Effects of habitat fragmentation on non-volant small mammals of the interior Atlantic forest of Eastern Paraguay
de la Sancha, Noe
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The goal of my dissertation research was to improve the understanding of the Atlantic Forests (AF) of South America by applying the knowledge gathered from Paraguay’s forest remnants to the rest of the AF remnants. Specifically, my aims were to increase our knowledge of the non-volant small mammals in eastern Paraguay forests; examine the relationship between species and forest remnant area; compare biodiversity between Paraguay and Brazil; and examine biodiversity patterns throughout the AF through metacommunity and latitudinal structure analyses. By examining this system I achieved the following: 1) I conducted standardized surveys for forest remnants of Paraguay at 40 localities, in 4 forest remnants; 2) I established species-area relationships for four of the major forest remnants of Paraguay; 3) I uncovered similarity relationships between different coastal and non-coastal Brazilian and Paraguayan sites; 4) I identified differences in biodiversity among different-sized forest remnants, tropical and temperate sites, and coastal and inland remnants for a variety of diversity components; 5) I categorized the metacommunity structure of the small mammal assemblages of the AF; 6) and finally, I detected latitudinal relationships between biodiversity and assemblage structures throughout the AF. In Chapter 2, I modeled richness of non-volant small mammals in remnants of AF, utilizing studies and survey information from the Brazilian AF. A three-dimensional model was built to predict number of species as functions of trapping effort and remnant size. Unlike traditional species-area models, this three-dimensional model allowed for the incorporation of different trapping efforts, plus it recovered a nonlinear species area relationship. In Chapter 3, I examined biodiversity at two scales: 1) within the forest fragments of Paraguay, comparing the various grids sampled; and 2) between forest fragments of Paraguay and Brazil. I employed a multivariate approach to examine how each component of biodiversity indices behaved as a function of scale, forest size, and locality. In Chapter 4, effects of latitude and metacommunity structure were assessed for remnants from northeastern Brazil down to eastern Paraguay. The aim was to understand how fragmentation may affect large-scale patterns of the Atlantic Forest, and in doing so, to understand how Paraguay fits into the structural framework of this system.