Ecological refugia enhance biodiversity and crop production in dryland grain production systems

Abstract

Meeting global food demand while reducing biodiversity loss will require strategies that quantify and minimize conservation and production tradeoffs in agroecosystems. Ecological refugia (non-crop habitat patches) were identified in three dryland grain production systems in the Northern Great Plains and assessed for their capacity to enhance biodiversity, crop yield, and crop quality. A radial design of six 100–200 meter transects originating from the refugia and extending into crop fields was used to assess trends in plant and arthropod diversity with increasing distance from the refuge center. Plant species diversity significantly declined with distance from established refugia into crop fields in all years sampled and from a newly established refuge by the third year of data collection. Arthropod taxon diversity declined significantly with distance from refugia on two organic farms but not on a conventional farm. Fields with a refuge hosted a higher abundance of arthropods belonging to Coleoptera than fields without a refuge. Distance from refuge was the most important variable explaining grain yield and grain quality in a random forest model. Yield significantly declined with distance from refugia while grain nutritional quality, based on protein content, iron concentration, and polyphenol concentration, significantly increased with distance from refugia. Overall, ecological refugia enhanced farmland biodiversity and provided tradeoffs for marketable crop production. Moving forward, ecological refugia could serve as a multi-objective conservation practice to integrate food production and conservation goals in agroecosystems.