Habitat conservation

Bonefish Albula vulpes are an economically important sport fish that has historically bolstered the recreational flats fisheries of the Florida Keys and The Bahamas; an industry with an annual economic impact of US$465 million and US$169 million, respectively. Analyses of fishing guide logbooks and guide interviews indicate that the population of bonefish in south Florida has declined. Due to the economic and cultural importance of these fisheries, protection of spawning and nursery habitats is integral to population recovery and stability. However, knowledge gaps persist in how abiotic and biotic habitat factors influence reproduction and recruitment. Without clear delineation of spawning and recruitment habitats, bonefish populations remain vulnerable to anthropogenic disturbances. Bonefish partake in a unique three-point spawning migration, migrating from shallow-water home flats to form nearshore pre-spawning aggregations (PSA) before moving offshore to spawn. Using active acoustic telemetry, sonar imagery, and CTD profiles, the first complete account of offshore spawning movements and novel deep diving behavior was accomplished. Bonefish reached depths of 137.9 m and spawned at 67.3 m, a depth associated with the pycnocline/thermocline. Previous efforts show spatiotemporal plasticity in spawning, a behavior counter to other aggregation forming fishes.

The objective of this research was to study the impacts of large USSE facilities on wildlife movement corridors and habitat connectivity in Florida to identify important habitat patches and movement corridors significant for potential Florida panther (Puma concolor coryi) dispersal, conservation, and recovery. Large carnivores (such as Florida panther) have often been examined as conservation umbrellas for large-scale connectivity planning due to their extensive spatial requirements (Beier et al., 2006, Thorne et al., 2006). In addition, Florida panther is relatively well-studied species that have been listed as endangered under the US Endangered Species Act for over 40 years, due to habitat fragmentation and reduction. Habitat suitability was compared before and after the installation of the USSE facilities using RandomForest model developed by Frakes and Knight (in prep). The connectivity study focused on comparing current density and effective resistance (resistance distance) before and after the installations of USSE facilities and was conducted using Circuitscape 4.0. The impacts on habitat connectivity were the most substantial in the areas where the USSE facilities were installed on or around wildlife corridors, near focal areas, and in large clusters. The study has identified important linkages and new pathways that animals may try to take in order to bypass the facilities. The study has also shown that installation of USSE facilities in areas not suitable as habitat for Florida panthers, but still permeable or semi-permeable (e.g., agricultural lands), can substantially impact connectivity between focal areas.

Oyster reefs support diverse estuarine communities and food webs. Factors controlling oyster reef community development were studied on restored reefs in the St. Lucie Estuary. Freshwater discharges create stresses that cause oyster mortality, habitat loss and reduction in reef community diversity. Using structural equation modeling, it was demonstrated that salinity, turbidity, and chlorophyll-a gradients influence oysters and some reef invertebrate species, but did not support the predictions of the Intermediate Disturbance Hypothesis. In contrast, diversity and species richness were greatest at low stress sites. A field experiment showed that topographic relief and architectural complexity enhanced colonization and growth of reef-building species (e.g.oysters and mussels). The relief by complexity interaction had a higher order, synergistic effect on oyster abundance. When considered separately, increasing relief further enhanced dominant sessile taxa (cirripeds and ascideans) ; while, increasing complexity supported greater species richness and the abundance of cirripeds.