PS 59-6
The effect of local practices and landscape composition affect local parasitoid populations.

Friday, August 15, 2014
Exhibit Hall, Sacramento Convention Center
Damie Pak, Ecology and Evolutionary Biology, University of Mchigan, Ann Arbor, MI
Aaron Iverson, Ecology and Evolutionary Biology, University of Mchigan, Ann Arbor, MI
Katherine K. Ennis, University of California, Santa Cruz, Santa Cruz, CA
David J. Gonthier, School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI
John Vandermeer, Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI
Ivette Perfecto, School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI
Background/Question/Methods

Over the past several decades agricultural lands have become increasingly intensified. This has consequently lead to a deterioration in biodiversity, increased habitat homogeneity, and the degradation of important ecosystem services such as biological control. In many agroecosystems, such as coffee farms, parasitoid wasps serve important roles in controlling common pests, such as aphids and scales. However, rearing and releasing parasitoids may prove difficult. Therefore, augmenting natural populations in farms may be an important means of control, allowing farmers to decrease pesticide use. In this study, we addressed how landscape composition and management techniques in 38 Mexican coffee farms influence the parasitoid community. At the local scale we considered abiotic factors, as well as those pertaining to plant diversity and structure. At the landscape level, we assessed the land-use in the surrounding areas.

Results/Conclusions

Overall, we observed that the abundance and diversity (richness and evenness) of parasitoid wasps were influenced by both their immediate surroundings (local scale) and the quality of the surrounding landscape. At the local scale, vegetation structure was an important determinant of the parasitoid community, and we observed tree girth (basal area) and tree density to be most positively correlated. The diversity of the canopy trees was also an important predictor. Interactions with local organisms, such as ants, also has a role in influencing the parasitoid community. In terms of landscape composition, more high-intensity farms in the surrounding areas had a negative impact. In conclusion, to augment or conserve natural enemies, such as parasitoids, it is important to consider environmental factors at both local and regional scale. Furthermore, both vegetation structure and diversity may play important roles.