Multi-tissue stable isotope analysis and acoustic telemetry reveal seasonal variability in the trophic interactions of juvenile bull sharks in a coastal estuary

摘要: Summary1. Understanding how natural and anthropogenic drivers affect extant food webs is critical topredicting the impacts of climate change habitat alterations on ecosystem dynamics.2. In Florida Everglades, seasonal reductions in freshwater flow precipitation lead toannual migrations aquatic taxa from marsh habitats to deep-water refugia estuaries.The timing intensity reductions, however, will be modified by ongoingecosystem restoration predicted change.3. importance seasonally pulsed resources predators pre-dicting management their populations. As with manylarge predators, it difficult determine what extent like bull sharks(Carcharhinus leucas) coastal Everglades make use prey pulses currently.4. We used passive acoustic telemetry whether shark movements responded tothe pulse prey. To investigate possibility that sharks fed prey, wemodelled dynamics stable isotope values blood plasmaunder different assumptions temporal variability diets physiological dynamicsof tissue turnover isotopic discrimination.5. Bull increased upstream channels during late dry season, andalthough our previous work shows long-term specialization sharks, iso-tope suggested some individuals adjusted take advantage preyentering system marsh, as such this may an important resource for thenursery.6. Restoration efforts are increase hydroperiods water levels, likelyshifting timing, duration pulses, which could have negative conse-quences population and/or induce shifts behaviour.7. factors influencing propensity specialize or adopt more flexibletrophic interactions step fully understanding ecological role ofpredators roles vary environmental changes.Key-words: webs, use, movements, nursery, trophic ecology, d