US-IALE 2018

AUTHORS: Noé U. de la Sancha, Department of Biological Science, Chicago State University; Nancy E. McIntyre, Department of Biological Sciences, Texas Tech University; Sarah A. Boyle, Department of Biology, Rhodes College

ABSTRACT: Loss of habitat has been identified as one of the main contributors to biodiversity loss and extinction. This is especially true for tropical and subtropical rainforests throughout the world, where forest fragmentation is compromising connectivity in formerly continuous habitats. The Atlantic Forest of eastern Paraguay has experienced extreme deforestation in the past 60 years, resulting in only 8-12% of its original forest cover. In this study, we present a network analysis to identify important forest remnant patches in eastern Paraguay. We quantified structural connectivity for forest remnants at five nested scales, with networks ranging from those remnants at least 5 ha (n = 27,804 remnants) up to remnants at least 25 ha (n = 7579 remnants). We used eight graph theory metrics to assess aspects of network complexity, dispersal-route efficiency, and individual remnant importance in supporting connectivity. Patterns of connectivity varied based on the network, but all analyses revealed that the Atlantic Forest remnants of eastern Paraguay comprise a complex network with high path redundancy. Furthermore, we found that connectivity was constrained for organisms incapable of traveling at least 12 km (farthest nearest-neighbor distance). We were able to identify a few remnants that were consistently recovered as valuable connectivity stepping-stones. We conclude that structural connectivity metrics can be examined at the regional scale to identify important forest remnants for conservation.