ABSTRACT
Patterns of land use are changing dramatically in the Orinoco region of Colombia, including extensive commercial forestation of Pinus caribaea, Acacia mangium, and Eucalyptus pellita that are replacing savannas, with unknown consequences for biodiversity. We studied the effects of E. pellita plantations on the diversity of epiedaphic carabid beetles (Carabidae) sampled with pitfall traps at El Vita (Vichada) and Villanueva (Casanare). Furthermore, we assessed stand structure data (basal area, and canopy cover), and soil physical and chemical properties to explain differences in ground beetle composition using redundancy analysis (RDA). We compared diversity and species turnover using Hill numbers and Bray-Curtis dissimilarity, respectively. Low differences in richness were observed between savannas and plantations (at El Vita) and between pastures and plantations (at Villanueva). In general, carabid richness was significantly (not overlap in 95% confidence intervals) higher during the rainy season, and in young plantations than in other habitats. Variation in carabid species composition was mainly explained by a gradient of volumetric humidity, number of trees, basal area at El Vita and pH, nitrogen content of the soil, number of trees, soil clay content, and area of exposed ground at Villanueva. Thirteen carabid (which eight are commons in natural forests) species were identified as indicators of 3- and 14-year-old E. pellita plantations and pastures. Results suggest a strong response of ground beetles (Carabidae) to changes in land use, seasonality, and plantation age. Further research is needed to better understand how landscape heterogeneity, and distance to contiguous of natural habitats, influences biodiversity.
