Latitude-enhanced species-area relationships for conservation planning

Abstract

Context: Species-area relationship models are useful in conservation planning; however these models could be strengthened with the addition of a latitudinal factor. Objectives: We built latitude-enhanced species-area relationship models to predict species richness for a variety of common taxa in the eastern United States at local to regional scales. Methods: We used data from complete surveys of East Coast parks in the United States to build latitude-enhanced species-area relationship models for amphibians, birds, freshwater fish, mammals, marine fish, plants, and reptiles. We used data from the published literature and United States Fish and Wildlife Refuges to independently test the accuracy of the models. We demonstrated the utility of all modeled taxa within selected East Coast Protected Areas of the United States. Results: Our models explained 35–91% of the variation in surveyed species richness, with marine fish, freshwater fish and reptile models exhibiting the strongest relationships (pseudo-R2 = 0.91, 0.66, and 0.70, respectively). Latitude had the strongest influence in the amphibian model. During accuracy testing, all taxa exhibited significant agreement between observed and predicted species richness and explained 75–97% of the variation. Our demonstration showed that for two similarly sized US Protected Areas, the parcel l.25° lower in latitude would likely have one more bird species, four more plant species, and an additional amphibian species. Conclusions: The latitude term added value to the species-area relationship models for most taxa and proved useful for conservation and urban planning in local to regional sized areas of the East Coast of the United States.