Spatio–Temporal Patterns of Soil Phosphorus Enrichment in Everglades Water Conservation Area 2A

DeBusk, W. F.; Newman, Susan; Reddy, K. R.

doi:10.2134/jeq2001.3041438x

Cited by 101 publications

(91 citation statements)

References 27 publications

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“…In WCA-3 from 1992 to 2003, we estimated that the area with TPm >500 mg kg −1 increased at a rate of approximately 1% year −1 . While this represented a considerably high rate of increase, it was still lower than a rate of 5.25% year −1 calculated for WCA-2A from 1991 to 1998 (DeBusk et al, 2001). Our data indicated that while nutrient loading to WCA-3 has affected a smaller percentage of the area of WCA-3 than WCA-2A, the total area of WCA-3 with TPm > 500 mg kg −1 in both 1992 and 2003 was greater than the total area of WCA-2A with TPm > 500 mg kg −1 in 1998.…”

Section: Geostatistical Analysescontrasting

confidence: 57%

Recent Changes in Soil Total Phosphorus in the Everglades: Water Conservation Area 3

Bruland

Osborne

Reddy

et al. 2006

Environ Monit Assess

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We assessed recent changes in the distribution of soil total phosphorus (TP) in Water Conservation Area 3 (WCA-3) of the Everglades. Soil cores were collected in 1992 and 2003 at 176 sites. To reflect hydrologic boundaries within the system, WCA-3 was divided into three zones (3AN, 3AS, and 3B). Total P was mapped on both a mass (TPm) and a volumetric basis (TPv) to determine if spatial distributions varied depending on the choice of units.Interpolated maps for both years showed that the highest levels of TPm were located in 3AN and in boundary areas of all zones that received surface water inputs of P from canals. Increases in TPm were greatest in central 3AN in an area adjacent to the Miami Canal that received inputs from a water control structure. Interpolated maps for TPv illustrated that a hotspot present in 1992 had disappeared by 2003. The highest levels of TPv in 2003 were located in northwestern 3AN, a region of WCA-3 that has been chronically overdrained and burned in 1999. From 1992 to 2003, increases in TPm were observed for 53% of the area of WCA-3, while only 16% of WCA-3 exhibited increases in TPv. In 1992, approximately 21% of WCA-3 had TPm concentrations in the 0-10 cm layer > 500 mg kg −1 , indicating P enrichment beyond historic levels. Eleven years later, 30% of the area of WCA-3 had TPm > 500 mg kg −1 . This indicated that during this period, the area of WCA-3 with enriched TPm concentrations increased about one % year −1 .

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Section: Geostatistical Analysescontrasting

confidence: 57%

Recent Changes in Soil Total Phosphorus in the Everglades: Water Conservation Area 3

Bruland

Osborne

Reddy

et al. 2006

Environ Monit Assess

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“…P loading from precipitation is difficult to accurately determine but is estimated to be 14.7 Mg P/yr (Davis 1994). Eutrophication has resulted in a large expanse of enriched soil that has significantly influenced the vegetation composition (Davis 1994, DeBusk et al 2001, Sklar et al 2005. This area has also been well studied in terms of ecological structure and function (Appendix).…”

Section: Study Sitementioning

confidence: 99%

Multiple Regime Shifts in a Subtropical Peatland: Community‐specific Thresholds to Eutrophication

Hagerthey

Newman

Rutchey

et al. 2008

Ecological Monographs

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Abstract. Ecosystems have a natural resilience to perturbations, where resilience is the magnitude of a disturbance that an ecosystem can resist before changes in structure, function, and services result in a regime shift. The Everglades region of Florida, USA, has been detrimentally impacted by phosphorus (P) enrichment and a regime shift from Cladium (sawgrass) to Typha (cattail) marsh has been described. We examine another facet of the lownutrient Everglades stability regime, open-water sloughs, to determine if eutrophication leads to similar regime shifts.We analyzed surface water P and soil P as controlling variables that, once a critical threshold is surpassed, alter ecosystem state variables. Nonlinear relationships between P and vegetation were observed along a northern Everglades eutrophication gradient. In addition to the Cladium-Typha regime shift, a second independent regime shift, slough-Typha, was identified. Synoptic surveys of 49 sloughs within the boundary between the slough and Typha regime revealed that surface water total phosphorus (TP) and the benthic algal floc layer (BAFL) were the controlling variables, with critical thresholds of 11 lg/L and 412 mg/kg, respectively. The slough regime below these thresholds was characterized by calcareous periphyton (BAFL TP ¼ 298 mg P/kg; BAFL calcium ¼ 149 g Ca/kg). Above the TP thresholds, vegetation composition shifted to open-marsh species with significantly higher BAFL TP (700 mg P/kg) and total organic carbon (TOC) (350 g C/kg). A second BAFL TP threshold occurred at 712 mg P/kg, above which Nymphaea dominated and BAFL TP (1034 mg P/kg) and TOC (417 g C/kg) significantly increased. Nymphaea sloughs transitioned to the Typha regime. The boundary reflects the loss of ecosystem resilience due to eutrophication. Both low-nutrient stability regimes (slough and Cladium) lie precariously close to the P critical threshold but differ in how eutrophication is absorbed and resisted. The slough regime transitions rapidly through a series of ecosystem state changes linked to positive feedback loops that affect P dynamics, whereas the Cladium regime does not. An adaptive management strategy has been implemented to address the surface water TP threshold; however, to ensure successful restoration of the Everglades, the BAFL and soil TP thresholds also need to be considered.

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“…However, the maximum TP values in the hotspots from 1992 were in the 450 to 550 mg kg 21 range, rather than the 620 to 720 mg kg 21 range reported in this study. Historical background TP concentrations in WCA-2A have been estimated to be less than 500 mg kg 21 (DeBusk et al, 2001). Adopting this estimate for WCA-3, according to our interpolated map, 25% (179 ha) of 3AN currently has elevated TP levels.…”

mentioning

confidence: 95%

Spatial Distribution of Soil Properties in Water Conservation Area 3 of the Everglades

Bruland

Grunwald

Osborne

et al. 2006

Soil Science Soc of Amer J

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The need to integrate environmental responses at the landscape scale is a reoccurring theme in biogeochemistry and ecology. This linkage can be addressed by using geostatistics to examine spatial patterns and then assessing the relationships of these patterns to known ecosystem drivers. In this study, we used a stratified random sampling design to collect soil cores from 388 sites to quantify the spatial distribution of soil properties in a 233 000 ha subtropical wetland, Water Conservation Area 3 (WCA-3). To reflect hydrologic boundaries within the system, WCA-3 was divided into three zones: 3AN, 3AS, and 3B. Interpolated maps indicated that the highest levels of bulk density were located in western 3AN, whereas the highest total phosphorus (TP) values were located in northern 3AN and in areas adjacent to a canal bisecting the area. Twenty-five percent of 3AN had TP concentrations in the 0-to 10-cm layer . 500 mg kg 21 , indicating enrichment beyond historic levels. Only 5% of 3AS and 6% of 3B showed TP . 500 mg kg 21 . Total nitrogen (TN) and carbon (TC) were lowest in western 3AN, whereas the rest of WCA-3 had higher and more homogenous TN and TC distributions. Overall, distributions of soil properties were more homogeneous in 3AS than they were in 3AN or 3B. The approach used in this study provides a model for assessing current impacts to WCA-3, supplies baseline conditions against which future restoration efforts can be evaluated, and could be used in other landscape-scale wetland restoration projects.

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Spatio–Temporal Patterns of Soil Phosphorus Enrichment in Everglades Water Conservation Area 2A

Cited by 101 publications

References 27 publications

Recent Changes in Soil Total Phosphorus in the Everglades: Water Conservation Area 3

Recent Changes in Soil Total Phosphorus in the Everglades: Water Conservation Area 3

Multiple Regime Shifts in a Subtropical Peatland: Community‐specific Thresholds to Eutrophication

Spatial Distribution of Soil Properties in Water Conservation Area 3 of the Everglades

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