Monitoring rangelands by identifying the departure of contemporary conditions from long-term ecological potential allows for the disentanglement of natural biophysical gradients driving change from changes associated with land uses and other disturbance types. We developed maps of ecological potential (EP) for shrub, sagebrush (Artemisia spp.), perennial herbaceous, litter, and bare ground fractional cover in Wyoming, USA. EP maps correspond to the potential natural vegetation cover expected by environmental conditions in the absence of anthropogenic and natural disturbance as represented by the greenest and least disturbed period of the Landsat archive. EP was predicted using regression tree models with inputs of soil maps and spectral data associated with the 75th percentile of the Normalized Difference Vegetation Index in the Landsat archive. We trained our EP models with 2015 component cover maps on ecologically intact sites with relatively lower bare ground than expected. We generated departure of vegetation cover by comparing the EP and 2015 fractional cover. The departures represent land cover change from potential land cover and/or within-state changes in 2015. Next, we converted EP and 2015 fractional cover maps into thematic land cover and evaluated departure to determine if it was great enough to result in land cover change. The 2015 conditions showed reduced shrub, sagebrush, litter, and perennial herbaceous cover and increased bare ground relative to EP. Known disturbances, such as energy development, fires, and vegetation treatments, are clearly visible on the departure maps, but not on EP component maps. The most frequent departure from EP land cover was shrubland conversion to grassland. Land cover departures can be explained only in small part by known disturbance, and instead are ostensibly related to climate and land management practices. These drivers result in land cover departures that broadened the ecotone between shrubland and grassland relative to EP.

通过识别当代条件与长期生态潜力的偏离来监测牧场，可以使自然生物物理梯度解开，从而驱使变化与土地用途和其他干扰类型相关。我们为灌木，鼠尾草（Artemisia）开发了生态潜力（EP）地图spp。），多年生草本，凋落物和裸露的地面覆盖物，位于美国怀俄明州。EP地图对应于在没有人为和自然干扰的情况下环境条件预期的潜在自然植被覆盖，如Landsat档案中最绿色和最少干扰的时期。EP是使用回归树模型预测的，该模型具有输入的土壤图和与Landsat档案中的75％归一化差异植被指数相关的光谱数据。我们在2015年裸露地面低于预期的生态完好的地点训练了我们的EP模型和2015年的组件覆盖图。通过比较EP和2015年部分覆盖率，我们得出了植被覆盖率的偏离。偏离代表2015年潜在土地覆盖的土地覆盖变化和/或州内变化。接下来，我们将EP和2015年部分覆盖图转换为主题土地覆盖，并评估了偏离度，以确定其是否足以引起土地覆盖变化。2015年的情况表明，与EP相比，灌木，鼠尾草，凋落物和多年生草本植物覆盖减少，裸露地面增加。已知的干扰，例如能量发展，火灾和植被处理，在离场图上清晰可见，而在EP组件图上则不清晰。离开EP土地覆盖最频繁的是灌木丛转换为草地。土地覆盖的变化只能通过已知的干扰来作一小部分解释，而表面上与气候和土地管理实践有关。这些驱动因素导致土地覆盖变化，相对于EP，拓宽了灌木和草地之间的过渡带。