Long term impacts of grass invasions and fire on community change and plant soil feedbacks

草丛入侵和火灾对群落变化和植物土壤反馈的长期影响

• 批准号: 1029168
• 负责人: Carla D'Antonio
• 金额: $ 56.5万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1029168&HistoricalAwards=false
• 关键词: Long; term; impacts; grass; invasions

Over the past twenty years, scientists, land managers and the public have come to recognize the dramatic consequences of species invasions. Despite this recognition, few studies have documented long-term ecosystem consequences of invasions when those invasions go unchecked. The proposed research evaluates long-term impacts of fire-promoting grasses in seasonally dry woodlands in Hawai'i. These grasses, originally introduced as pasture forage, escaped into wildlands where they promote the spread of fire. Native species in these sites are not fire-adapted resulting in a dramatic loss of native species and strongly altered nutrient cycling including losses of nitrogen, a critical resource for plant growth. The proposed research uses observations and experimentation to evaluate how invader-induced changes in ecosystem nitrogen cycling that were well documented in the 1990s, have changed over time since invasion and what the consequences of current growth conditions are for native species. Experiments will evaluate nitrogen loss rates over time, changes in soil carbon pools and the consequences of these changes for native and non-native species. Fire-promoting non-native grasses are a significant management concern in arid and semi-arid ecosystems. The results of this research will provide greater understanding of the long-term consequences of not managing these invasions both in terms of fuel loads and soil nutrient conditions and in terms of whether native species will eventually recover in burned invaded sites under fire suppression. Lastly, results will provide site specific information regarding which native species and restoration treatments can be used in sites degraded by fire and grass invasion.

在过去的二十年里，科学家、土地管理者和公众已经认识到物种入侵的严重后果。尽管认识到这一点，但很少有研究记录了当入侵不受控制时入侵对生态系统的长期影响。拟议的研究评估了夏威夷季节性干燥林地中助火草的长期影响。这些草最初是作为牧草饲料引入的，后来逃到了荒地，促进了火灾的蔓延。这些地点的本地物种不适应火，导致本地物种急剧减少，养分循环发生强烈改变，包括氮（植物生长的关键资源）的损失。 拟议的研究利用观察和实验来评估入侵者引起的生态系统氮循环变化（在 20 世纪 90 年代有充分记录）自入侵以来如何随着时间的推移而发生变化，以及当前生长条件对本地物种的影响。实验将评估氮随时间的流失率、土壤碳库的变化以及这些变化对本地和非本地物种的影响。助火的非本地草是干旱和半干旱生态系统中一个重要的管理问题。这项研究的结果将有助于人们更好地了解不管理这些入侵所造成的长期后果，包括燃料负荷和土壤养分条件，以及本地物种是否最终会在灭火下被烧毁的入侵地点恢复。最后，结果将提供有关哪些本地物种和恢复处理可用于因火灾和草丛入侵而退化的地点的特定地点信息。