Diversidad de arañas del suelo y su relación con ambientes heterogéneos del Parque General San Martín, Entre Ríos, Argentina

The spider community associated to the ground in different environments and its relationship with environmental heterogeneity in the Parque General San Martín was analyzed. Spiders were captured with pit-fall traps in 3 representative environments of the park, for 2 seasons (2011-2012): native forest (BN), exotic forest (BE) and grasslands (P), characterized by graminiform plants. 1,398 spiders were collected (26 families and 120 species/morphospecies). The highest spider abundance was registered in P (678 individuals), followed by BE (501) and BN (219), while species richness was higher in BN. Diversity indexes showed statistically significant differences among the environments sampled. Heterogeneity variables used in this study showed a higher heterogeneity in BN, followed by P and BE as the most homogenous. Eight guilds were registered. All of the guilds were present in BN, while the sensing web weavers were not recorded in the BE, as well as the ambush hunters in P. This work constitutes the first approach about the importance and changes undergone by the diversity of ground spiders in environments with different degrees of heterogeneity, as a result of the advance of exotic species in a park from Entre Ríos.