Proximity and local ecological conditions affect odonate assemblages in Ocala National Forest ponds

Odonates (damselflies and dragonflies) are constrained by their requirement for freshwater for reproduction, though adult stages may disperse over dry land. In this study, we tested whether odonate assemblages were more similar in closely located ponds than in more distant ponds, and whether ecological variables predicted pond assemblage structure. To evaluate this question, we collected odonates in both the adult and nymph stages at 16 ponds clustered in four groups in Ocala National Forest in the summer of 2021 and 2023. We collected adults with aerial nets and nymphs with dipnets. We also measured physical and biological characteristics of the ponds, including the presence of potential predators (fish, tadpoles, crayfish). The number of individuals collected varied widely with pond size, but species richness and diversity varied little between groups. Odonate assemblages were slightly more similar if they were within the same group, although this pattern was stronger for dragonflies than for damselflies. With respect to the ecological characteristics of the ponds, adult odonate species richness was related to the area of open water present at a pond. For the nymphs, damselfly abundance, species richness and diversity were related to pond depth, coverage with lilies and small fish presence, whereas dragonfly abundance, species richness and diversity were related to pond size, coverage with grasses and the presence of sunfish. These results suggest that both dispersal and the physical and biological conditions of the habitat determine odonate structure in Ocala ponds. Given the pressure on ecosystems due to development and the limited research on odonates in Florida, we hope that these results will contribute to the support of odonate diversity in Florida.