The story of Arctic greening has overlooked some main characters. At center stage are climate change and warming temperatures. Meanwhile, large grazing wildlife, such as caribou and muskoxen, also play a key role in the timing and abundance of Arctic plants, according to a study from the University of California, Davis.
in the journal PNAS Nexus, highlights the importance of large herbivores to the Arctic ecosystem, linking grazing with plant phenology and abundance in the Arctic tundra.
Phenology is the study of the timing and cyclical patterns in nature, such as when birds migrate, or when a plant first sprouts or blooms. Understanding such patterns is critically important in the Arctic, which is warming faster than anywhere on Earth.
鈥淐aribou and muskoxen play a key role in how soon plants emerge and this translates to how abundant they become,鈥 said lead author Eric Post, a professor and arctic ecologist in the 新澳门六合彩内幕信息 Davis Department of Wildlife, Fish and Conservation Biology. 鈥淭his is an important, and overlooked, factor we need to consider as we seek to more fully understand climate change impacts on tundra vegetation in the Arctic.鈥
Exclusion experiment
The research was conducted at a long-term study site near Kangerlussuaq, Greenland, where Post has been studying plant and animal interactions for 22 years. To understand how herbivores affect the timing of plant growth and abundance, the scientists excluded caribou and muskoxen from some study areas. From 2009 to 2017, they compared the timing of spring green-up of nine plant species with and without the grazing animals.
In general, plants where caribou or muskoxen were present experienced earlier green-up and greater abundance later in the growing season. About two-thirds of plants greened up earlier, and three-quarters were more abundant later in the season compared to plots without grazing. These include arctic draba and gray willow.
Some species, including dwarf birch and harebell, emerged later with grazers present. Dwarf birch was the only species studied that did not increase in abundance under grazing. In all cases, the presence or absence of large grazing wildlife influenced how the plants responded.
Grazing awareness
Post said it is not yet clear why the plants respond in this way, but it is important to understand that there is a connection.
鈥淲e鈥檙e used to thinking of the timing of plant availability as impacting the productivity of grazing animals, but not the reverse,鈥 Post said. 鈥淭he absence or presence of herbivores can also impact the timing of plant growth and their productivity.鈥
This is especially important considering that many caribou populations in the Arctic are in decline. Migratory tundra caribou (Rangifer tarandus) are listed as vulnerable by the I新澳门六合彩内幕信息N Red List and have lost more than half of their total abundance since the 1990s.
coauthored by Post and published Nov. 7, noted that supporting sustainable populations of herbivores in the Arctic could be a more effective nature-based solution to climate change in the region than planting trees there.
Co-authors for the PNAS Nexus study include 新澳门六合彩内幕信息 Davis alum Conor Higgins of the Yolo County Resource Conservation District, Pernille B酶ving of 新澳门六合彩内幕信息 Davis, Christian John of 新澳门六合彩内幕信息 Santa Barbara, Mason Post of the University of Washington, and Jeffrey Kerby of the Scott Polar Research Institute at Cambridge University. The authors give special thanks to the late Mads Forchhammer for his critical input and inspiring the study.
The study was funded by the U.S. National Science Foundation, National Geographic Society, European Union鈥檚 Horizon 2020 research program, and Aarhus University Research Foundation.
Media Resources
- Eric Post, 新澳门六合彩内幕信息 Davis Wildlife, Fish and Conservation Biology, epost@ucdavis.edu
- Kat Kerlin, 新澳门六合彩内幕信息 Davis News and Media Relations, 530-750-9195, kekerlin@ucdavis.edu
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