SG: Synergistic effects of forest fragmentation and droughts on tropical plant demography

干旱对森林生态系统中的物种有许多负面影响，包括增加了种群减少甚至灭绝的风险。据推测，干旱对砍伐森林后残留的栖息地碎片中的种群的影响尤其严重。人们认为，生物多样性丰富的热带森林中的植物物种尤其如此，它们往往对环境条件的变化特别敏感。研究小组将使用在亚马逊中部收集的关于植物生长、繁殖和死亡的长期数据集来确定干旱如何影响热带雨林碎片中植物灭绝的风险。除了回答一个重要的悬而未决的生态问题外，这些结果还将帮助那些负责管理在生物、社会和经济上至关重要的森林生态系统的人，以应对预计干旱将变得更加频繁或严重的未来。在这样做的过程中，研究人员将对初出茅庐的科学家进行高级统计学和数学建模方面的培训，公开几个具有生态价值的数据集，并策划一个关于热带雨林及其对社会的全球重要性的艺术博物馆展览。为了确定干旱和森林砍伐如何相互作用，增加植物种群灭绝的风险，研究人员将使用之前收集的关于亚马逊中部一种植物物种数千个个体的生长、繁殖和死亡的数据：林下草本植物螺旋藻。这些数据是在巴西马瑙斯市附近未被破坏的热带雨林和经过实验隔离的森林碎片中收集的。研究人员将首先使用该地区40年的降雨量数据来确定干旱年份并对干旱强度进行分类。然后，他们将比较干旱前后植物的生长、繁殖和死亡率，以及干旱后多长时间可以检测到任何差异。最后，这些统计分析，连同干旱频率的分析，将被用来校准数学模型，它们将用来模拟亚马逊地区预测的替代干旱情景下的未来人口规模。这些模拟的结果将表明，在未被破坏的热带雨林或森林碎片中，人口因干旱而灭绝的可能性是否更大，以及当干旱更频繁或更严重时，这种可能性是否会发生变化。这一裁决反映了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。

Droughts have many negative effects on species in forest ecosystems, including increased risk of population decline and even extinction. It has been hypothesized that the effects of drought are especially severe for populations found in the fragments of habitat that remain following deforestation. This is thought to be especially true for plant species in biodiversity rich tropical forests, which are often especially sensitive to changes in environmental conditions. The research team will use a long-term dataset on plant growth, reproduction, and mortality collected in the Central Amazon to determine how droughts influence the risk of plant extinction in rain forest fragments. In addition to answering an important unresolved ecological question, the results will help those tasked with managing biologically, socially, and economically critical forest ecosystems for a future in which droughts are predicted to become more frequent or intense. In doing so the investigators will be training early-career scientists in advanced statistics and mathematical modeling, making several ecologically valuable datasets publicly available, and curating an art museum exhibit about rain forests and their global importance to society. To determine how droughts and deforestation interact to increase the risk that plant populations will go extinct, the researchers will use previously collected data on the growth, reproduction, and mortality of thousands of individuals of a plant species from the central Amazon: the understory herb Heliconia acmuniata. These data were collected in both unbroken rain forest and experimentally isolated forest fragments near the city of Manaus, Brazil. The researchers will first use four decades of data on rainfall in the region to identify drought years and categorize drought intensity. They will then compare plant growth, reproduction, and mortality before and after droughts, as well as how long after droughts any differences can be detected. Finally, these statistical analyses, along with the analysis of drought frequency, will be used to calibrate mathematical models with which they will simulate future population sizes under alternative drought scenarios predicted for the Amazon. The results of these simulations will indicate if the probability that populations will go extinct because of drought is greater in unbroken rain forest or forest fragments, and if this probability changes when droughts are more frequent or severe.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.