Spiders (Araneae) of the yungas ecoregion from Salta Province (Argentina): pedemountain vs. mountain forest

RUBIO GONZALO; CORRONCA JOSÉ

Sao Paulo

Congreso; 17th International Congress of Arachnology; 2007

The Argentinean Yungas ecoregion, as well as the Paranaense Forest, has a great biological diversity. Three altitudinal and vegetational floors are represented in the Yungas: the pedemountain (PF) (400-900masl); the mountain forest (MF) (800-1500masl) and the mountain woodland (>1500masl). Several authors suggested that the pedemountain has a great biodiversity because it acts as a species refuge of the other yungas altitudinal floors and suffered, in the last decades, a high degradation. Each altitudinal floors are represented and defined by a very special and particular flora, where the mountain forest has the high structured and complex vegetational architecture represented by a high forest with bromeliad, lianas and epiphytes. The aims of this work were to compare the spider community in both altitudinal floors and to prove if close and distant sites of the same vegetational floor of the yungas share a spider community because it is high influenced by the habitat type. One hundred and forty samples were taken during autumn 2006 with a G-vac (Garden-vacuum) in 14 sites between 800-1500masl in the Center region of Salta Province, Argentina. One thousand two hundred and sixty nine spiders were collected of 24 families and 107 species/morphospecies. The spider diversity in both vegetational floors showed significant differences (PF: S=76, n=478, H´=3.59, E=0.83; MF: S=58, n=791, H´=2.76, E=0.68). It confirms the prediction that the pedemountain has the highest diversity in yungas ecoregion. Quantitative and qualitative ecological classification methods arranged the 14 sites into the two vegetational floors, the MF represented by 6 sites and the PF with 8. These analyses showed the same vegetational floor of the yungas shares a spider assemblage. In almost cases, close sites shared similar spider assemblages than the distant ones. The exception was represented by two very close sites belong to pedemountain floor with a high human disturb that showed different spider assemblages between them.