PARENT SESSION
Contributed Oral Session 165: Agroecology: Diversity and Modeling
Friday, August 12, 8:00 AM - 11:30 AM, Meeting Room 521 A, Level 5, Palais des congrès de Montréal
Temporally-dependent effects of region and habitat on spatially partitioned Hymenoptera diversity within a tropical mosaic landscape.
Tylianakis, Jason1, Klein, Alexandra-Maria1, Tscharntke, Teja1, 1 University of Goettingen, Goettingen, Lower Saxony, Germany
ABSTRACT- With the decline in global biodiversity and the concomitant loss of potentially important ecosystem services, an understanding of the factors that govern species richness and the spatiotemporal scales over which these factors operate, are among the most pressing issues facing ecologists today. For the first time we tested simultaneously the effect of spatial and temporal turnover and habitat type on tropical biodiversity, using the experimental placement of standardized nesting structures for bees and wasps (Hymenoptera: Aculeata) in Southwest Ecuador, a global biodiversity hotspot. Hymenoptera are particularly salient from an ecosystem services perspective, as many species are important pollinators of natural and agricultural plants or natural enemies of herbivore taxa. We examined diversity in five habitat types that comprised a gradient of decreasing anthropogenic disturbance, from rice and pasture to coffee/cacao agroforests, abandoned agroforests and forest fragments. There was notable overlap in the communities of different habitat types and regions, indicating that even intensively managed land can provide a valuable contribution to the overall biodiversity of the landscape mosaic. Although highly disturbed habitats showed the highest diversity in some months, their constituent species were frequently generalists, and habitat specificity of Hymenoptera decreased with increasing anthropogenic disturbance. Importantly, there was a significant effect of habitat type on temporal variation in diversity. While intensive cropping systems exhibited higher diversity in certain months, greater species turnover through time in the abandoned coffee and forest plots accounted for the higher overall diversity in these habitats. Overall, spatial and temporal turnover explained 38.6% and 23.1%, respectively, of partitioned regional species richness. Spatial scale of study (either within or between plots) affected the manner in which habitat type, floral diversity and forest cover influenced diversity. This study showed a high importance of spatiotemporal turnover to tropical biodiversity. We emphasize caution in the estimation of biodiversity at only one spatiotemporal scale and highlight the large contribution of managed land to overall biodiversity.
Key words: additive partitioning, hymenoptera, temporal scale, trap nest