En general, la diversidad de especies se correlacionó negativamente con el índice ENOS, la precipitación y la anomalía de la precipitación, incluidos los valores acumulativos de uno a seis meses de cada uno. Akodon montensis, Hylaeamys megacephalus y Oligoryzomys nigripes fueron las tres especies más abundantes. La riqueza de especies en las muestras (una sesión en una parcela) varió de cuatro a siete. Se registraron 1,632 capturas, representando 13 especies sigmodontinos. Se calcularon las mismas correlaciones para las tres especies comunes de sigmodontinos. Las correlaciones producto-momento se calcularon entre los parámetros climáticos y de la comunidad, incluidos los valores acumulados para las variables climáticas. El índice mensual de ENOS multivariable y los valores de precipitación se obtuvieron de sitios accesibles en Internet. La diversidad de Shannon y la abundancia general se calcularon para cada muestra. Las parcelas fueron muestreadas durante cinco noches consecutivas, seis veces durante dos años. Se establecieron tres parcelas de captura-marca-recaptura y se clasificaron como la menos, moderada y más degradadas basadas en un análisis de vegetación de varios parámetros. Este estudio evalúa la diversidad de especies y la abundancia general de roedores sigmodontinos, y la variación asociada con las variables climáticas, en tres lugares con diferentes niveles de degradación del hábitat.
Pocos estudios se han centrado en las comunidades de roedores en los márgenes de una ecorregión o en los límites de las distribuciones de las especies, donde la comunidad puede ser más sensible a las variables extrínsecas, tanto bióticas como abióticas. In contrast, Hylaeamys megacephalus abundance was correlated with climatic variables in two habitats, but not the moderately-degraded habitat, and Oligoryzomys nigripes abundance was not correlated with climate in the most-degraded habitat. Akodon montensis abundances primarily were correlated with abiotic (climatic) variables, and the correlations were consistent across habitats (biotic factors). However, individual species are not impacted similarly. First, they are impacted by habitat and secondly, they are affected by climate (ENSO, precipitation). Our analyses of these longitudinal data showed two major effects on sigmodontine species diversity and population. Overall sigmodontine abundances were generally reflective of Akodon montensis abundance, which generally correlated with precipitation (including cumulative amounts). This somewhat counterintuitive result bears further investigation in other sites at ecoregional margins, to determine whether it is a commonly observed pattern, or an exception. The three most abundant species are each near their distributional limits, whereas several less abundant species have distributions that extend well beyond the study area. However, these correlations were not uniform among the three levels of habitat degradation, nor did the three abundant species show similar correlation patterns. Total sigmodontine abundance was positively correlated with the climatic variables. In general, species diversity was negatively correlated with ENSO index, precipitation and precipitation anomaly, including cumulative one- to six-month cumulative values of each. Akodon montensis, Hylaeamys megacephalus and Oligoryzomys nigripes were the three most abundant species. Species richness in the samples (one session on one grid) varied from four to seven. 1,632 captures were recorded, representing 13 sigmodontine species. The same correlations were calculated for the three common sigmodontine species. Product-moment correlations were calculated between community and climatic parameters, including cumulative values for the climatic variables. Monthly Multivariate ENSO Index and rainfall values were obtained from publicly available resources. Shannon diversity and overall abundance were calculated for each sample. The grids were sampled for five consecutive nights, six times during two years. Three mark-recapture grids were established and classified as least, moderately and most-degraded based on an analysis of several vegetation parameters. The study was conducted in northeastern Paraguay, near the western limit of the Upper Paraná Atlantic Forest and near the distributional limits of the three most abundant species in the study sites. This study evaluates sigmodontine rodent species diversity and overall abundance, and variation associated with climatic variables, in three locations with differing levels of habitat degradation. Few studies have focused on rodent communities at the margins of an ecoregion or the limits of species’ distributions, where the community may be more sensitive to extrinsic variables, both biotic and abiotic.