Effects of Drought Stress

Helen M. Regan

Helen M. Regan

Globally, forests of drier landscapes are being stressed by the drying effects of anthropogenic climate change, a research paper in the Proceedings of the National Academy of Sciences published the week of Feb. 29 reports.

“A warmer world is relatively drier as far as plants are concerned, and this stress can be more important than the direct effects of higher temperature,” said Helen M. Regan, a professor of biology, who is one of the coauthors on the paper.  “This drought stress can interact with fire regimes, insect outbreaks, and disease. Anticipating vegetation changes in a warming climate requires understanding interactions among these global change factors.”

The paper – “Global change and terrestrial plant community dynamics” – summarizes the state of the art in studies of global vegetation change and reviews recent research about the combined effects of climate change, land use, altered fire regimes and invasive species on the world’s forests and plant communities.

“Vegetation responses to land use and disturbance can be more immediate than to climate change, and can be long lasting,” Regan said.  Her coauthors on the paper are Janet Franklin (Arizona State University), Josep M. Serra-Diaz (Harvard University), and Alexandra D. Syphard (Conservation Biology Institute).

The researchers reviewed 150 studies spanning a range of biomes, techniques, disciplines, observational and experimental studies, including historical data spanning centuries, and paleo-environmental studies spanning millennia. They all point to highly dynamic terrestrial vegetation, responsive to climate and other global change factors.

“The media has given a lot of attention to climate change, drought, increased fires, disease, and habitat loss, but the effects of these agents of global change are not often discussed beyond their direct impact to humans,” Regan said. “Our paper highlights the impacts these threats have on forests and plant communities which process carbon, oxygen, water and nitrogen, and thus impact the earth’s oceans, atmosphere and climate and ultimately human beings.”

Regan performed part of the review focusing on models of “plant functional types” (a way of classifying plants according to similar life histories and responses to disturbance) and the effects of disturbance, land-use and climate change.

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