Changes in Land Use and Land Cover Along an Urban-Rural Gradient Influence Floral Resource Availability

While several hundred thousand species of insects, mammals, and birds rely on flowers for food or reproduction, a surprising dearth of literature focuses specifically on floral resources. An understanding of floral resource availability is particularly necessary in urban areas, which have recently been proposed as important habitat for declining pollinator populations. In this study, we aim to synthesize existing information and provide new insights about the effects of land use and land cover (LULC) change and urbanization on the distribution, diversity, and abundance of floral resources. Our results suggest that certain LULC types provide more floral resources than others. In particular, urban lands may have higher floral density than agricultural or natural lands. However, we also observed inconsistent findings between studies, and the relationship between urbanization and floral resource availability may vary by city, with this variation possibly due in part to city size, LULC composition, regional biome, and biases in sampling. It appears that cities have the potential to provide an important source of floral resources. However, a complete understanding of the effects of urbanization on floral resources requires that landscape composition and heterogeneity be taken into account. We recommend that more studies estimate floral resource availability at a landscape scale by combining data about LULC composition with data about floral resource availability within various LULC types. These studies should focus specifically on flower communities and be conducted along a full urban-rural gradient.