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ABSTRACTS |
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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:
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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. |
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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. |
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(2009) 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. |
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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. |
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(2009) Miao, S.L. and Zou, C.B.
Seasonal variation in seed bank composition and its interaction with
nutrient enrichment in the Everglades wetlands. Aquatic
Botany 90(2), 157-164. |
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Abstract
In the Florida Everglades, nutrient enrichment from
agricultural outflow and the change in hydrology have collectively
contributed to the expansion of cattails (Typha spp.). To assess the
effectiveness of prescribed fire in controlling cattails and to
predict vegetation dynamics after the fire, it is important to
understand the seasonal variation of the soil seed bank and how the
seed bank is affected by nutrient enrichment and fire. This paper
investigates the effects of season, nutrient enrichment, and fire on
soil seed bank species composition, richness, and density along a
nutrient gradient in Water Conservation Area 2A (WCA 2A) of the
Florida Everglades. Species richness was significantly affected by
nutrient enrichment and season but not their interaction. Total seed
density, however, was significantly affected by the interaction
between nutrient enrichment and season. Yet, at species level, the
relationship between seed density, nutrient enrichment and season
varied. The highest seed density of cattail occurred in summer at
highly enriched sites, but that of sawgrass occurred in fall
regardless of enrichment; the seed density of water lily was very
low regardless of season and nutrient enrichment, and the highest
Amarathus seed density occurred at highly enriched sites year round.
Moreover, germination timing differed greatly among species. While
cattail seeds had a short incubation period and started to germinate
2-3 days after initiation of the germination assay, sawgrass seeds
generally started to germinate 4 weeks later. Further, both the
prescribed summer fire at the highly enriched site and the natural
winter fire at the moderately enriched site reduced the seed density
of cattail but not of sawgrass. Our results suggest that fire
application for vegetation recovery in WCA 2A would benefit from
explicitly considering seasonal dynamics of the seed bank.
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(2009) Ozturk, Z., Katsenovich,
Y., Tansel, B., Laha, S., Moos, L. and Allen, M. Enhancement of TCE
Attenuation in Soils by Natural Amendments. Soil & Sediment
Contamination 18(1), 1-13. |
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Abstract
The objective of this study was to identify low-cost
natural amendments that could be used as carbon sources and sustain
a bioactive zone to promote biodegradation of TCE in contaminated
shallow groundwater. The natural amendments were compared based on
their geophysical characteristics as well as TCE adsorption
capacities. The amendments studied included low-cost natural and
agricultural materials such as eucalyptus tree mulch, pine bark
mulch, muck from the Florida Everglades, SRS wetland peat,
commercial compost, and peat humus. These natural substrates have
relatively high organic fractions that can retard the movement of
TCE while serving as carbon sources. Batch sorption studies were
conducted to determine the sorption and retardation characteristics
of the amendments for TCE. The experimental results were analyzed in
relation to the geophysical characteristics of the amendments and
compared with those of natural soils. |
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(2009) Wright, A.L. Soil
phosphorus stocks and distribution in chemical fractions for
long-term sugarcane, pasture, turfgrass, and forest systems in
Florida. Nutrient Cycling in Agroecosystems 83(3),
223-231. |
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Abstract
Phosphorus distribution and stability in soils of the
Everglades Agricultural Area (EAA) of south Florida is important
because of changing land uses. We investigated the effects of land
use on P distribution in the soil profile and between chemical
fractions for a histosol of the Florida Everglades. Labile, Fe-Al
bound, Ca-bound, humic-fulvic acid, and residual P pools in 0-15,
15-30, and 30-45 cm depths were determined for drained soils planted
to sugarcane (Saccharum sp.) for 50 yr, pasture for 100 yr,
turfgrass for 60 yr, and forest for 20 yr. The P concentrations of
all chemical fractions decreased with depth in the profile,
indicating accumulation in surface soil resulting from oxidation and
fertilization. Trends in P distribution between chemical fractions
were similar between land uses. Labile P comprised less than 1% of
total P. Fe-Al bound P averaged 2.9% of the total P for turfgrass
and forest, but 11.4 and 9.6% for sugarcane and pasture. Increasing
soil disturbance and long-term fertilization increased P allocation
to inorganic fractions, as Ca-bound P contained 49% of total P for
sugarcane but 28% for other land uses. Total P stocks in the soil
profile (0-45 cm) averaged 1,323, 2,005, 2,294, and 2,317 kg P
ha(-1) for pasture, sugarcane, turfgrass, and forest, respectively.
Under current land uses P in organic fractions represents an
unstable pool since the soil is prone to oxidation under drained
conditions. In contrast, P sequestered in inorganic fractions is
more stable under current land uses, thus sugarcane cultivation and
incorporation of bedrock CaCO3 into surface soil by tillage will
enhance long-term P sequestration. |
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(2009) Wright, A.L. and Inglett,
P.W. Soil Organic Carbon and Nitrogen and Distribution of Carbon-13
and Nitrogen-15 in Aggregates of Everglades Histosols. Soil
Science Society of America Journal 73(2), 427-433. |
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Abstract
Oxidation of Histosols in the Everglades Agricultural
Area (EAA) of South Florida leads to decreases in soil depth,
changes in biogeochemical properties, and may limit land use Options
in the future. The objectives of this study were to determine how
long-term cultivation influences organic matter dynamics and C and N
distribution throughout the profile Of a drained Histosol. We
measured organic C and N stocks, aggregation, and the natural
abundance of delta C-13 and delta N-15 in aggregates from Histosols
100 yr after drainage for two land uses: sugarcane (Saccharum
officinarum L.) and prairie. Macroaggregates comprised the bulk of
total soil for both land uses, averaging 81% of the total soil in
fractions > 0.25 mm. Macroaggregation increased with depth and
the proportion to whole soil was 65% higher at 30 to 45 cm than 0 to
15 cm. Cultivated soil averaged 13% higher organic C, but 11 lower
organic N than prairie throughout the profile (0-45 cm). The
majority of the organic C (76%) and N stocks (77%) was in
macroaggregare fractions > 0.25 mm. The distribution of organic
matter among aggregate-size fractions generally did not differ
between land uses, except that organic C and N were 39 and 44%,
respectively, greater For macroaggregares in prairie than cultivated
soil at 0 to 15 cm. The delta N-15 decreased with depth for both
land uses, indicating that organic matter was more decomposed and
humified in surface soil (0-15 cm). The decrease with depth likely
resulted from inundation of subsurface soils and low O-2 levels,
which subsequently lowered rates of decomposition. The delta C-13
decreased with depth for Cultivated soil but increased for prairie,
and was significantly higher for soil cropped to sugarcane (-25.37
parts per thousand) than prairie (-26.20 parts per thousand). Soil
organic matter under Cultivation was less humified than prairie soil
due to recent C inputs from Sugarcane. The 2-mm fraction had 12%
lower delta N-15 than other fractions, indicating that recent
organic matter inputs accumulated in macroaggregate fractions.
Smaller aggregates contained higher delta N-15 and older organic
matter. In contrast to most studies of mineral soils, Cultivation of
Histosols increased C storage relative to prairie, with the major
difference between land use being higher soil organic matter levels
in the Subsurface (15-45 cm). Thus, cropping may reduce the rate of
oxidation of Histosols ill Southern Florida relative to the prairie
ecosystem. |
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(2008) Carriger, J.F. and Rand, G.M.
Aquatic risk assessment of pesticides in surface waters in and
adjacent to the Everglades and Biscayne National Parks: I. Hazard
assessment and problem formulation. Ecotoxicology 17(7),
660-679. |
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