CNH: Slowing the Expansion of Woodlands and Increasing the Resilience of Grasslands in the Southern Great Plains

CNH：减缓林地扩张并增强南部大平原草原的恢复力

• 批准号: 1413900
• 负责人: Bradford Wilcox
• 金额: $ 137万
• 依托单位: Texas A&M AgriLife Research
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1413900&HistoricalAwards=false
• 关键词: CNH; Slowing; Expansion; Woodlands; Increasing

What determines the boundaries between grasslands and shrublands or forests is of major scientific interest, particularly since these boundaries can shift over time, sometimes relatively swiftly and seemingly permanently. In large areas of the central and western U.S., woody plants have been spreading into grasslands. Previous research has implicated change in climate and grazing pressure as likely contributing factors. This project extends that work to include effects of governmental policies and social attitudes on the use of fire to keep grasslands open, and to include the impacts of conversion between grassland and woodland on ecological services and resultant economics. Researchers will compare three regions with contrasting degrees of woody encroachment in Kansas, Oklahoma, and Texas to test the hypothesis that changes between grassland and woodland are driven by interactions between fire and grazing regimes that are constrained by policy and culture. The project will provide web-based educational materials, workshops, and tools for private landowners, extension agents, USDA staff, and K-12 science teachers. Results are expected to enhance the scientific basis for maintaining economically valuable grasslands in rural America.This project will examine the interactions between social and biophysical processes on wildlands in the Southern Great Plains in the context of a novel social-ecological framework. This framework is centered on grassland state changes resulting from woody plant encroachment, and elucidates the socio-ecological properties that emerge when feedbacks, thresholds, and nonlinearities are accounted for. To test the hypothesis that grassland-to-woodland state changes are driven by interactions among fire and grazing regimes that are constrained in space and time by society, policy, and regulations constraining the use of prescribed fire, research will combines empirical biophysical, social, and economic research within a dynamic, iteratively evolving agent-based model (ABM) linked to land cover. This ABM will analyze the factors that influence decision-making by land managers with respect to the use of prescribed fire as a management tool; forecast changes in regional woody plant cover and ecosystem carbon mass under different scenarios of fire use; project the effects of change between grasslands and woodlands on portfolios of ecosystem services including forage production, groundwater recharge, stream flow, and carbon sequestration; and translate changes in ecosystem services into economic metrics.

决定草原和灌木丛或森林之间边界的因素具有重大的科学意义，特别是因为这些边界可以随着时间的推移而变化，有时相对迅速，似乎是永久性的。在美国中西部的大部分地区，木本植物已经蔓延到草原。以前的研究表明气候变化和放牧压力可能是影响因素。该项目将这项工作扩展到包括政府政策和社会态度对使用火保持草原开放的影响，并包括草原和林地之间的转换对生态服务和由此产生的经济的影响。研究人员将比较堪萨斯、俄克拉荷马州和得克萨斯州的三个木本入侵程度不同的地区，以检验草原和林地之间的变化是由受政策和文化约束的火灾和放牧制度之间的相互作用驱动的假设。该项目将为私人土地所有者、推广机构、美国农业部工作人员和K-12科学教师提供基于网络的教育材料、研讨会和工具。结果预计将提高科学基础，保持在农村America.This项目具有经济价值的草原将研究社会和生物物理过程之间的相互作用，在一个新的社会生态框架的背景下，在南部大平原的荒地。这个框架是集中在草地状态变化所造成的木本植物入侵，并阐明了社会生态特性时出现的反馈，阈值和非线性占。为了验证这一假设，即草地到林地的状态变化是由火灾和放牧制度之间的相互作用所驱动的，这些制度在空间和时间上受到社会，政策和法规的限制，限制使用规定的火灾，研究将结合经验生物物理，社会和经济研究，在一个动态的，迭代发展的基于代理的模型（ABM）与土地覆盖。该ABM将分析影响土地管理者使用规定的火作为管理工具的决策的因素;预测在不同的火使用情景下区域木本植物覆盖和生态系统碳量的变化;预测草原和林地之间的变化对生态系统服务组合的影响，包括饲料生产、地下水补给、河流流量和碳固存;并将生态系统服务的变化转化为经济指标。