Measuring the connectivity contributions of sustainably managed forests in North Carolina.

Background/Question/Methods

Central North Carolina is an epicenter of both private and industrial forestry. Home to rare and endemic understory plant communities, swaths of intact longleaf pine forest, and a suite of threatened and endangered species, this region is also the subject of substantial conservation interest from non-governmental organizations and natural resource agencies. Enhancing landscape connectivity is a major focus of these organizations, especially in longleaf pine habitat which has been heavily fragmented by historic and ongoing resource extraction and land conversion in the Southeast. Climate change and future population growth are expected to exacerbate land use change and further reduce landscape connectivity, prompting additional conservation concern. Both sustainable forest management and habitat restoration efforts can reduce the fragmenting effects of land use change in the Southeast, but the degree of their respective contributions is unknown. We used a landscape change model to forecast the trajectory of forests in central North Carolina across four global change scenarios. We then evaluated how these forests, especially restored longleaf pine and sustainably managed forests, contribute to landscape connectivity using graph theoretic metrics to quantify changes in potential connectivity over time for species with a maximum dispersal distance of 5000m and pine forest habitat preferences.

Results/Conclusions

Both the inclusion of sustainably managed forests and habitat restoration at rates of 1%, 3%, 5%, and 6% of the landscape improved connectivity above the landscape baseline. The number of habitat patches that sustainably managed forest lands added to the landscape and the linkages facilitated by those patches were approximately equivalent to the numbers added/facilitated by a 3% rate of forest restoration. Sustainably managed forests consistently had greater average node sizes across scenarios when compared to all restoration rates, while all rates of restoration had lower average least cost paths between habitat patches. Lower graph density combined with higher average number of links in the 5% and 6% restoration simulations suggest that these two scenarios are most effective at facilitating landscape connectivity, creating a larger and more well-connected network. Ultimately, the connectivity contributions of sustainably managed forests on this landscape were similar to the connectivity provided by a rate of 3-5% land acquisition and restoration. This evaluation of the connectivity facilitated by sustainably managed and restored forests can provide decision support for natural resource managers aiming to enhance landscape connectivity in the study area and highlights the importance of forest restoration and sustainable forest management to promote biological diversity.