Forest fragments modulate the provision of multiple ecosystem services.
Agricultural landscapes provide the essential ecosystem service of food to growing human populations; at the same time, agricultural expansion to increase crop production results in forest fragmentation, degrading many other forest-dependent ecosystem services. However, surprisingly little is known about the role that forest fragments play in the provision of ecosystem services and how fragmentation affects landscape multifunctionality at scales relevant to land management decisions. We measured the provision of six ecosystem services (crop production, pest regulation, decomposition, carbon storage, soil fertility and water quality regulation) in soya bean fields at different distances from adjacent forest fragments that differed in isolation and size across an agricultural landscape in Quebec, Canada. We observed significant effects of distance-from-forest, fragment isolation and fragment size on crop production, insect pest regulation, and decomposition. Distance-from-forest and fragment isolation had unique influences on service provision for each of the ecosystem services we measured. For example, pest regulation was maximized adjacent to forest fragments, while crop production was maximized at intermediate distances-from-forest. As a consequence, landscape multifunctionality depended on landscape heterogeneity: the range of field and forest fragment types present. We also observed strong negative and positive relationships between ecosystem services that were more prevalent at greater distances-from-forest. Synthesis and applications. Our study is one of the first to empirically measure and model the effects of forest fragments on the simultaneous provision of multiple ecosystem services in an agro-ecosystem at the landscape and field scales relevant to landowners and managers. Our results demonstrate that forest fragments, irrespective of their size, can affect the provision of multiple ecosystem services in surrounding fields, but that this effect is mediated by fragment isolation across the landscape. Our results also suggest that managing habitat fragmentation and landscape structure will improve our ability to optimize ecosystem service provision and create multifunctional agricultural landscapes.