Print PageLocal management including agrochemical use and tree pruning influences biodiversity in agroecosystems. However landscape factors such as proximity to forest fragments can also strongly affect species richness and composition. In order to elucidate the factors that affect spider diversity in coffee systems, we sampled leaf litter spiders in a coffee landscape composed of seven forest fragments and a range of coffee management systems in Chiapas Mexico. We then asked how both local management characteristics (e.g. canopy cover, tree richness, leaf litter depth) and landscape characteristics (e.g. distance to forest, percent of forest in the surrounding areas) affected the abundance, richness, and composition of spiders. We selected forty 20 x 20 m plots distributed across the landscape; thirty plots in coffee plantations and ten plots in forest fragments. At the center of each 20 x 20 m plot, we sampled spiders with five pitfall traps arranged in a square meter. In addition, in each plot we measured a number of vegetation and ground cover characteristics (leaf litter depth, canopy cover and soil moisture). We used GIS analysis to examine for each plot the distance to forest and the percent of forest around plots at three spatial scales (50m, 200m, and 500m).
Results/Conclusions
Preliminary results show that at local level spider abundance is influenced by coffee management type but not by leaf litter depth. Specifically, shade coffee plantations showed the highest abundance, where as sun coffee plantations and forests showed similar abundances (20.75,8.42 and 9.32 spiders respectively; p<0.001). Interestingly, forest fragments had the highest values of leaf litter depth but they showed low spider abundance values. In addition, spider richness did not show any relationship with management type or leaf litter depth. Even though spider richness was higher in the shade coffee plantations than in the other two systems, the difference was not significant (shade coffee plantations= 7.2 species,forest= 4.66 species, sun coffee plantations= 3.85 species;p>0.05). Regarding landscape factors, spider abundance was neither related to distance to forest nor to the percent of forest at any scale (p>0.05). Our results suggest that other variables such as slope, soil moisture and ants presence influence leaf litter spider diversity in coffee landscapes.
