Improving forest connectivity assessments using tree cover density maps

Abstract

Forests are vital for sustaining biodiversity and regulating climate. However, the fragmentation of these critical ecosystems poses a serious threat to their ecological integrity and the myriad of organisms they support. In this paper we compare the degree of forest connectivity derived via the traditional approach of using a binary forest cover map with a new approach using a grayscale tree cover density map. Because connectivity is scale-dependent, the comparison is repeated for a series of analysis scales. We find that exploiting the additional information on tree cover density improves the precision of forest connectivity estimates. The degree of connectivity was on average 21% lower when using the tree cover density map compared to using the binary forest cover map. Additional benefits of using tree cover density maps are the detection and quantification of subtle temporal changes (gains and losses) and a more refined assessment of hotspots in forest connectivity that cannot be detected with binary maps. Improved assessment and monitoring capabilities can be instrumental to enhancing the design and assessing the efficacy of landscape management and restoration policies to improve forest connectivity. The generic conceptual approach is exemplified using the 2018 Copernicus Tree Cover Density dataset with all assessment tools available in open-source software packages.

Keywords

• Connectivity
• Fragmentation
• Moving window
• Spatial analysis