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

Schwartz Naomi B, New York NY

Investigators

Abstract

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.