Brazilian peppertree, Schinus terebinthifolius Raddi (Sapindales: Anacardiaceae), introduced from... more Brazilian peppertree, Schinus terebinthifolius Raddi (Sapindales: Anacardiaceae), introduced from South America, invades a variety of habitats in Florida (e.g. disturbed sites, coastal mangrove forests). The objective of this study was to evaluate the effect of host-plant quality on the performance of Episimus unguiculus Clarke (=E. utilis Zimmerman) (Lepidoptera: Tortricidae), a potential biocontrol agent of Brazilian peppertree. Experiments were conducted in
The purpose of this study was to determine the seasonal water use patterns of dominant macrophyte... more The purpose of this study was to determine the seasonal water use patterns of dominant macrophytes coexisting in the coastal Everglades ecotone. We measured the stable isotope signatures in plant xylem water of Rhizophora mangle, Cladium jamaicense, and Sesuvium portulacastrum during the dry (DS) and wet (WS) seasons in the estuarine ecotone along Taylor River in Everglades National Park, FL, USA. Shallow soilwater and deeper groundwater salinity was also measured to extrapolate the salinity encountered by plants at their rooting zone. Average soil water oxygen isotope ratios (delta(18)O) was enriched (4.8 +/- 0.2 per thousand) in the DS relative to the WS (0.0 +/- 0.1 per thousand), but groundwater delta(18)O remained constant between seasons (DS: 2.2 +/- 0.4 per thousand; WS: 2.1 +/- 0.1 per thousand). There was an inversion in interstitial salinity patterns across the soil profile between seasons. In the DS, shallow water was euhaline [i.e., 43 practical salinity units (PSU)] while groundwater was less saline (18 PSU). In the WS, however, shallow water was fresh (i.e., 0 PSU) but groundwater remained brackish (14 PSU). All plants utilized 100% (shallow) freshwater during the WS, but in the DS R. mangle switched to a soil-groundwater mix (delta 55% groundwater) while C. jamaicense and S. portulacastrum continued to use euhaline shallow water. In the DS, based on delta(18)O data, the roots of R. mangle roots were exposed to salinities of 25.4 +/- 1.4 PSU, less saline than either C. jamaicense (39.1 +/- 2.2 PSU) or S. portulacastrum (38.6 +/- 2.5 PSU). Although the salinity tolerance of C. jamaicense is not known, it is unlikely that long-term exposure to high salinity is conducive to the persistence of this freshwater marsh sedge. This study increases our ecological understanding of how water uptake patterns of individual plants can contribute to ecosystem levels changes, not only in the southeast saline Everglades, but also in estuaries in general in response to global sea level rise and human-induced changes in freshwater flows.
Thesis (Ph. D.)--University of Miami, 2001. Includes bibliographical references (leaves 176-194).... more Thesis (Ph. D.)--University of Miami, 2001. Includes bibliographical references (leaves 176-194). Photocopy of typescript.
Differential distribution of nutrients within an ecosystem can offer insight of ecological and ph... more Differential distribution of nutrients within an ecosystem can offer insight of ecological and physical processes that are otherwise unclear. This study was conducted to determine if enrichment of phosphorus (P) in tree island soils of the Florida Everglades can be explained by bird guano deposition. Concentrations of total carbon, nitrogen (N), and P, and N stable isotope ratio (δ(15)N) were determined on soil samples from 46 tree islands. Total elemental concentrations and δ(15)N were determined on wading bird guano. Sequential chemical extraction of P pools was also performed on guano. Guano contained between 53.1 and 123.7g-Nkg(-1) and 20.7 and 56.7g-Pkg(-1). Most of the P present in guano was extractable by HCl, which ranged from 82 to 97% of the total P. Total P of tree islands classified as having low or high P soils averaged 0.71 and 40.6gkg(-1), respectively. Tree island soil with high total P concentration was found to have a similar δ(15)N signature and total P concentrat...
The tree islands of the Everglades are considered to be biodiversity “hotspots”, where the majori... more The tree islands of the Everglades are considered to be biodiversity “hotspots”, where the majority of terrestrial species of the Everglades are found. Drainage for agricultural and urban development in the early 1900s has had a severe impact, converting many of them into “ghost tree islands” which have lost most of their woody vegetation and much of their altitude (elevation). A survey conducted in 1973 on one of the prominent ghost tree islands, named “Dineen Island”, provides insights into the past. We compared the results of the 1973 survey with those of a survey conducted in 2009, in order to examine changes in Dineen Island that had taken place over 36 years and to provide information about general trends in the Everglades. Peat loss at Dineen Island was roughly 4 mm yr-1. This subsidence, as a consequence of peat loss, has been accompanied by losses in nitrogen and phosphorus of 234 and 2.5 metric tons (4.5 and 0.05 metric tons per hectare), respectively. As many of the Everg...
Climate change due to elevated carbon dioxide levels in the atmosphere presents a long-term threa... more Climate change due to elevated carbon dioxide levels in the atmosphere presents a long-term threat to the biosphere. The contribution of soil oxidation to global carbon dioxide levels is of growing concern. For over five millennia, the Everglades has been accreting peat soils and acting as a carbon sink. Anthropogenic drainage of the Everglades, one of the largest deposits of organic soils in North America, began in the 1880s. Subsequently, the peat soils began subsiding and releasing carbon dioxide (C02) into the atmosphere. We quantified subsidence and C02 evolution at the regional scale by calculating the changes in peat volume using surface maps reconstructed from historical and current data. We determined the amount of peat that has been lost during the ensuing century, to evaluate the impact of drainage for agricultural development and urbanization on the Everglades. To do this, we used spatially referenced peat surface data, historical survey data and recent information gathe...
The purpose of this study was to determine the seasonal water use patterns of dominant macrophyte... more The purpose of this study was to determine the seasonal water use patterns of dominant macrophytes coexisting in the coastal Everglades ecotone. We measured the stable isotope signatures in plant xylem water of Rhizophora mangle, Cladium jamaicense, and Sesuvium portulacastrum during the dry (DS) and wet (WS) seasons in the estuarine ecotone along Taylor River in Everglades National Park, FL, USA. Shallow soilwater and deeper groundwater salinity was also measured to extrapolate the salinity encountered by plants at their rooting zone. Average soil water oxygen isotope ratios (delta(18)O) was enriched (4.8 +/- 0.2 per thousand) in the DS relative to the WS (0.0 +/- 0.1 per thousand), but groundwater delta(18)O remained constant between seasons (DS: 2.2 +/- 0.4 per thousand; WS: 2.1 +/- 0.1 per thousand). There was an inversion in interstitial salinity patterns across the soil profile between seasons. In the DS, shallow water was euhaline [i.e., 43 practical salinity units (PSU)] while groundwater was less saline (18 PSU). In the WS, however, shallow water was fresh (i.e., 0 PSU) but groundwater remained brackish (14 PSU). All plants utilized 100% (shallow) freshwater during the WS, but in the DS R. mangle switched to a soil-groundwater mix (delta 55% groundwater) while C. jamaicense and S. portulacastrum continued to use euhaline shallow water. In the DS, based on delta(18)O data, the roots of R. mangle roots were exposed to salinities of 25.4 +/- 1.4 PSU, less saline than either C. jamaicense (39.1 +/- 2.2 PSU) or S. portulacastrum (38.6 +/- 2.5 PSU). Although the salinity tolerance of C. jamaicense is not known, it is unlikely that long-term exposure to high salinity is conducive to the persistence of this freshwater marsh sedge. This study increases our ecological understanding of how water uptake patterns of individual plants can contribute to ecosystem levels changes, not only in the southeast saline Everglades, but also in estuaries in general in response to global sea level rise and human-induced changes in freshwater flows.
Tree islands are habitat for wading birds and a characteristic landscape feature in the Everglade... more Tree islands are habitat for wading birds and a characteristic landscape feature in the Everglades. A total of 93 surface soil and 3 soil core samples were collected from 7 degraded/ghost and 34 live tree islands. The mean Hg concentration in surface soils of ghost tree islands was low and similar to marsh soil. For live tree islands, Hg concentrations in the surface head region were considerably greater than those in mid and tail region, and marsh soils. Hg concentrations in bird guano (286 μg kg(-1)) were significantly higher than those in mammal droppings (105 μg kg(-1)) and plant leaves (53 μg kg(-1)). In addition, Hg concentrations and δ(15)N values displayed positive correlation in soils influenced by guano. During 1998-2010, estimated annual Hg deposition by guano was 148 μg m(-2) yr(-1) and ~8 times the atmospheric deposition.
Brazilian peppertree, Schinus terebinthifolius Raddi (Sapindales: Anacardiaceae), introduced from... more Brazilian peppertree, Schinus terebinthifolius Raddi (Sapindales: Anacardiaceae), introduced from South America, invades a variety of habitats in Florida (e.g. disturbed sites, coastal mangrove forests). The objective of this study was to evaluate the effect of host-plant quality on the performance of Episimus unguiculus Clarke (=E. utilis Zimmerman) (Lepidoptera: Tortricidae), a potential biocontrol agent of Brazilian peppertree. Experiments were conducted in
The purpose of this study was to determine the seasonal water use patterns of dominant macrophyte... more The purpose of this study was to determine the seasonal water use patterns of dominant macrophytes coexisting in the coastal Everglades ecotone. We measured the stable isotope signatures in plant xylem water of Rhizophora mangle, Cladium jamaicense, and Sesuvium portulacastrum during the dry (DS) and wet (WS) seasons in the estuarine ecotone along Taylor River in Everglades National Park, FL, USA. Shallow soilwater and deeper groundwater salinity was also measured to extrapolate the salinity encountered by plants at their rooting zone. Average soil water oxygen isotope ratios (delta(18)O) was enriched (4.8 +/- 0.2 per thousand) in the DS relative to the WS (0.0 +/- 0.1 per thousand), but groundwater delta(18)O remained constant between seasons (DS: 2.2 +/- 0.4 per thousand; WS: 2.1 +/- 0.1 per thousand). There was an inversion in interstitial salinity patterns across the soil profile between seasons. In the DS, shallow water was euhaline [i.e., 43 practical salinity units (PSU)] while groundwater was less saline (18 PSU). In the WS, however, shallow water was fresh (i.e., 0 PSU) but groundwater remained brackish (14 PSU). All plants utilized 100% (shallow) freshwater during the WS, but in the DS R. mangle switched to a soil-groundwater mix (delta 55% groundwater) while C. jamaicense and S. portulacastrum continued to use euhaline shallow water. In the DS, based on delta(18)O data, the roots of R. mangle roots were exposed to salinities of 25.4 +/- 1.4 PSU, less saline than either C. jamaicense (39.1 +/- 2.2 PSU) or S. portulacastrum (38.6 +/- 2.5 PSU). Although the salinity tolerance of C. jamaicense is not known, it is unlikely that long-term exposure to high salinity is conducive to the persistence of this freshwater marsh sedge. This study increases our ecological understanding of how water uptake patterns of individual plants can contribute to ecosystem levels changes, not only in the southeast saline Everglades, but also in estuaries in general in response to global sea level rise and human-induced changes in freshwater flows.
Thesis (Ph. D.)--University of Miami, 2001. Includes bibliographical references (leaves 176-194).... more Thesis (Ph. D.)--University of Miami, 2001. Includes bibliographical references (leaves 176-194). Photocopy of typescript.
Differential distribution of nutrients within an ecosystem can offer insight of ecological and ph... more Differential distribution of nutrients within an ecosystem can offer insight of ecological and physical processes that are otherwise unclear. This study was conducted to determine if enrichment of phosphorus (P) in tree island soils of the Florida Everglades can be explained by bird guano deposition. Concentrations of total carbon, nitrogen (N), and P, and N stable isotope ratio (δ(15)N) were determined on soil samples from 46 tree islands. Total elemental concentrations and δ(15)N were determined on wading bird guano. Sequential chemical extraction of P pools was also performed on guano. Guano contained between 53.1 and 123.7g-Nkg(-1) and 20.7 and 56.7g-Pkg(-1). Most of the P present in guano was extractable by HCl, which ranged from 82 to 97% of the total P. Total P of tree islands classified as having low or high P soils averaged 0.71 and 40.6gkg(-1), respectively. Tree island soil with high total P concentration was found to have a similar δ(15)N signature and total P concentrat...
The tree islands of the Everglades are considered to be biodiversity “hotspots”, where the majori... more The tree islands of the Everglades are considered to be biodiversity “hotspots”, where the majority of terrestrial species of the Everglades are found. Drainage for agricultural and urban development in the early 1900s has had a severe impact, converting many of them into “ghost tree islands” which have lost most of their woody vegetation and much of their altitude (elevation). A survey conducted in 1973 on one of the prominent ghost tree islands, named “Dineen Island”, provides insights into the past. We compared the results of the 1973 survey with those of a survey conducted in 2009, in order to examine changes in Dineen Island that had taken place over 36 years and to provide information about general trends in the Everglades. Peat loss at Dineen Island was roughly 4 mm yr-1. This subsidence, as a consequence of peat loss, has been accompanied by losses in nitrogen and phosphorus of 234 and 2.5 metric tons (4.5 and 0.05 metric tons per hectare), respectively. As many of the Everg...
Climate change due to elevated carbon dioxide levels in the atmosphere presents a long-term threa... more Climate change due to elevated carbon dioxide levels in the atmosphere presents a long-term threat to the biosphere. The contribution of soil oxidation to global carbon dioxide levels is of growing concern. For over five millennia, the Everglades has been accreting peat soils and acting as a carbon sink. Anthropogenic drainage of the Everglades, one of the largest deposits of organic soils in North America, began in the 1880s. Subsequently, the peat soils began subsiding and releasing carbon dioxide (C02) into the atmosphere. We quantified subsidence and C02 evolution at the regional scale by calculating the changes in peat volume using surface maps reconstructed from historical and current data. We determined the amount of peat that has been lost during the ensuing century, to evaluate the impact of drainage for agricultural development and urbanization on the Everglades. To do this, we used spatially referenced peat surface data, historical survey data and recent information gathe...
The purpose of this study was to determine the seasonal water use patterns of dominant macrophyte... more The purpose of this study was to determine the seasonal water use patterns of dominant macrophytes coexisting in the coastal Everglades ecotone. We measured the stable isotope signatures in plant xylem water of Rhizophora mangle, Cladium jamaicense, and Sesuvium portulacastrum during the dry (DS) and wet (WS) seasons in the estuarine ecotone along Taylor River in Everglades National Park, FL, USA. Shallow soilwater and deeper groundwater salinity was also measured to extrapolate the salinity encountered by plants at their rooting zone. Average soil water oxygen isotope ratios (delta(18)O) was enriched (4.8 +/- 0.2 per thousand) in the DS relative to the WS (0.0 +/- 0.1 per thousand), but groundwater delta(18)O remained constant between seasons (DS: 2.2 +/- 0.4 per thousand; WS: 2.1 +/- 0.1 per thousand). There was an inversion in interstitial salinity patterns across the soil profile between seasons. In the DS, shallow water was euhaline [i.e., 43 practical salinity units (PSU)] while groundwater was less saline (18 PSU). In the WS, however, shallow water was fresh (i.e., 0 PSU) but groundwater remained brackish (14 PSU). All plants utilized 100% (shallow) freshwater during the WS, but in the DS R. mangle switched to a soil-groundwater mix (delta 55% groundwater) while C. jamaicense and S. portulacastrum continued to use euhaline shallow water. In the DS, based on delta(18)O data, the roots of R. mangle roots were exposed to salinities of 25.4 +/- 1.4 PSU, less saline than either C. jamaicense (39.1 +/- 2.2 PSU) or S. portulacastrum (38.6 +/- 2.5 PSU). Although the salinity tolerance of C. jamaicense is not known, it is unlikely that long-term exposure to high salinity is conducive to the persistence of this freshwater marsh sedge. This study increases our ecological understanding of how water uptake patterns of individual plants can contribute to ecosystem levels changes, not only in the southeast saline Everglades, but also in estuaries in general in response to global sea level rise and human-induced changes in freshwater flows.
Tree islands are habitat for wading birds and a characteristic landscape feature in the Everglade... more Tree islands are habitat for wading birds and a characteristic landscape feature in the Everglades. A total of 93 surface soil and 3 soil core samples were collected from 7 degraded/ghost and 34 live tree islands. The mean Hg concentration in surface soils of ghost tree islands was low and similar to marsh soil. For live tree islands, Hg concentrations in the surface head region were considerably greater than those in mid and tail region, and marsh soils. Hg concentrations in bird guano (286 μg kg(-1)) were significantly higher than those in mammal droppings (105 μg kg(-1)) and plant leaves (53 μg kg(-1)). In addition, Hg concentrations and δ(15)N values displayed positive correlation in soils influenced by guano. During 1998-2010, estimated annual Hg deposition by guano was 148 μg m(-2) yr(-1) and ~8 times the atmospheric deposition.
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