Carrion increases pollination service across an urban gradient

Abstract

The world is increasingly urban, and urbanization alters the abundance and distribution of resources important to mutualist pollinators. Pollinators require distinct and diverse resources throughout their life cycle, including larval habitat and adult food resources. However, the relationship among urbanization, pollinator resource distribution, pollinator abundance, and pollination service provision are uncertain. Here, we test whether the presence of rat carrion facilitates pollination service to a non-native plant, Ammi majus L. (Apiaceae), by bolstering the pollinator community across an urban gradient. We show that carrion increased pollinator abundance and service provision to focal plants, especially in densely urban landscapes. Specifically, a paired experimental design revealed that in the presence of rat carrion, pollinator abundance increased by more than two-fold and plants received 11.2% greater pollination service across landscapes. Those plants situated in highly urban contexts received the greatest benefits from carrion with the largest abundance of pollinators and highest proportion of viable seed set. We demonstrate how human development facilitates the reproduction of a non-native plant by altering the pollinator community and pollination service provided across an urban gradient. Our findings have both basic and applied implications. First, we show that mutualistic species with complex life histories can provide conduits between various levels of ecosystem processes. Second, we suggest that the removal or reduction of larval habitat may serve as a tool in the management of non-native Apiaceae plants in the upper Midwest.