Land use change alters trait expression in three wild brassica species

Human mediated land use change has dramatically reshaped landscapes on a global scale, altering the communities that exist in these environments and how they interact with one another. In landscapes dominated by agriculture, insects that are unable to utilize crop resources are often locally eradicated, while insects that can utilize these resources can experience population explosions. In recent years scientists have begun to explore the role that landscape context plays in mediating insect services and disservices to crop production. However, few studies have examined the consequences for non-crop plants growing within agricultural matrices. Land use change has been shown to affect insect richness and abundance, not just in crops, but also in these wild communities. We expect these landscape mediated changes in the insect community to affect plant traits. Here we examine if landscape composition drives changes in trait expression in non-crop plants. To test this question, we conducted a greenhouse common garden experiment with three wild brassicaceous species collected from farms that varied in surrounding landscape composition. We measured traits related to defense and reproduction and found significant correlations between landscape composition and trait expression in all three species. The direction of trait expression change and the most predictive landscape type varied by species, but all demonstrated evidence of a fitness cost associated with agriculturally dominant landscapes. This work provides evidence that land use change affects plant traits, and future work will test if insects are the major agent of selection driving this trait change.