Impacts of Using Priority Species Lists in Video Surveys on Estimates of Biodiversity

Resource limitations often allow only priority species to be counted in video surveys focusing on major fisheries species.  In light of the movement toward an ecosystem approach to fisheries management, we investigate how the use of priority species lists might impact perceived changes in biodiversity.  Using data from a video survey on reefs in the Gulf of Mexico for years where all fish were counted, we estimated multiple diversity measures (species density, richness, and evenness) at each sampling location, separately for full and priority species lists.  After observing that correlations for all diversity measures between full and priority species lists were positively related to the number of species in the list, we used a Monte Carlo approach to generate distributions of correlations for random lists containing the same number of species as the empirical lists.  For all empirical lists, correlations for species density and species evenness were much lower than the mean of the randomly generated lists, while empirical species richness estimates were similar to random estimates. Further analyses revealed that species lists composed of the most common species performed better than lists composed of rare species or species evenly or randomly selected along a gradient of species-prevalence.