Drivers of species dispersal between donor and recipient habitats of Common snook in the Florida Coastal Everglades

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Consumer mediated habitat linkages, defined as the transport of biomass to spatially distinct food webs through movements of heterotrophic species, can govern processes at every ecological scale, substantially contributing to the stability, resistance capacity and resiliency of many natural systems.  Species dispersal is one such way these cross habitat linkages are created. Thus, drivers that influence the dynamics of dispersal will likely affect the strength of cross system habitat linkages. Two such drivers that could affect dispersal, are differences in predation risk and productivity between the donor and the recipient habitat. Such that if predation risk is high in the recipient habitat and low in the donor habitat, individual may wait until they are at larger size, when predation risk is lessened to disperse. Conversely, if food availability is more abundant in the donor habitat than in the recipient habitat, dispersal may occur at smaller size.  In the Florida Coastal Everglades estuary, both productivity and predator abundances are low in the freshwater environment, conversely in the marine environment, predation risk and productivity are exponentially higher. This gradient of productivity and predation risk provide an ideal model system to test the strength of predation risk and productivity as a driver that influences dispersal. In this study, we measured dispersal of individual large bodied euryhaline piscivores, common snook (Centropomus undecimalis), from the freshwater environment to the marine environment. We hypothesize that if predation risk in the marine environment is an important driver of dispersal then the likelihood that snook will migrate to the marine environment will be greater at larger sizes. Conversely, if food availability is the dominant driver of dispersal, then migrations to the marine environment will occur at smaller sizes.  In the future, both predation regimes and ecosystem productivities will likely change. Results from this study will help us predict future changes in consumer habitat linkages.