MSB-ECA: Tropical biomes: how agriculture intensification and climate may alter fire regimes

森林和稀树草原是最大和多样化的生态系统。它们拥有一些最大的农业前沿。这些地区农业的迅速扩张导致了农产品的生产和出口，并向地球大气层释放了大量的碳。这些农业成就中的许多都是以高昂的环境成本为代价的：砍伐森林和植被退化。在未来几十年里，农业路线将决定森林和稀树草原的分布，以及它们是保持维持关键全球生态系统服务的能力，还是进入螺旋式下降的趋势，加速干扰，严重退化当地生态系统，造成全球后果。这项研究将量化随着农业集约化和环境变化，干扰机制可能发生的变化。这些假设是：(1)与正在进行的农业集约化相关的灭火将改变发生灾难性野火的可能性，以及(2)预计的气候变化可能导致更频繁、更高强度的火灾。项目成果可以为区域土地和火灾管理提供信息，特别是制定新的战略，以避免灾难性的野火，这些野火可能会破坏基础设施，对人类的健康和福祉产生负面影响，并向大气释放大量碳。这项提议将应用遥感图像、统计分析和数值模拟，以更清楚地了解全球范围内气候、土地利用和森林和稀树草原火灾制度之间在空间上的不同协同效应。它将评估烧毁面积和火灾频率如何随着环境变化和农业集约化而变化，以及灭火和未来环境变化可能如何改变发生大范围野火的可能性。通过遥感分析，该项目将促进对世界各地森林和稀树草原火灾干扰机制的了解，为在未来气候和土地利用变化下可能导致大规模生态系统变化的未量化门槛提供新的见解。要做到这一点，这项研究侧重于四个关键组成部分。首先，使用标准遥感产品(例如陆地卫星、MODIS)重建森林和稀树草原的火灾历史。第二，量化现有农业前沿土地利用过渡地图固有的不确定性。第三，建立火灾制度指标随土地利用变化、农业集约化和极端气候变化的统计模型。第四，改进空间显式火灾模型(FISC)，该模型将用于模拟火灾制度的潜在轨迹，并将适用于全球其他地区的森林稀树草原地区，在土地利用和环境变化的情况下。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Forests and savannas are largest and diverse ecosystems. They house some of the largest agricultural frontiers. The rapid expansion of agriculture in such regions is responsible for the production and export of agricultural commodities as well as releasing enormous amounts of carbon to Earth's atmosphere. Many of these agricultural achievements have come at a high environmental cost: deforestation and vegetation degradation. Over the next few decades, agricultural pathways will determine the distribution of forests and savannas and whether they retain the capacity to sustain key global ecosystem services or enter a downward spiral with accelerating disturbances that severely degrade native ecosystems, with global consequences. This study will quantify how disturbance regimes may shift as agriculture intensifies and the environment changes. The hypotheses are that (1) fire suppression associated with ongoing agricultural intensification will change the likelihood of catastrophic wildfires, and (2) projected changes in climate may results in more frequent, high-intensity fires. The project outcomes could inform regional land and fire management, particularly the development of new strategies to avoid catastrophic wildfires that can damage infrastructure; negatively impact human health and well-being; and release large amounts of carbon to the atmosphere.This proposal will apply remote sensing imagery, statistical analyses, and numerical modeling to build a clearer understanding of the spatially varying synergies between climate, land use, and fire regimes in forests and savannas at a global scale. It will evaluate how burned area and fire frequency change as a function of environmental change and agricultural intensification, as well as how fire suppression and future environmental changes may alter the probability of widespread wildfires. Through remote sensing analyses, this project will advance understanding of fire disturbance regimes in forests and savannas worldwide, providing new insights into the unquantified thresholds that may lead to large-scale ecosystem change under future climate and land-use changes. To do so, the study focuses on four key components. First, reconstructing fire histories in forests and savannas using standard remote sensing products (e.g. Landsat, MODIS). Second, quantifying uncertainties inherent to the existing maps of land-use transitions in the agricultural frontier. Third, building a statistical model of changes in fire regime metrics as a function of land-use change, agriculture intensification, and climatic extremes. Fourth, improving the spatially explicit fire model (FISC) that will be used to simulate potential trajectories of fire regimes, and will also be applicable to forest-savanna areas in the rest of the globe, under scenarios of land-use and environmental change.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.