Dually improving biodiversity and pollination services for enhanced cotton yields and sustainability

Cotton is an economically and culturally important crop throughout the US. Although self fertile, cotton benefits from pollination service, producing significantly larger bolls with more seeds with the application of outcross pollen. Yet growers do not manage cotton for pollinators or employ land managment practices that promote the establishment or long-term stability of pollinator communities. To determine best management techniques for dually increasing cotton yield while preserving important insect biodiversity, we sought to determine the relationship between pollen limitation, pollinator community composition, and aspects of land management in Southern Texas Cotton. Our study had three primary objectives: 1) determine if cotton is pollen limited, 2) determine the relationship between pollen limitation and aspects of pollinator community composition, and 3) determine what aspects of local and regional land use promote diverse and abundant pollinator communities.

To answer these questions we used a combination pollen limitation experiments, pollinator community surveys, and GIS analysis in 12 large-scale South Texas cotton fields. Overall, we found that the South Texas cotton is indeed pollen limited, producing significantly larger bolls with the addition of outcross pollen in comparison to flowers receiving ambient pollination service.  Despite this general finding, we also found a great deal of variation in the degree of pollen limitation between sites. The degree of pollen limitation was closely associated with aspects of pollinator community composition, including insect abundance and richness. Pollinator community composition, in turn, was found to be closely related to aspects of land- use. Surprisingly, no particular land use type was assoicated rich, abundant communities, but rather land use heterogentity at both local and regional scales had sptrong positive effects on pollinator richness and abundance. The strong relationship between land-use, pollination service, and crop yield, may present a unique opportunity to alter management techniques to conserve biodiversity while dually increasing cotton yield.