Spatial Modeling of Change in Rocky Mountain Grasslands

由于耕种、开发和其他土地利用，美国各地的草原正在减少。干旱的西部山区草原面积达数十万公顷，为牲畜和野生动物提供了重要的饲料，也为人们提供了娱乐机会和家园。最近的国家评估表明，由于不可持续的土地利用，山地草原可能会受到威胁，但获得的信息很少。一些证据表明，由于树木的入侵和发展，山地草原正在退化，并正在因外来物种的入侵而退化。然而，这种变化的证据并不是基于景观尺度的、系统的空间分析，对山地草原变化的原因仍然知之甚少。这项研究项目的重点是科罗拉多州西南部圣胡安山脉的山地草原。研究人员将使用原始土地调查记录、重复航空摄影、重复地面摄影、野外采样和地理信息系统来记录和绘制该山脉草原的变化。将解决的关键问题包括：自欧美人定居以来，山地草原面积是减少了还是增加了？如果草原面积发生了变化，变化是否集中在特定的地理环境中？如果草原面积发生了变化，这种变化是否与特定的土地利用或气候变化有关？使用基于地理信息系统的空间建模，预测哪些草原地区最容易受到进一步变化的影响？该项目的目标是确定土地使用如何影响山地草原，目的是在维持人类利用的同时保持草原生产力和生物多样性。该项目将提供数据、地图和空间模型，帮助各机构和社区团体制定政策。数据将纳入在线规划数据库和植被数据档案。将通过新闻发布、采访和公开演示来鼓励使用这些数据。

Grasslands are declining throughout the United States due to cultivation, development, and other land uses. Mountain grasslands in the arid West cover hundreds of thousands of hectares, and provide key forage for livestock and wildlife as well as recreational opportunities and homesites for people. Recent national assessments suggest that mountain grasslands may be endangered due to non-sustainable land uses, but little information is available. Some evidence suggests that mountain grasslands are declining in extent due to tree invasion and development, and are being degraded by invasion of non-native species. Yet, this evidence of change is not based on landscape-scale, systematic spatial analysis and causes of changes to mountain grasslands remain poorly understood. This research project focuses on mountain grasslands in the San Juan Mountains in southwestern Colorado. The researchers will use original land survey records, repeat aerial photography, repeat ground photography, field sampling, and GIS to document and map changes to grasslands in this mountain range. Key questions that will be addressed include the following: Has mountain grassland area declined or increased since EuroAmerican settlement? If grassland area has changed, are changes concentrated in particular geographic settings? If grassland area has changed, are the changes related to particular land uses or climatic change? Using GIS-based spatial modeling, which grassland areas are predicted to be most vulnerable to further change? The goal of the project is to identify how land uses are affecting mountain grasslands with the aim of maintaining grassland productivity and biological diversity while sustaining human uses. The project will provide data, maps, and spatial models that will aid policy formulation by agencies and community groups. Data will be incorporated into online planning databases and vegetation data archives. The use of these data will be encouraged through news releases, interviews, and public presentations.