OOS 14-8
The implications of landscape changes and connectivity for biodiversity and conservation in the southern Great Plains
The Great Plains is the largest and most fragmented region in North America. Although less than thirty percent of its original grassland cover remains, this region is expected to continue to experience dramatic changes in land use over the next several decades, which will likely have important negative consequences for native fauna. We evaluated changes in terrestrial connectivity for grassland species in Oklahoma using current and future land-cover maps. Future land-cover projections were derived from four storylines of the Intergovernmental Panel on Climate Change Special Report on Emission Scenarios, which are orientated along two axes, one focused on economic growth versus environmental protection, and one focused on global versus regional development. We used a recently developed functional connectivity index called the Equivalent Connected Area (ECA), defined as the size of a single patch (maximally connected) that would provide the same probability of connectivity than the actual habitat patterns in the landscape. The temporal changes in ECA were directly compared with the changes in total habitat area. We focused on changes in grassland cover at the county level for the period 2006-2050, considering both changes in the grassland spatial pattern and in the average permeability of the landscape matrix.
Results/Conclusions
Our preliminary results showed that connectivity will decrease over most of Oklahoma from 2006-2050, with temporal changes in ECA values for the four studied scenarios lower than -10% in about 75% of the counties. In addition, we found significant differences in connectivity between landscape scenarios, with a greater difference between the most economically and globally orientated scenario and the other scenarios. Finally, the largest individual changes in connectivity were found for species with short dispersal distances, and values tended to be lower as dispersal distances increases, although these differences were not significant. Our results indicate that future land use changes will negatively affect biodiversity by decreasing landscape connectivity. The results also suggest that the main cause of this decrease in future connectivity is loss of grassland cover, which was (to a greater extent) independent of landscape scenario and species’ dispersal ability.