DOI: 10.5061/dryad.j7049
title: Data from: Size, sex, and individual-level behavior drive intra-population variation in cross-ecosystem foraging of a top-predator

description: 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.
description: Alligator_Capture_Isotope_DataCapture information, biological data, and isotopic data from individual Alligator mississippiensis captured during this study.Alligator_GPS_Capure_Location_DataLatitude and Longitude of capture locations for A. mississippiensisAlligator_Stomach_Content_DataA. mississippiensis stomach content data.Alligator_Survey_DataNightlight count survey dataPrey_Habitat_Isotope_Collection_Site_DataLatitude and longitude of collecting sites for stable isotope samples of primary producers and prey species.Prey_Isotope_DataStable isotope values determined for prey species.Primary_Producer_Isotope_DataStable isotope values determined for primary producer species.Salinity_DataWater salinity during time of this study.SIAR_Posterior_Adult_DataSIAR posterior distributions for adult alligators.SIAR_posterior_Sub_Adult_DataSIAR posterior distributions for sub-adult alligators.SIAR_posterior_Large_Juvenile_dataSIAR posterior distributions for large juvenile alligators.SIAR_posterior_Small_Juvenile_DataSIAR posterior distributions for small juvenile alligatorsSIAR_Simple_Mean_Source_DataIsotope values determined for SIAR sources calculated using simple mean across all prey species.SIAR_Weighted_Source_Mean_DataIsotope values for SIAR sources calculated using a weighted mean by recovered mass of prey.Trophic_Enrichment_Factors_TEFsTrophic enrichment factors used in SIAR analyses