Effects of land-use and disturbance on pollinators in wetlands

While pollinators and wetlands both provide important ecosystem services (e.g., the pollination of flowering plants and improving water quality), the relationship between the two is not well understood. Wetland quality can determine the local floral community, which likely mediates local pollinator populations. In this study, we investigated how land-use, including a gradient of urban development at the landscape scale, and anthropogenic disturbance affects pollinators in wetlands. We surveyed the abundance and diversity of plant communities in a range of different wetlands across two years. We also measured abiotic factors, such as water quality, light availability, and temperature for insights into the relationships between wetland and pollinator health. Among our surveyed sites, surrounding urban land-use had little effect on pollinator abundance or diversity within wetlands. In fact, urban land-use in a 1-km radius around wetlands was associated with a higher flowering plant abundance and diversity and had the largest abundance of pollinating insects, due to management within the wetlands. In that study, the biotic factors of plant species richness and abundance were the primary drivers of pollinator abundance and diversity, while abiotic factors, such as light availability, temperature, and humidity were not significantly associated with pollinators. We also found that the wetland with the highest proportion of surrounding natural land-use had the most unique pollinator community composition. In a second study, we found that anthropogenic disturbance played a significant role in water quality, where more disturbed sites had lower total organic content in the water. We also saw that disturbance affected the composition of the plant community. However, the response of the pollinator community was not directly related to the biotic and abiotic attributes we measured. Instead, the response of the pollinators was context dependent in different levels of disturbance. Our work has implications for the management of wetland habitats to promote pollinating insects, and also illustrates the impact of disturbance on these important systems.