Patterns of small mammal diversity in fragments of subtropical Interior Atlantic Forest in eastern Paraguay

The deforestation of eastern Paraguay is a relatively recent phenomenon, starting as early as the 1940s. Assuming that larger forest fragments retain mechanisms and patterns of biodiversity resembling the original forests, understanding these patterns is valuable for comparative, management, and conservation purposes. In this study, I document diversity patterns in four of the largest reserves of subtropical rainforest in eastern Paraguay as part of a 3-year field study. Forty grids, totaling 31,600 trap nights per reserve, resulted in 19 captured species. Spearman correlations were used to understand effects of distance to edge, and various diversity metrics and multivariate analyses were implemented to compare assemblages between remnants. Trapping revealed an increase in biodiversity toward forest edges. Medium-sized remnants showed the highest diversity (D) and evenness (J). Statistically significant differences were found between and among forest fragments. Given that biodiversity includes both richness and abundances, high biodiversity metrics are not the best indicator for ecosystem health, as population explosions closer to edges result in greater biodiversity. More edge, more biodiversity. Thus, more emphasis needs to be given to understanding the natural history of native fauna and common assemblage patterns when addressing conservation and management strategies.