The role of seasonal wetlands in the ecology of the American alligator

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Title: The role of seasonal wetlands in the ecology of the American alligator
Author: Subalusky, Amanda Lee
Abstract: The American alligator (Alligator mississippiensis ) has been frequently studied in large reservoirs and coastal marshes . Large ontogenetic shifts in their diet and morphology have been linked with changes in habitat use , with adult males using deep , open water and juveniles and nesting females relying on vegetated marsh . In certain regions of the inland portion of the alligator ?s range , these different aquatic habitats are represented by seasonal wetlands and riverine systems that are separated by a terrestrial matrix . Ontogenetic habitat shifts , therefore , would require overland movements between systems , which has important implications for conservation of the species . I tested several commonly used methods of surveying alligator populations to determine the most effective method of studying alligators in seasonal wetlands . I then used systematic trapping , nest surveys and radio telemetry to determine habitat use and overland movement rates by different sex and size classes . I found that seasonal wetlands provided nesting and nursery sites for these inland alligator populations , but that both juveniles undergoing an ontogenetic shift and nesting females move between the wetlands and riverine systems . Overland movements by alligators between the wetland and riverine habitats establish a level of functional connectivity between these aquatic ecosystems . I constructed a habitat suitability index of both the wetlands and the surrounding landscape to determine which patch and landscape characteristics were important to wetland use by alligators . I found that both descriptive wetland characteristics and the spatial relationships between wetlands were important predictors of alligator use . Overland movement was related to upland landuse as well as distance between aquatic habitats . Conserving a variety of wetland sizes and types within an intact upland matrix is critical to maintaining connectivity across the landscape . Furthermore , understanding how species may act as mobile links between ecosystems , particularly those with ontogenetic niche shifts , illustrates the importance of approaching conservation from a landscape perspective .
URI: http : / /hdl .handle .net /1969 .1 /ETD -TAMU -1640
Date: 2009-05-15

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The role of seasonal wetlands in the ecology of the American alligator. Available electronically from http : / /hdl .handle .net /1969 .1 /ETD -TAMU -1640 .

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