Heather Grab

My research interests sit at the intersection between agricultural production and biodiversity conservation. The expansion and intensification of agriculture is one of the leading causes of biodiversity loss worldwide. At the same time, many of the services upon which agriculture depends are underpinned by diverse agro-ecosystems. When agro-ecosystems are managed poorly, the result is a feedback in which intensification of agriculture leads to a loss of biodiversity, ecosystem services, and increased yield gaps; a negative outcome for both biodiversity and agricultural productivity. Alternatively, ecological intensification of agriculture based on knowledge of the links between agricultural practices and biodiversity can create win-win scenarios. I am currently exploring a number of different areas related to this theme using tools from the molecular to the landscape level.




Landscape drivers of ecosystem services

AppleBeeFanPhylogenyLandscape simplification through agricultural intensification threatens both pollinators and natural enemies, key ecosystem services to agriculture. The objective of my research in this area is to determine how this simplification impacts the abundance and diversity of native bee pollinators and natural enemies in strawberry agroecosystems and to understand how a reduction in these services is expected to impact crop yield. Currently, I am using molecular markers to identify how landscape simplification impacts the phylogenetic diversity of pollinator communities.


Along with an undergraduateAndrena nasonii size variation mentee, I am exploring how resource scarcity in agricultural landscapes can reduce the body size of bees within species and the potential consequences for bee fitness. I am also interested in how mass flowering crops impact pollinator community dynamics and the yield of co-blooming crops.




Local drivers of ecosystem services

Because individual farmers and land managers often have little control of land use practices at the landscape scale that may be impacting ecosystem service providers on their farm, I am exploring the practice of planting native perennial wildflower strips to support pollinators and natural enemies. These wildflower strips are expected to increase parasitism rates of key crop pests and resources for native bees outside of the window of crop bloom. To better understand the potential costs and benefits of these strips for bees I am collaborating with Laura Figueroa to build a visitation network for the wildflower and bee species that also includes information on the potential transmission pathways for several bee pathogens.