Collaborative Research: Climatic and Anthropogenic Forcing of Wetland Landscape Connectivity in the Great Plains

The presence and persistence of animals in a landscape is a function of the availability of suitable habitat and the ability of individual animals to find this habitat. Thus, in any landscape, animals encounter an arrangement of suitable habitat patches, or stepping-stones, located within a matrix of unsuitable habitat. The spatial arrangement of these stepping-stones is known as a 'habitat network.' Losses of these stepping-stones stemming from human development and climate change can alter these habitat networks, affecting persistence of the species in the face of rapid climate and landuse change. Wetland habitats in the U.S. Great Plains are embedded within a mixed grassland and agricultural landscape. The Great Plains experiences dramatic year-to-year variability in weather. Climate drives surface processes such as the hydrologic cycle, and hydrology is the most important factor controlling the quality of wetland habitats and the presence of wetland habitat networks. Thus the spatial arrangement of wetland habitat networks in the Great Plains is constantly changing; some wetlands (stepping stones) disappear as others reappear. Land use change adds an additional level of complexity. Increasingly, farmers are converting remnant grasslands in the Great Plains to row crops, with most of this conversion occurring in close proximity to wetlands. This loss of grassland habitat interferes with the ability of some organisms to move between neighboring wetlands, while other species tend to avoid wetlands not surrounded by sufficient grassland cover. This award will use the highly dynamic wetland landscapes in the Great Plains as model systems for exploring general principles related to habitat connectivity. In particular, the funds will allow the PIs to examine how both climate change and land use change will likely influence the connectivity of wetland habitat networks into the next century. This study will focus on two groups, water birds and amphibians, as model organisms that vary widely in their abilities to disperse between wetlands. Methods for quantifying habitat connectivity will be adapted from the study of social networks and a branch of mathematics known as graph theory. Temporal series of wetland condition and land use trends from satellite imagery, computer simulations of wetland hydrology, and downscaled climate change projections will be used to: 1) examine the effects of land use change and climate change on the ability of these two groups of animals to disperse between wetlands, 2) identify barriers to these movements, and 3) identify those wetland habitat networks most likely to persist under projected change

Findings from this study will be used in support of regional conservation planning. Results will be disseminated to public-private partnerships like the U.S. Department of Interior's network of Landscape Conservation Cooperatives and the Prairie Pothole, Rainwater Basin, and Playa Lakes Joint Ventures led by the U.S. Fish and Wildlife Service, and to state management agencies and nongovernmental organizations like Ducks Unlimited and The Nature Conservancy in support of their wetland and grassland easement purchasing strategies. This project will support the early- to mid-career development of four co-PIs, all of whom are from under-represented groups. Through support of external training and lab exchanges, a cadre of four Postdoctoral Fellows and one Ph.D. student will be trained in inter-disciplinary, collaborative research. This research will advance the field of Macrosystem Biology by leveraging support from other different disciplines, e.g., advanced hydrologic modeling, atmospheric science, and graph theory to address previously inaccessible biological questions. Methods developed over the course of this project, and general principles potentially discovered, are anticipated to be broadly applicable to conservation of other types of habitat networks, globally.