PS 45-17
Quantifying the movement and habitat use of native sunfishes in response to seasonal hydrological variation in the Everglades
Understanding animal habitat selection and inter-habitat movements plays an important role in population and community ecology. Yet, obtaining a sufficiently high spatiotemporal resolution of the movement paths of organisms remains a major challenge in movement ecology. In this study, we use a combination of tagging and enclosure techniques to gain this high spatiotemporal resolution and examined the movement and habitat use of native centrarchid fishes (warmouth), in relation to seasonal variation in environmental conditions, notably hydrology. We conducted our experiment in an experimental wetland facility at Loxahatchee National Wildlife Refuge in the Everglades. Low frequency Radio Frequency Identification (RFID) technology was used to track the movement and habitat use of fishes individually tagged with 21 mm Passive Integrated Transponder (PIT) tags. To overcome the sparse recapture rate inherent in tagging studies, we use six replicate 12m by 4 m field in situ enclosures, equipped with an antenna array. Each enclosure spans three key Everglades habitat types: ridge, slough and alligator holes, along an increasing water depth gradient.
Results/Conclusions
Antenna detections collected as water levels receded and then re-flooded show variation in the use of the three habitats by warmouth across season and changing hydrology. Overall, warmouth used the deepest alligator hole habitat at decreasing and low water levels with minor slough usage and minimal to no ridge use. This changed abruptly upon the start of the rainy season. As water levels began to increase, habitat usage shifted with a significant increase in ridge use and decrease in alligator hole use. Later when water levels stabilized, ridge use decreased slightly and use of the alligator hole and slough was similarly equal. These data suggest a degree of temporal partitioning in habitat usage that may relate to foraging and predation risk. We also noted significant intra-individual variation in both movement rates and use of microhabitat, which we expect to relate to variation in personality type to quantify in future work.