inability of present-day flows to entrain bed sediment. Further, our diagrams showed bed shear stresses to be highly sensitive to emergent vegetation density and water-surface slope but less sensitive to water depth and periphyton or floating vegetation abundance. These findings suggested that instituting a pulsing flow regime could be the most effective means to restore sediment redistribution to the Everglades. However, pulsing flows will not be sufficient to erode sediment from sloughs with abundant spikerush, unless spikerush density first decreases by natural or managed processes. Our methods provide a novel tool for identifying restoration parameters and performance measures in many types of vegetated aquatic environments where sediment erosion and deposition are involved.
KEYWORDS:Wetlands; Everglades; Restoration; Modeling; Bed shear stress; Flow
through vegetation
through emergent vegetation; florida everglades; slough landscape;
national-park; salt-marsh; channel; transport; ridge; macrophytes;
morphology |
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(2009b) Larsen, L.G., Harvey, J.W. and Crimaldi, J.P. Predicting organic floc transport dynamics in shallow aquatic ecosystems: Insights from the field, the laboratory, and numerical modeling. Water Resources Research 45 (W01411, doi:10.1029/2008WR007221), 13 p.. |
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ABSTRACT
Transport of particulate organic material can impact watershed sediment and nutrient budgets and can alter the geomorphologic evolution of shallow aquatic environments. Prediction of organic aggregate ("floc'') transport in these environments requires knowledge of how hydraulics and biota affect the entrainment, settling, and aggregation of particles. This study evaluated the aggregation and field transport dynamics of organic floc from a low-gradient floodplain wetland with flow-parallel ridges and sloughs in the Florida Everglades. Floc dynamics were evaluated in a rotating annular flume and in situ in the field. Under present managed conditions in the Everglades, floc is not entrained by mean flows but is suspended via biological production in the water column and bioturbation. Aggregation was a significant process affecting Everglades floc at high flume flow velocities (7.0 cm s(-1)) and during recovery from high flow; disaggregation was not significant for the tested flows. During moderate flows when floc dynamics are hydrodynamically controlled, it is possible to model floc transport using a single "operative floc diameter'' that accurately predicts fluxes downstream and to the bed. In contrast, during high flows and recovery from high flows, aggregation dynamics should be simulated. When entrained by flow in open-water sloughs, Everglades floc will be transported downstream in multiple deposition and reentrainment events but will undergo net settling when transported onto ridges of emergent vegetation. We hypothesize that net transport of material from open to vegetated areas during high flows is critical for forming and maintaining distinctive topographic patterning in the Everglades and other low-gradient floodplains.
KEYWORDS:fluvial suspended sediment; rotating circular flume; fine-grained
sediments; depositional history; vertical transport; fractal
dimensions; florida everglades; steady-state; marine snow; size |
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(2009) Leeds, J.A., Garrett, P.B. and Newman, J.M. Assessing Impacts of Hydropattern Restoration of an Overdrained Wetland on Soil Nutrients, Vegetation and Fire. Restoration Ecology 17(4), 460-469. |
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ABSTRACT
Restoring hydrology to overdrained wetlands can facilitate restoration of degraded ecosystems. In the northern Everglades, the Rotenberger Wildlife Management Area (RWMA) became a rain-driven system as historic overland inflows were redirected. Consequently, the soil experienced severe drying, resulting in frequent muck fires, oxidation and a shift in vegetation composition. In July 2001, the RWMA hydropattern restoration began utilizing discharge from Stormwater Treatment Area 5 (STA-5), a constructed wetland. As a result, predischarge hydroperiods averaging 124 days increased to an average of 183 days. Soil total phosphorus (TP) concentrations in the topsoil layer did not significantly change from predischarge (637 mg/kg) to postdischarge (633 mg/kg) concentrations. Muck fires appear to be the catalyst for rapid alterations in the bioavailability and solubility of P. Prior to muck fires, soil P pools were 88% organic P and 12% inorganic P, shifting to 49% organic P and 51% inorganic P measured after a muck fire. Sawgrass (Cladium jamaicense, OBL) and Cattail (Typha domingensis, OBL) cover approximately 75% of the RWMA area as dominant or codominant species. Predischarge vegetation community composition documented obligate (OBL) and facultative wetland (FACW) species, each composing 46% of all species surveyed. Postdischarge vegetation compositions shifted to 59% OBL and 39% FACW species. In addition, there were significant elevations in tissue nutrient concentrations, TP, and total nitrogen, between pre- and postdischarge samples. An adaptive management approach to inflow and outflow operations will be an important part of successful wetland restoration.
KEYWORDS:everglades; hydropattern restoration; oxidation; phosphorus; soil;
vegetation composition; wetlands
northern everglades; florida everglades; marsh; phosphorus; cattail;
forms |
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(2009) Li, S.W., Mendelssohn, I.A., Chen, H.J. and Orem, W.H. Does sulphate enrichment promote the expansion of Typha domingensis (cattail) in the Florida Everglades?(1). Freshwater Biology 54(9), 1909-1923. |
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ABSTRACT
The expansion of Typha domingensis into areas once dominated by Cladium jamaicense in the Florida Everglades has been attributed to altered hydrology and phosphorus enrichment, although increased concentrations of sulphate and phosphorus often coincide. The potential importance of hydrogen sulphide produced from sulphate in the expansion of Typha has received little attention. The present study aimed to quantify the comparative growth and photosynthetic responses of Cladium and Typha to sulphate/sulphide. 2. Laboratory experiments showed that Cladium is less tolerant of sulphide than Typha. Cladium was adversely affected at sulphide concentrations of approximately 0.22 mm, while Typha continued to grow well and appeared healthy up to 0.69 mm sulphide. 3. Experiments in field mesocosms provided strong support for species-specific differences in physiology and growth. Regardless of interstitial sulphide concentrations attained, Typha grew faster and had a higher photosynthetic capacity than Cladium. However, sulphide concentrations in the mesocosms reached only 0.18 mm which, based on the hydroponic study, was insufficient to affect the growth or photosynthetic responses of either species. Nevertheless, the upper range of sulphide (0.25-0.375 mm) in Everglades' soil is high enough, based on our results, to impact Cladium but not Typha. 4. This research supports the hypothesis that sulphide accumulation could affect plant species differentially and modify species composition. Consequently, the role of sulphate loading should be considered, in conjunction with hydroperiod, phosphorus availability and disturbances, in developing future management plans for the Everglades
KEYWORDS:Cladium; Everglades; growth; sulphide toxicity; Typha
fresh-water wetlands; cladium-jamaicense; species distribution;
pore-water; sulfide; soil; roots; macrophytes; mechanisms; toxicity |
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(2009) Liu, G.L., Cai, Y., Mao, Y.X., Scheidt, D., Kalla, P., Richards, J., Scinto, L.J., Tachiev, G., Roelant, D. and Appleby, C. Spatial Variability in Mercury Cycling and Relevant Biogeochemical Controls in the Florida Everglades. Environmental Science & Technology 43(12), 4361-4366. |
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ABSTRACT
Spatial patterns in mercury cycling and bioaccumulation at the landscape level in the Everglades were investigated by collecting and analyzing multimedia samples for mercury species and biogeochemical characteristics from 228 randomly located stations. Higher total mercury (THg) in environmental compartments (surface water, soil, flocculent detrital material (floc), and periphyton) generally occurred in the northern and central Everglades, but higher THg in water and periphyton in the Everglades National Park was an exception. Multiple biogeochemical characteristics, such as surface water dissolved organic matter (DOCSW), pH, chloride, and compositional properties of solid compartments (soil and floc), were identified to be important factors controlling THg distribution. Methylmercury (MeHg) was also higher in the northern Everglades for water, soil, and floc, but not for periphyton. Higher mosquitofish THg and bioaccumulation factor were observed in the central and southern Everglades, partially in accordance with periphyton MeHg distribution, but not in the "hot spot" areas of water, soil, or floc MeHg. The discrepancy in mercury bioaccumulation and mercury distribution in environmental compartments suggests that in addition to MeHg production, biogeochemical controls that make MeHg available to aquatic organisms, such as DOCSW and compositional properties of soil and floc, are important in mercury bioaccumulation.
KEYWORDS:dissolved organic-matter; methylmercury concentrations; humic
substances; gaseous mercury; surface waters; food webs; binding;
bioaccumulation; bioavailability; methylation |
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(2009a) Liu, Y. and Labuschagne, M.T. The influence of environment and season on stalk yield in kenaf. Industrial Crops and Products 29(2-3), 377-380. |
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ABSTRACT
Kenaf is an important fiber crop worldwide. it was recently introduced to South Africa as a commercial fiber crop. The aim of this study was to deter-mine how different environments and seasons influence stalk yield. Nine kenaf cultivars from various countries were analysed in two environments, over two consecutive seasons, where one location was irrigated and the other not. Data were recorded for total fresh yield, defoliated stalk yield and dry stalk yield. Yield stability was analysed with four different statistical models. The dry stalk yield varied from 15.33 to 17.78 ton/ha. El Salvador and Tainung 2 had high dry stalk yields in the favourable environments, but Tainung 2 did not have stable yield across all trials. Everglades 41 and El Salvador were the most stable of the varieties across both environments and seasons. El Salvador was the cultivar that had the highest and most stable dry stalk yield in the two seasons and two locations in South Africa, and should perform well in commercial production.
KEYWORDS:South Africa cultivation; Fiber; Kenaf; Stalk yield
statistical-analysis; trials |
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(2009b) Liu, Z.W., Volin, J.C., Owen, V.D., Pearlstine, L.G., Allen, J.R., Mazzotti, F.J. and Higer, A.L. Validation and ecosystem applications of the EDEN water-surface model for the Florida Everglades. Ecohydrology 2(2), 182-194. |
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ABSTRACT
The Everglades Depth Estimation Network (EDEN) is all integrated network of real-time water-level monitoring, ground-elevation modelling, and water-surface modelling that provides scientists and water managers with current (2000-present), on-line water-level and water-depth information for the fresh water Everglades. Continuous daily spatial interpolations of surface water-level gage data from the EDEN water-surface model are presented on grid with 400-m spacing. The direct model output is continuous daily surface-water level, and other hydrologic data such as water depth and hydroperiod call he derived together with ground digital elevation models. This paper validated the spatially continuous EDEN water-surface model for the Everglades. Florida by Using an independent field-measured dataset. Three model applications were also demonstrated: to estimate site-specific,round elevation, to create water-depth time series for tree islands, and to generate contiguous water coverage areas. We found that there were no statistically significant differences between model-predicted and field-observed water-level data in central Everglades (p = 0.51). Over 95% of the predicted-water levels matched observed-water levels within the range of +/-5 cm. Overall, the model is reliable by a root mean square error (RMSE) of 3.3 cm. The accurate. high-resolution hydrological data, generated over broad spatial and temporal scales by the EDEN water-surface model, provides a Previously missing key to understanding the habitat requirements and linkages among native and invasive populations. including fish. wildlife. wading birds, and plants. The EDEN model is a powerful tool that Could he adapted for other ecosystem-scale restoration and management programs worldwide.
KEYWORDS:model validation; water level; water depth; ecosystem application;
Everglades
sable seaside-sparrow; community structure; level fluctuations; prairie
wetlands; wading birds; fish; landscape; restoration; vegetation;
dynamics |
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(2009) Lloyd, J.D., Slater, G.L. and Snow, S. Demography of Reintroduced Eastern Bluebirds and Brown-Headed Nuthatches.
Journal of Wildlife Management 73(6), 955-964. |
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ABSTRACT
Species reintroductions are used commonly as a tool for conservation, but rigorous, quantitative assessments of their outcome rarely occur. Such assessments are critical for determining success of the reintroduction and for identifying management actions needed to ensure persistence of reintroduced populations. We collected 9 years of demographic data on populations of brown-headed nuthatches (Sitta pusilla) and Eastern bluebirds (Sialia sialis) reintroduced via translocation into Long Pine Key, Everglades National Park, Florida, USA. Realized population growth of brown-headed nuthatches was positive in the first 3 years after cessation of translocations (lambda(2002) = 1.15, SE = 0.13; lambda(2003) = 1.28, SE = 0.12; lambda(2005) = 1.32, SE = 0.20) but became negative thereafter (lambda(2006) = 0.67, SE = 0.10; lambda(2007) = 0.77, SE = 0.13). Realized growth rate for the Eastern bluebird population did not vary among years and indicated either a stable or a slowly declining population (lambda = 0.92, SE = 0.04). Reintroductions were a qualified success; they resulted in the re-establishment of populations of both species, but neither population grew to the extent expected and both remained at risk of extinction. (JOURNAL OF WILDLIFE MANAGEMENT 73(6): 955-964; 2009)
KEYWORDS:brown-headed nuthatch; Eastern bluebird; Everglades; population growth;
populations; Pradel model; reintroduction; Sialia sialis; Sitta pusilla
population-growth; recapture; birds; time; mark |
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(2009) Lorenz, J.J., Langan-Mulrooney, B., Frezza, P.E., Harvey, R.G. and Mazzotti, F.J. Roseate spoonbill reproduction as an indicator for restoration of the Everglades and the Everglades estuaries. Ecological Indicators 9(S96-S107 |
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ABSTRACT
Ecological monitoring is key to successful ecosystem restoration. Because all components within an ecosystem cannot be monitored, it is important to select indicators that are representative of the system, integrate system responses, clearly respond to system change, can be effectively and efficiently monitored, and are easily communicated. The roseate spoonbill is one ecological indicator species that meets these criteria within the Everglades ecosystem. Monitoring of roseate spoonbills in Florida Bay over the past 70 years has shown that aspects of this species' reproduction respond to changes in hydrology and corresponding changes in prey abundance and availability. This indicator uses nesting location, nest numbers and nesting success in response to food abundance and availability. In turn, prey abundance is a function of hydrological conditions (especially water depth) and salinity. Metrics and targets for these performance measures were established based on previous findings. Values of each metric were translated into indices and identified as stoplight colors with green indicating that a given target has been met, yellow indicating that conditions are below the target, but within an acceptable range of it, and red indicating the measure is performing poorly in relation to the target.
KEYWORDS: Ecological indicators; Everglades restoration; Roseate spoonbill;
Wading birds; Restoration assessment
florida bay; southern florida; wading birds; fishes; vegetation;
mangroves; abundance; habitat; model |
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2009 (A-L) |
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"Everglades" literature (M-Z) for year 2009 - CONTINUED on a separate page
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