Land Use and Climate Influence Marshes in the Northern Prairie and Parkland Region

Abstract

I evaluated the association between waterbird communities and agricultural activity at 48 non-permanent wetlands, and waterbird response to inter-annual climate variation at 24 non-permanent wetlands. I found six distinct assemblages of waterbirds, each with indicator species reflective of disturbance, landscape (500 m), and site level variables. The 6 assemblages can be predicted using a combination of landscape (forest cover, water and wetlands, and pasture) and site level variables (robust emergent vegetation, woody vegetation and maximum water depth), but differences between natural regions account for more variation than non-natural cover. Results indicate waterbird community composition is undergoing a shift from multiple distinct assemblages that have specialist and sensitive species to assemblages that are made up of common, generalist species, due to increased agriculture in the landscape. I also found that waterbird community composition is sensitive to variation in climate. Between 2014 and 2015, waterbird community composition differed with natural region, disturbance level and wetland class, but the only significant interaction occurred between natural region and year. It appears that the types of changes in composition provoked by inter-annual variation in climate are largely orthogonal to changes that occur in response to agricultural disturbance. These results suggest certain aspects of waterbird community composition can be effective at indicating ecological condition in the Parkland and Grassland natural regions, while being relatively insensitive to inter-annual climate variation, especially if tools are tailored to natural region.