Florida State University

College of Social Sciences & Public Policy

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NSF Grant Advances Geographer’s Research on Plant Ecosystems

Associate Professor of Geography Stephanie Pau at a key research site for her new project, Hawaii’s Laupahoehoe forest

Associate Professor of Geography Stephanie Pau has gained acclaim over the years for her investigations of plant species and their habitats, in part to determine the effects of climate. Now she has been awarded a National Science Foundation (NSF) research grant to extend the use of technology to advance her research.

This latest project will look at the relationship between leaf phenology and primary productivity in contrasting wet and dry tropical forest habitats, using geospatial data.

Leaf phenology is the term for the timing and amount of leaf production. Gross primary productivity represents the amount of carbon fixed by the forest from the atmosphere.

Tropical forests are one of the largest and most diverse biomes on Earth, yet estimates of gross primary productivity (GPP) – the largest flux of the carbon cycle – are not well understood from these regions. Leaf phenology in tropical forests can be highly variable because of climatic seasonality and a diversity of species, and it is unclear how these dynamics affect forest productivity. This project seeks to reconcile these two aspects and analyze how their relationship changes among species and with changes in climate.

The project’s broader societal benefit will be gaining a new understanding of climate change impacts on ecosystem functions in one of the most diverse and productive biomes on Earth, tropical forests.

In addition to tracking these forest dynamics across sites and seasons, the study will also advance the use of cutting edge technologies. Along with colleagues from the University of Florida and the U.S. Forest Service Pacific Southwest Forest and Range Experiment Station, Pau will fly a UAV (aka drone) to capture high-resolution imagery along the electromagnetic spectrum, from visible to shortwave infrared. Those measurements will be combined with satellite imagery and ground-based measures of the forest to help identify site-specific processes that underlie broad-scale geospatial patterns leading to more accurate interpretation of satellite observations.

The research will be conducted at two Hawaiian forest sites, the dry forest Palamanui and the wet forest Laupahoehoe, both on the state’s Big Island.

The nearly $330,000 NSF funding will also support integrating the research with education and citizen science by working with Hawaii’s highly successful program Teaching Change (TC) program, which provides outdoor, place-based, experiential education in ecology to middle and high school students. Through TC, a postdoctoral researcher will collaborate with middle and high school teachers to educate and train future spatial scientists, providing geospatial data for the proposed research while also meeting Next Generation Science Standards to help grow the data-capable workforce in the U.S.

These educational efforts will help to broaden participation in STEM by Pacific Islanders, an underrepresented minority in STEM fields; build teacher capacity for those in and outside of Hawaii; and provide career training for a postdoctoral researcher.

Pau is also a co-investigator on another project that was awarded more than $1 million by the NSF in January 2020, “Grassland Macroecology: A Lineage-based Framework.”

Human civilization depends on grasses for food, fuel and fiber. Grass-dominated ecosystems, such as grasslands and savannas, harbor tremendous biodiversity, are heavily impacted by humans, and are critical for regional and global carbon, water and energy cycling. The research will provide a synthesis of grass functional ecology that is critical for forecasting how grassy biomes will respond to increasing CO2, climate change and disturbance of the ecosystem.

To meet these challenges, Pau’s team will develop a novel integrative framework that reorganizes grass vegetation types around their evolutionary history, which should more accurately capture their functional diversity.

“We will collect an unprecedented suite of grass species’ functional traits capturing similarities and differences in ecophysiology, structure, life history, biogeochemistry and spectral reflectances, across several grassy ecosystems in the continental U.S.,” she explained. “This grant will allow us to develop and implement novel functional groupings to increase the accuracy of predictions.”

In May 2020, Pau and geography doctoral student Nicole Zampieri published a study in Scientific Reports on “The impact of Hurricane Michael on longleaf pine habitats in Florida.” The research found that at least 28% of the global total remaining extent of the longleaf pine ecosystem was affected in Florida alone.