Pollination services in a social-ecological system: Understanding the impact of land cover on bee populations in a seasonally dry tropical landscape to inform ecosystem service incentive schemes

Background/Question/Methods

Ecosystem services (ES) such as pollination are critical for agricultural and non-managed ecosystems but may be disrupted by certain land cover types within complex agricultural landscapes.  Pollination by native bees is vulnerable to agricultural intensification and management practices, and is a globally threatened service.  Payments for Ecosystem Services (PES) have gained attention as a method of incentivizing land cover and management that maximizes ES provision.  In Costa Rica, PES have been provided to landowners who reforest with agroforestry, native secondary forest, or timber plantations, but there is little data linking these land cover types with specific ES, such as pollination.  We ask: How do the abundance and diversity of bee populations compare in high- elevation pasture, low-elevation pasture, teak plantations, and coffee agroforestry systems in the Nicoya Peninsula of Costa Rica?  Bee abundance and diversity can be used as a proxy for the spatial and temporal availability of pollination services, and will be assessed using standard trapping and sweep net surveys over a two-year period. In addition, we will observe bee visitation of coffee and teak flowers and identify blooming flora in the plots to assess the impact of floral resource availability, and evaluate the influence of landscape context. 

Results/Conclusions

This presentation will discuss results from fieldwork conducted during spring 2013, including the abundance and diversity of bees and the relative temporal availability of floral resources in each land cover type.  Since agricultural land cover types may lack the nesting habitat and floral diversity needed to support bee populations, we expected bee abundance and diversity to decrease with distance from secondary forest in all plots. In addition, we expected this change to be most pronounced in teak plantations and pasture. Results demonstrate that floral resources were present year-round in the secondary forest, but were most abundant during the dry season. Coffee and teak bloom briefly during the rainy season, and had fewer floral resources during the majority of the study. Bee species diversity and abundance were lower in teak plantations compared to other land uses. This study is part of an interdisciplinary evaluation of multiple ES by land cover types in the peninsula and the value attributed to these services by residents.  It will contribute to our understanding of the impact of PES both locally and in the many places worldwide where they are being employed.