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A group of Colorado State University professors will spend the next five years evaluating – for the first time – how temperature and extreme weather such as floods and drought affect stream life differently in temperate and tropical climates.
In collaboration with Cornell University and the World Wildlife Fund, Colorado State biology Professor LeRoy Poff will lead a $3 million, five-year grant from the National Science Foundation as part of its Dimensions of Biodiversity initiative. Only 14 grants nationwide were awarded this month; CSU will split the grant with Cornell.
Researchers will study aquatic insects such as mayflies, caddisflies, and stoneflies and fish in streams along the Colorado Front Range – a temperate and seasonal climate – and insects, fish and amphibians in Ecuador, which has a tropical and stable climate. They will identify new species and barcode their DNA as well as track species movements based on such factors as their tolerance of warming water or declining oxygen levels at higher altitudes.
“We’re doing the science that really needs to be done to understand how species will respond to climate change – we need to know the physiological responses to thermal and oxygen stress much better,” Poff said. “This will be one of the first studies to look at sensitivity of species to both temperature and to environmental variation such as flooding and drought.
“If those conditions change, it’s going to have some effect on which species are able to do well and what loss of species might mean for entire food webs.”
Other CSU researchers working with Poff on the grant are Boris Kondratieff, a professor in the Department of Bioagricultural Sciences and Pest Management in the College of Agricultural Sciences, and Cameron Ghalambor, associate professor, and Chris Funk, assistant professor, both in the Department of Biology in the College of Natural Sciences.
Their hypothesis going into the research is that temperate species are likely to be less sensitive to climate change than those in the tropics because temperate streams are already subject to major swings in temperature and stream organisms often occupy a wide range of elevations. In the Colorado Rockies, for example, there’s a big change between summer and winter temperatures, both for streams at the base of the Rockies as well as those in the high alpine zone. Many species occur over a wide range of elevation, suggesting they could be tolerant of future climate warming.
In contrast, studying species diversity in the tropics is like taking apart layers of a cake: Temperature does not vary much seasonally, and as you move up in elevation you pass through stable layers of temperature each with unique species of aquatic insects, fish or frogs, Ghalambor said. Being restricted to a narrow range of elevation and temperature could therefore make tropical species more vulnerable to future changes in climate. In Ecuador, scientists will also look at amphibians in the glass frog family that often have a translucent belly. Many stream-dwelling amphibian species in the tropics are already declining and are the subject of international conservation efforts.
One way species will respond to climate change is by moving to higher elevations as temperatures warm. The research team will investigate the ability of species to accomplish that by examining the genetic structure of existing populations in streams at different elevations.
“If there’s not a lot of movement up or down in elevation within a species, you’ll see a genetic difference between populations,” Ghalambor said. “Using those genetic markers is a way of tracking species movement. The genetic similarity within the species can tell us how much individuals move between watersheds.”
Ultimately, the researchers intend to use this new information on species sensitivity to climate change and the ability of species to move with changing conditions as a basis for developing maps for policy makers and conservation groups to show how species are vulnerable to climate change in tropical and temperate streams.
The NSF grant will support several graduate students, but undergraduates are likely to be involved as well, Poff said.
Poff is a 2010 Professor Laureate in the College of Natural Sciences and director of CSU’s Graduate Degree Program in Ecology. His work focuses on basic and applied questions of how rivers function and on how to develop science-based criteria for managing these systems sustainably in the face of rapid global change. He has served on numerous National Research Council committees and science advisory boards. He is a recent elected president of an international professional society of river scientists and a Fellow of the Ecological Society of America’s Aldo Leopold Leadership Program.