RENR 580
Exploring reef fish distributions
in the Florida Keys Reef Tract to inform site selection for coral reef restoration.
Project Summary
The Florida Keys Reef Tract is experiencing severe habitat loss and degredation due primarily to human activities. Reef fishes play a variety of important roles in mediating the health and prosperity of these vital ecosystems, such as depositing key nutrients and grazing on harmful macroalgae. Understanding what factors influence the distribution of reef fish species could help inform site selection for restoration efforts, as harnessing these beneficial interactions between corals and fishes could increase restoration success.
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Fish occurrence records and habitat data, collected during underwater diver-based surveys, were compiled with environmental data for the Florida Keys region. Possible relationships between species occurrence, richness, diversity, and the environmental predictor variables were investigated in R using exploratory graphs, k-means clustering, and indirect gradient analysis. Breiman's random forest algorithm was used to predict reef type from species composition identify atypical reef fish communities.
Img 3: A coral fragment outplanted at a restoration site in the Florida Keys.
Img 1: A diverse and healthy reef composed of living corals.
Img 2: A reef composed of dead corals being covered by macro algae.
Habitat type had an effect on species richness and on the variation of Simpson's diversity index. Subregion had very little effect on species richness and Simpson's diversity index. K-means clustering allowed sites to be grouped based on their environmental similarities and dissimilarities. When sites were ordinated by species occurrence records, grouping sites by habitat type provided more separation than grouping sites by environmentally-generated clusters. Sites with atypical reef fish communities and low diversity were identified as being potentially at risk. Identified sites did not appear to be geographically localized, and were not strongly associated with environmental factors.