A distance-decay framework for mapping conservation buffer against devegetation (CBD) using high-resolution google earth imagery

Infrastructure development increasingly pressures vegetation and natural ecosystems. However, traditional buffer zones focus on protecting natural cores rather than addressing infrastructure as a pressure source. This study introduces a distance-decay framework for mapping Conservation Buffer against Devegetation (CBD), which defines buffer boundaries based on actual vegetation response to distance from human infrastructure. Using a two-module approach, we integrated high-resolution Google Earth imagery with spatial analysis of land-use change. Module 1 employed Support Vector Machine (SVM) classification, which outperformed Maximum Likelihood Classification. Module 2 calculated CBD by applying a 2% stability threshold to devegetation rates across concentric distance rings. The framework was applied in Maragheh, Iran, where Yadegaran Park (established in 2013) and a 65-m bridge (2018) were constructed within orchard areas along the Sufichay River. Results revealed CBD of 750 m for the park and 550 m for the bridge, demonstrating differential impacts of patch versus linear infrastructure. Base devegetation rate increased from 14% (2011–2017) to 18% (2017–2024) ( p < 0.0001), indicating cumulative pressure intensification. Vegetation vulnerability patterns shifted: grasslands experienced highest loss (38.4%) in the first period, while shrubs became most vulnerable (27.5%) in the second. This freely available data framework offers an effective tool for evidence-based land-use planning and environmental impact assessment in data-limited regions.