Effect of habitat disturbance on pollinators' diversity and composition in the temperate forest of Southern South America

MORALES, C. L.; C. QUINTERO AND M. A. AIZEN

Ribeirao Preto

Conferencia; 8th IBRA International Conference on Tropical Bees and VI Encontro sobre Abelhas; 2004

Habitat disturbance can have profound effects on many components of forest biota including pollinator assemblages. These play a vital function in angiosperm reproduction and in fruit production, as well as in maintaining the genetic diversity in plant populations. Here, we compared richness, abundance, diversity and composition of pollinator's faunas in general, and bees in particular, between disturbed and undisturbed paired sites, in 4 different forest types, along a precipitation gradient in NW Patagonia (Argentina). Our results showed that crude pollinators richness was higher in disturbed sites. Nevertheless, there was not a consistent pattern in rarefied richness. That is, most variation in pollinators as well as bees' richness was driven by higher abundance in disturbed sites. On the contrary, the expected richness in undisturbed sites as a whole, was higher than in disturbed sites. In terms of composition, disturbed sites are more similar among each other than undisturbed sites, both in term of pollinators and bee composition. Regarding the whole pollinators assemblage, the highest similarity among sites is determined by the forest type. On the other hand, regarding bees composition, the highest similarity is determined by habitat units. In sum, all these results demonstrated that habitat disturbance leads to a higher species homogeneity, in particular of the bee fauna. Therefore, our results suggest that the major effects of habitat disturbance are on beta diversity, and to a lesser extent on alpha diversity.