Make Mine Dry

Watching endangered forests regrow, Jennifer Powers discovers clues to how plants, ecological processes and land use intertwine

When we think of tropical forests, most of us imagine tropical rainforests – lush Tarzan-vined, toucan-toting tangles of vegetation, exotic insects and other lurking creatures found in precipitation-rich places near the equator.

IonE resident fellow Jennifer Powers thinks of the “other” tropical forests—the ones that have trees that drop their leaves, endure periodic dry seasons and are among the most endangered ecosystems on Earth.

Tropical dry forests once made up four of every 10 acres of tropical forest worldwide. But over the past century these spectacular landscapes have been squeezed to nearly nothing under pressure from ax and plow. Now, thanks to valiant conservation efforts, they’re regrowing—creating rich opportunity to study not only how this unique ecosystem works, but also how nature heals.

Powers, an assistant professor in the College of Biological Sciences, is doing just that. “I work on the happy side of land use change,” she says. “[The forest] is coming back.”

Powers first became interested in complex ecosystems as a high school student in Italy, literally (and, yes, littorally) knee-deep in intertidal communities inhabiting the shores of the Adriatic Sea. When she started college in Oregon, she turned her attention to forest ecosystems. After working briefly in tropical rainforests, she encountered a tropical dry forest and, in her words, “fell in love.”

“Dry forests are such an important biome,” she says. “They’re just grossly understudied.”

Powers’ main focus is on understanding the interplay among the makeup of plant communities, human land use, and ecosystem function. How fast do demolished forests regrow? How diverse is the resulting mix of trees? How does the amount of carbon trapped in the soil change? Do rates differ across different soil types? Answers to questions like these yield important clues to how human activity affects the patterns and processes that contribute to healthy forest ecosystems and ultimately to the well-being of those who rely on them for food, clean water, carbon storage and other ecosystem services.

Tropical dry forests are particularly great systems for studying interactions, Powers says, because they have fewer kinds of plant species than tropical rainforests, yet a wide range of plant “functional traits”—strategies for dealing with the challenges the environment poses, such as dropping leaves during the dry season.

“It’s a huge amount of diversity, but it’s tractable,” she says. Not only that, it’s also pertinent: Climate change is expected to make tropical rainforests drier, so work like Powers’ will help us understand tomorrow’s warmer world.

Powers has conducted much of her tropical dry forest research in the Área de Conservación Guanacaste (ACG), a government-run conservation reserve and education center in northwestern Costa Rica. She chose that site, rather than an established international tropical research center, quite deliberately.

“I wanted to set up a long-term research program in a place where the results of studies could have a direct impact on conservation and management,” she says. “I didn’t want to be in a bubble.”

That commitment to being locally relevant recently led Powers and colleagues to create a nonprofit organization to help more closely connect research and on-the-ground information needs. With support from IonE, Powers held a workshop with ACG staff last summer to identify strategies to help research better inform park management, and vice versa.

“I hope other people can take the lessons we learned and implement them in their own way,” she says. “As ecologists, we just think if we do all this research and sit back it’s going to be used. [But] you can’t just publish your work and wait for it to be useful. …The burden is on us.”

Slide show: Changing Times

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Tropical dry forests once made up four of every 10 acres of tropical forest worldwide. Today, thanks to logging and farming, they are among Earth’s most endangered ecosystems. But in some places they are starting to grow back.

Jennifer Powers

Jennifer Powers

Editor’s note: Jennifer Powers was recently awarded a prestigious National Science Foundation Faculty Early Career Development (CAREER) grant to continue her work exploring the relationship between tropical dry forest carbon dynamics and plant traits, disturbance and environmental factors. The project will include developing and distributing educational materials on tropical dry forests to thousands of Costa Rican schoolchildren.

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More information on research at Área de Conservación Guanacaste