The resilience of savanna ecosystems to changing fire regimes

本项目将调查火灾频率的变化如何影响热带和温带稀树草原生态系统中植被和土壤生物地球化学的结构和组成。这项工作的结果将解决自然生态系统如何应对地球仪迅速变化的火灾状况的问题。实地工作将在三个地点进行，这些地点的火灾频率已被实验性地控制了40年以上（南非、巴西和美国）。实地考察将描述植被群落的特征，以检验频繁的燃烧使植物群落对火越来越敏感的假设。实验室工作包括土壤取样和分析，将通过微生物活性测定和有机和无机化学测量来表征碳和营养物质的储存和周转。这些分析将被用来测试假设，火灾消耗生态系统的碳和抑制养分周转，抑制植被和微生物的恢复。

This project will investigate how changes in fire frequency have influenced the structure and composition of vegetation and soil biogeochemistry in both tropical and temperate savanna ecosystems. The results of this work will address the question of how natural ecosystems will respond to the rapidly changing fire regimes across the globe. Fieldwork will take place in three sites where fire frequency has been experimentally manipulated for >40 years (South Africa, Brazil, and the United States). The fieldwork will characterize the vegetation community to test the hypothesis that frequent burning shifts the plant community to being increasingly sensitive to fire. The labwork involves soil sampling and analysis, which will characterize the storage and turnover of carbon and nutrients via microbial activity assays and organic and inorganic chemistry measurements. These assays will be used to test the hypothesis that fire depletes ecosystem carbon and dampens nutrient turnover, inhibiting vegetation and microbial recovery.