Spatial-temporal analysis of the landscape structure surrounding Cerrado conservation units without a buffer zone

Abstract

This study evaluated the landscape structure surrounding strictly protected conservation units (CUs) in the Cerrado biome that lack designated buffer zones, in comparison with landscapes outside these units across spatial and temporal scales. For the spatial analysis, 18 fully encompassed Cerrado CUs and 18 randomly selected external points within the biome were assessed for the year 2022. For temporal analysis, 9 CUs and 9 random points were analyzed for the years 2010 and 2022. In all cases, 10-km buffers were delineated, and land use as well as land cover maps were generated. Landscape structure was quantified using percentage of class (PLAND), edge density (ED), and effective mesh size (MESH) metrics. Comparisons within groups were performed using the Mann-Whitney, Student’s t, and Wilcoxon tests. In the spatial analysis, areas surrounding CUs exhibited a low proportion of Cerrado cover (median≈29.8%) and did not differ significantly from external areas in PLAND or MESH. However, they presented significantly higher ED values, indicating greater fragmentation and increased exposure to edge effects around the CUs. In the temporal analysis, PLAND and MESH did not differ significantly between 2010 and 2022, whereas ED increased across all landscapes, reflecting the intensified fragmentation occurring near the CUs over time. These results demonstrate that the CUs are embedded in landscape contexts that are structurally unfavorable for conservation, and suggest that the absence of buffer zones, coupled with weakened legal instruments, may perpetuate and aggravate this situation.