LB 11-141 - CANCELLED - Water-works? Implications of large-scale Everglades restoration for threatened bat species

Background/Question/Methods:

Wetlands provide critical foraging habitat for many species, but over half of wetlands worldwide have been degraded or destroyed. Although wetland restoration efforts have become more common, little is known about the impacts on bats. Understanding the effects of these landscape changes is particularly important for threatened species like the endangered Florida bonneted bat (Eumops floridanus), whose geographic range is covered in wetlands that face increasing threats from development and sea level rise. We investigated the effects on bats of a large-scale hydrologic restoration project expected to affect over 2.5 million acres of wetlands and estuaries in the Florida Everglades. We conducted acoustic surveys at 194 sites in 2020 and 2021 (97 each year) to document foraging and habitat use by E. floridanus and the greater bat community. Detectors recorded at each site for 16 total nights during 4 distinct sampling periods spanning the dry and wet seasons. Sites were randomly stratified across a restoration gradient (unrestored, partially restored, restored) and compared with adjacent reference areas. Hydrologic and vegetation metrics were measured at each site to investigate drivers of bat activity in the context of wetland restoration. Acoustic files were classified and manually vetted in Kaleidoscope Pro.

Results/Conclusions:

We collected over 800,000 bat call files and manually verified over 12,000 E. floridanus call files detected at 189 of 194 sites sampled and 1,301 of 3,239 nights sampled. Using generalized linear mixed models, we describe patterns of general bat activity and likelihood of foraging relative to restoration categories to test the relative importance of habitat characteristics that explain habitat selection. Restoration categories provided mixed results, but the best model for general E. floridanus activity included mean daily water depth, hydroperiod, and vegetation community as important predictor variables. This suggests that activity for this species increases with deeper water, longer periods of inundation, and in freshwater forested wetlands, all characteristics associated with restored hydrology on the landscape. The likelihood of foraging followed similar patterns. Analysis of responses by the greater bat community is ongoing. Based on our results, it appears that the restoration will likely have a positive impact on E. floridanus overall, although further exploration of the mechanisms behind these associations is needed. Insights from this study will inform immediate management decisions for this endangered species, contribute to our understanding of how bats more broadly select for foraging habitat, and inform how species may respond to future restoration efforts.