NSF Postdoc Fellowship in Biology FY 2017: Scaling up impacts of rainfall seasonality on tropical forest composition and function from herbarium collections and remote sensing data

这是一个NSF博士后研究奖学金在生物学，根据程序研究使用生物收集。这位名叫Naomi Schwartz的研究员正在进行研究并接受培训，以创新的方式利用生物收集，并由明尼苏达大学的Jennifer Powers指导。该研究员的研究探讨了季节性，特别是降雨的时间，如何影响植物在季节性干旱的热带森林中利用水分。有些干燥的森林经历一个非常多雨的雨季，然后是一个旱季，几乎没有降雨，而另一些森林则全年降雨量很低，但持续不断，还有一些森林有两个不同的旱季。降雨量的这些差异可能会影响植物利用水分和科普干旱的方式。例如，适应严重季节性干旱的物种可能对未来的干旱更具适应力。然而，我们仍然不知道季节性如何影响植物用水。这一点很重要，因为气候变化已经导致降雨季节性的变化和干旱的增加，我们无法预测这些变化将如何影响季节性干旱的热带森林。这位研究员正在使用来自拉丁美洲各地的植物标本集，这些标本集被用来测量与用水有关的植物特征，以及卫星图像，以观察季节性，光合作用和植物生长之间的联系。在更广泛的影响方面，该研究员正在培训学生使用植物标本集和卫星图像进行全球变化研究，并将她的结果纳入其他科学家可以使用的地球系统模型。了解季节性如何影响热带森林的组成和功能的一个关键挑战是收集必要的空间尺度数据，包括一系列的降雨系统。该研究员的研究通过使用植物标本收集和遥感的数据来解决这一挑战：两者都非常适合分析广泛的空间和时间尺度上的生态模式，但很少结合成一个综合的研究计划。该研究员正在测量与整个新热带地区四个植物标本馆的植物标本用水相关的性状，并利用这些测量结果来评估降雨季节性如何影响季节性干旱热带森林物种内和物种间的性状变异。她还利用遥感技术绘制树叶物候和生产力图，以评估它们如何受到降雨季节性的影响。很少有研究使用植物标本馆标本来研究一套与水力功能相关的性状，拟议的研究在证明使用植物标本馆标本进行植物功能生态学和全球变化研究的可行性方面做出了重大贡献。

This is an NSF Postdoctoral Research Fellowship in Biology, under the program Research Using Biological Collections. The fellow, Naomi Schwartz, is conducting research and receiving training that utilizes biological collections in innovative ways, and is being mentored by Jennifer Powers at the University of Minnesota. The fellow's research explores how seasonality, in particular the timing of rainfall, affects how plants use water in seasonally dry tropical forests. Some dry forests experience a very rainy, wet season followed by a dry season with virtually no rainfall, while other forests experience low, but constant, rainfall throughout the year, and still other forests have two distinct dry seasons. These differences in rainfall could affect the way plants use water and cope with drought. For example, species that are adapted to severe seasonal drought may be more resilient to future droughts. However, we still do not understand how seasonality affects plant water use. This is important, because climate change is already causing shifts in rainfall seasonality and increases in drought, and we cannot predict how these changes will affect seasonally dry tropical forests. The fellow is using herbarium collections from across Latin America, which are being used to measure plant characteristics related to water-use, as well as satellite imagery to observe links between seasonality, photosynthesis, and plant growth. In terms of broader impacts, the fellow is training students in using herbarium collections and satellite imagery for global change research, and incorporating her results into earth system models that other scientists can use.Because rainfall regimes vary temporally and over broad geographic scales, a key challenge to understanding how seasonality affects composition and function in tropical forests has been collecting data at the spatial scales necessary to encompass a range of rainfall regimes. The fellow's research addresses this challenge by using data from herbarium collections and remote sensing: both are uniquely suited to analyzing ecological patterns across broad spatial and temporal scales but are rarely combined into an integrated research program. The fellow is measuring traits related to water use on plant specimens at four herbaria throughout the Neotropics, and using these measurements to assess how rainfall seasonality affects trait variation within and across species in seasonally dry tropical forests. She is also using remote sensing to map leaf phenology and productivity, to assess how they are influenced by rainfall seasonality. Few studies have used herbarium specimens to examine a suite of traits related to hydraulic function, and the proposed research is making major contributions in terms of demonstrating the feasibility of using herbarium collections for study of plant functional ecology and global change.