Local and landscape constraints on coffee leafhopper diversity

Background/Question/Methods

The intensification of agriculture drives many ecological and environmental consequences including impacts on crop pest populations and communities. These changes are manifested at multiple scales including small-scale management practices and changes to the composition of land-use types in the surrounding landscape. While various taxonomic groups have been investigated with regards to local management and landscape factors, few studies have looked at how leafhoppers respond to both local and landscape management level effects simultaneously. In this study, we sought to examine the influence of local and landscape-scale agricultural factors on a leafhopper herbivore community in Mexican coffee plantations. We sampled leafhopper (Order: Hemiptera; Family: Cicadellidae) diversity in 38 sites from nine coffee plantations of the Soconusco region of Chiapas, Mexico. Local factors related to management intensity such as coffee density, shade tree density, shade tree richness, proportion of Inga spp., herbaceous ground cover and height were measured. Landscape factors such as forest, low-shade, medium-shade, and high-shade coffee land-use types within a 100, 250, 500, 500 and 1000m radium surrounding each sampling site were obtained. Habitat diversity for each of these sites was also calculated.

Results/Conclusions

Local management factors such as coffee density, branches per coffee bush, tree species and density were not important in explaining leafhopper abundance and richness, shade management at the landscape level and elevation significantly affected leafhoppers. Specifically, the percentage of low-shade coffee in the landscape (500m radius surrounding sites) increased leafhopper richness and total abundance. Additionally, Shannon’s diversity of leafhoppers was greater at higher elevations. Our results show that abundance and richness of leafhoppers are greater in simplified landscapes, thereby suggesting that these landscapes will have higher pest pressure and may be more at-risk for diseases vectored by these species in an economically important crop.