Land use change and pollinator extinction debt in exurban landscapes

Abstract

Abstract For the first time in more than a century, people across the planet are migrating en mass from cities to rural areas. In this process of ‘exurbanisation’ humans are rapidly converting natural and agricultural regions into low‐density housing. Despite the scale of this exurban development and its potential negative impact on biodiversity, little is known about how this specific type of land conversion impacts wild pollinators. In this study, we conduct an extensive survey of the wild pollinators of the peach agroecosystem and investigate the impact of current and historic land use at multiple spatial scales on pollinator community composition within agroecological landscapes that have recently undergone exurban development. We reveal that the overall composition of the wild pollinator community is significantly associated with current local agricultural and natural land cover. Specifically, local agricultural land use was associated with ground‐nesting bee community composition, whereas natural lands were associated with cavity‐nesting bee composition, revealing that nesting materials drive community composition for these two groups in exurban habitats. In contrast, community composition for butterflies and flies, which made up the smallest proportion of our communities, were not strongly associated with any particular land use type, likely due to their non‐central place foraging strategy. Most interestingly, our results indicate that historic land use remains a significant factor impacting the current abundance of all pollinators in the peach agroecosystem, offering the first evidence of extinction debt in this rapidly expanding exurban landscape.