Tag Archive for Helen Poulos

Poulos Authors 3 New Environmental-Themed Papers

Adjunct Assistant Professor of Environmental Studies Helen Poulos recently co-authored three new papers:

Wildfire and topography drive woody plant diversity in a Sky Island mountain range in the Southwest USA,” published in Ecology and Evolution on Oct. 5.

Choked out: Battling invasive giant cane along the Rio Grande/ Bravo Borderlands,” published in River Research and Applications on Sept. 20.

And “Mixed-severity wildfire as a driver of vegetation change in an Arizona Madrean Sky Island System, USA,” written alongside Michael Freiburger ’21 and published in Fire on Oct. 20.

Poulos’s research focuses on plant distribution patterns as a result of the influences of natural and anthropogenic disturbances on the levels of local, landscape, and regional. She also studies these patterns through plant ecophysiology, biogeochemistry, and community ecology.

Poulos Publishes Paper on Arizona Wildfires

Helen Poulos, adjunct assistant professor of environmental studies, is the lead author on a research article titled “Wildlife severity and vegetation recovery drive post-fire evapotranspiration in a southwestern pine-oak forest, Arizona, USA” published in Remote Sensing in Ecology and Conservation on May 8, 2021.
Undergraduates Michael Freiburger ’21 and Hunter Vannie ’20 assisted in collecting field data.

From the paper’s abstract:

In this study, post-fire ET was driven by plant species composition and tree canopy cover. ET was significantly higher in the morning and midday in densely vegetated post-fire shrublands than pine-dominated forests that remained 5–7 years after wildfire. Our results demonstrate that plant functional traits such as resprouting and desiccation tolerance drive post-fire ET patterns, and they are likely to continue to play critical roles in shaping post-fire plant communities and forest water cycling under future environmental change.

The paper is Poulos’ first result from her NASA ECOSTRESS project. She received a $300,000 grant from NASA in 2019 to study how high-severity wildfires in southern Arizona can permanently affect forests. The project uses data recorded by the ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) instrument on the International Space Station.

Study by Snashall ’21, Poulos Published in Forests

Gabe Snashall ’21 and Adjunct Assistant Professor of Environmental Studies Helen Poulos are the co-authors of “Oreos Versus Orangutans: The Need for Sustainability Transformations and Nonhierarchical Polycentric Governance in the Global Palm Oil Industry,” published in the Feb. 22 issue of Forests.

According to the paper’s abstract, “While the myriad benefits of palm oil as a food, makeup, and cleaning product additive drive its demand, globally, the palm oil industry remains largely unsustainable and unregulated. The negative externalities of palm oil production are diverse and devastating to tropical ecosystem integrity and human livelihoods in palm oil nations. Given the current trend in increasing sustainability and transparency in global supply chains, we suggest that sustainability policy reforms are feasible and have the potential to promote 21st-century U.S. and international sustainability standards. Polycentric governance may improve the attainment of sustainable global palm oil standards with a set of rules that interact across linear and nonlinear hierarchies and structures, thereby improving collaboration efforts, and increasing connectivity and learning across scales and cultures. Transformations towards sustainability in international palm oil governance has the potential to make valuable contributions to global sustainable development and improve the prosperity of poor rural communities in the tropics by providing a framework for achieving palm oil trade transparency and aligning the sustainability goals across a range of actors.”

Students Create Performances Based on Shadowing Physical Plant Employees

As part of the Introduction to Environmental Studies class, six students embedded themselves into the work lives of Wesleyan’s Physical Plant employees to learn the inner workings of campus.

Leila Henry ’23, Serena Aimen ’22, Tanvi Punja ’22, Molly Scotti ’22, Nina Criswell ’22, and Mikaela Marcotullio ’23 shadowed the Physical Plant workers for three-hour shifts every week throughout the fall semester. The experience concluded with performances on Dec. 5 that represented the culmination of that work.

The class was taught by Helen Poulos, adjunct assistant professor of environmental studies, and the performances were curated with the help of Allison Orr, creative director of Forklift Danceworks and the Distinguished Fellow in the College of the Environment.

The second-annual project grew out of BUILD (2016), a dance thesis performance choreographed by Clara Pinsky ’16.

Photos of the class presentations are below and on this Flickr album: (Photos by Laurie Kenney)

NASA Supports Poulos’s Wildfire Research

Helen

Helen Poulos examines a high fire severity site.

Wildfires can transform forest ecosystems to varying degrees, depending on fire severity. While low-severity wildfires change plant community composition by killing short-statured trees and understory plants, high-severity fires result in top kill of above-ground vegetation. This variation in wildfire effects can have major impacts on post-fire vegetation composition and water stress.

Helen Poulos, adjunct assistant professor of environmental studies, received a $300,000 grant from NASA on Dec. 5 to examine how forests can permanently change in response to high-severity wildfire in southeastern Arizona.

Poulos Studies Endangered Grass on Texas-Mexico Border

Pictured third from right, Helen Poulos, adjunct assistant professor of environmental studies, gathers with the “Fescue Rescue” team at Maderas del Carmen Protected Area in Mexico. There, the scientists are studying Guadalupe fescue, an endangered grass species.

field sites in the Sierra del Carmens, Coahila Mexico

Helen Poulos, adjunct assistant professor of environmental studies, works at a field site in the Sierra del Carmens, Coahuila Mexico. In September 2017, the U.S. government determined that Festuca ligulata needed protected species status and designated it a critical habitat under the Endangered Species Act of 1973.

The rare Guadalupe fescue once thrived in abundance atop mountains spanning the Texas-Mexico border, however, the desert-growing perennial grass is now so endangered, it only flourishes in two locations on Earth.

The rapid population decline is leaving scientists puzzled.

“Developing an effective recovery plan is essential for protecting Guadalupe fescue, however, the lack of basic information about this species’ ecology is a serious barrier to that goal,” explained Helen Poulos, adjunct assistant professor of environmental studies. “Urgent action is needed to stabilize the two extant populations.”

This summer, under Poulos’s leadership, Wesleyan received a National Park Service Grant to study Festuca ligulata through the Southwest Borderlands Resource Protection Program. She joined a bi-national team of scientists known as “Fescue Rescue” to research the two isolated fescue populations in Texas’s Big Bend National Park and the Maderas del Carmen Protected Area in Coahuila, Mexico.

Said Poulos, a plant ecologist who has worked at desert borderland sites for more than a decade, “The Guadalupe fescue has become so endangered that this has become a significant national and international conservation concern.”

Backed by the NPS grant, the Fescue Rescue team will conduct onsite visits from October to mid-November 2019 during Guadalupe fescue seed maturation. Seeds will be collected during this time and transported to labs at Sul Ross State University in Texas and Universidad Autónoma Antonio Narro in Mexico. At these locations, scientists will germinate the seeds and grow their own fescue refugial populations for multiple research purposes.

“Together, they’ll provide a springboard for future plant population genetics, enrichment planting, and adaptive management research on both sides of the border,” Poulos said. “Such information is vital for elaborating site-specific management plans for the species on both U.S. and Mexican soils.”

They’ll study environmental variables, inventory seed production, identify key factors that promote reproductive viability, and ultimately establish refugial populations on both sides of the border.

Although virtually nothing is known about the environmental influences on the growth and reproduction of Guadalupe fescue, Poulos believes the fescue’s population decline is a result of multiple factors.

“Environmental factors that have likely negatively influenced the fescue populations include a recent shift to a hotter and drier climate, the genetic and demographic consequences of small population sizes and isolation, trampling by humans and pack animals, trail runoff, competition from invasive species, and fungal infection of seeds,” she said.

In addition, naturally occurring wildfires, which play an important role in rejuvenating ecosystems, are rare due to livestock grazing in the early 1900s and subsequent direct fire suppression continuing to the present. The remaining plants in the two disjunct populations are likely highly inbred and lack genetic diversity. This can threaten the capacity of populations to resist pathogens and parasites, adapt to changing environmental conditions, and colonize new habitats.

Poulos hopes to deliver her final reports to the National Park Service by summer 2020.