Data from: Size, sex, and individual-level behavior drive intra-population variation in cross-ecosystem foraging of a top-predator
Data files
Oct 07, 2015 version files 16.58 MB
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Alligator_Capture_Isotope_Data.xlsx
29.61 KB
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Alligator_GPS_Capure_Location_Data.xlsx
16.69 KB
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Alligator_Stomach_Content_Data.xlsx
46.39 KB
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Alligator_Survey_Data.xlsx
9.60 KB
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Prey_Habitat_Isotope_Collection_Site_Data.xlsx
9.24 KB
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Prey_Isotope_Data.xlsx
20.12 KB
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Primary_Producer_Isotope_Data.xlsx
11.30 KB
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Salinity_Data.csv
6.85 KB
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SIAR_Posterior_Adult_Data.csv
3.05 MB
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SIAR_posterior_Large_Juvenile_data.csv
4.44 MB
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SIAR_posterior_Small_Juvenile_Data.csv
4.48 MB
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SIAR_posterior_Sub_Adult_Data.csv
4.43 MB
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SIAR_Simple_Mean_Source_Data.xlsx
8.93 KB
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SIAR_Weighted_Source_Mean_Data.xlsx
9.74 KB
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Trophic_Enrichment_Factors_TEFs.xlsx
8.87 KB
Abstract
1. Large-bodied, top-predators are often highly mobile, with the potential to provide important linkages between spatially distinct food webs. What biological factors contribute to variation in cross-ecosystem movements, however, have rarely been examined. 2. Here, we investigated how ontogeny (body size), sex, and individual-level behavior impacts intra-population variation in cross-ecosystem foraging (i.e., between freshwater and marine systems), by the top-predator Alligator mississippiensis. 3. Field surveys revealed A. mississippiensis uses marine ecosystems regularly and are abundant in estuarine tidal creeks (from 0.3–6.3 individuals/km of creek, n = 45 surveys). Alligator mississippiensis captured in marine/estuarine habitats were significantly larger than individuals captured in freshwater and intermediate habitats. 4. Stomach content analysis showed that small juveniles consumed marine/estuarine prey less frequently (6.7% of individuals) than did large juveniles (57.8%), sub-adult (73%), and adult (78%) size classes. Isotopic mixing model analysis (SIAR) also suggests substantial variation in use of marine/estuarine prey resources with differences among and within size classes between sexes and individuals (range of median estimates for marine/estuarine diet contribution = 0.05–0.76). 5. These results demonstrate the importance of intra-population characteristics (body size, sex, and individual specialization) as key determinants of the strength of predator-driven ecosystem connectivity resulting from cross-ecosystem foraging behaviors. Understanding the factors which contribute to variation in cross-ecosystem foraging behaviors will improve our predictive understanding of the effects of top-predators on community structure and ecosystem function.