RESPONSES OF WOOD STORKS TO HUMAN-INDUCED LANDSCAPE CHANGE IN SOUTH FLORIDA

There is a strong conservation need to understand traits of native species that adapt to urban environments, but results have been equivocal. Wetland birds have shown a strong phylogenetic signal towards urban tolerance; however, these species have largely been ignored in urban studies. I used Wood Storks (Mycteria americana) to determine how a wetland species of conservation concern responded to human-induced landscape change in South Florida. Specifically, my study investigated 1) resource selection of storks in roadway corridors, 2) factors influencing stork prey biomass in roadside created wetlands, 3) dietary flexibility of storks in response to human-induced landscape change, and 4) the impact of urban food subsidies on natural food limitations and stork productivity. I found that storks preferred canals and roadway corridors within the urban landscape. At a finer scale, storks selected for more natural wetland vegetation even within the urban landscape cover type. These results suggest that roadway corridors even within a highly urbanized area may provide adequate foraging habitat for storks. Factors influencing stork prey biomass in roadside created wetlands varied depending on created wetland type. I found that landscape-level vegetation and the physical properties of a created wetland were more influential in permanently inundated created wetlands whereas local-scale vegetation and hydrologic conditions were most influential in ephemeral created wetlands. Storks also selected prey that were more similar to the larger-bodied fishes in created wetlands than the smaller fishes in natural wetlands. Urban nesting storks selected prey that were more characteristic of created wetlands whereas storks nesting in natural wetlands selected prey that was more characteristic of prey found in natural wetlands. These results suggested that storks may have behavioral plasticity in foraging habitat and prey selection to adapt to some degree of human-induced rapid environmental change. Additionally, storks nesting in both urban and natural wetlands had narrow diet breadths and high productivity during optimal natural wetland conditions; however, during suboptimal natural conditions, urban stork diet expanded to include anthropogenic items, leading to increased productivity. Overall, this research provides a mechanistic understanding of how a wetland species persists, and even thrives, in an urban environment.