Spatial Variability of Landscape Pattern Change following a Ponderosa Pine Wildfire in Northeastern New Mexico, Usa

Forest fires have profound impacts on the spatial distribution of vegetation type and density. This research analyzes the impacts of the 2002 Ponil Fire in New Mexico on landscape patterns using a moving-window analysis of landscape metrics. Categorically derived landscape metrics and a measure of fire severity—the Normalized Burn Ratio—are used to produce a quantitative, spatial distribution of landscape change. While gross land-cover change summaries and landscape-metric changes indicate a more heterogeneous landscape following the fire, the moving-window approach demonstrates the oversimplification of landscape-scale metrics and summaries. The moving-window approach indicates that the majority of areas in the landscape were unchanged in mean patch size, whereas mean (and median) patch size increased according to landscape-level measures. Contrary to expectations, average patch density and richness were also nearly unchanged. The moving-window approach is particularly helpful in analyzing large fires with considerable variability in severity, allowing greater insight into the relationship between fire severity and landscape composition and structure in post-fire landscapes. The moving-window approach also can guide researchers and managers to specific areas of a landscape where large changes have occurred and where evidence for understanding the process driving that change is most likely to be found.