新澳门六合彩内幕信息

Ozark Grasslands Experience Major Increase in Trees and Shrubs

What the Increase May Mean for the Future of Grasslands

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Wildflower on Missouri grassland
Glade grasslands are fire-adapted ecosystems that contain diverse plant communities. This glade in Missouri has been managed with prescribed fire and mechanical thinning of woody vegetation. Photo: Jesse Miller/新澳门六合彩内幕信息 Davis

Woody vegetation, such as trees and shrubs, has increased dramatically in Ozark grasslands over the past 75 years, according toin the journal Landscape Ecology.

The study examines grasslands called dolomite glades in the Mark Twain National Forest near Ava, Missouri. It analyzed historical aerial photos and found that woody vegetation cover increased from 8 percent in 1939 to 59 percent in 2014.

Fire was largely absent from this landscape between 1939 and 1984 and then was reintroduced within the past 30 years. The study shows that while prescribed fire has helped 鈥渉old the line鈥 against woody encroachment, it has not been able to reverse it. It added that the chances of reversing it are unlikely once woody plants cover more than 40 percent of the landscape. Meanwhile, unburned grassland areas have largely become densely wooded.

The future of grasslands

The study area is characteristic of a range of grassland and savanna ecosystems, and the findings raise questions about the future of grasslands: if, despite intensive management efforts, these ecosystems continue to favor woody vegetation, will it be possible to maintain open grasslands for the foreseeable future? 

timepoint comparison
This comparison of an Ozark glade landscape in 1939 and 2014 shows that tree cover has increased substantially. (Courtesy Jesse Miller) 

Grasslands represent a major component of biodiversity in the Ozarks. Most plants and animals in these habitats need open grasslands and won鈥檛 tolerate dense areas of trees and shrubs. 

Prescribed fire 鈥榚ssential鈥

鈥淲e show that prescribed fire is essential to the continued existence of these grasslands,鈥 said lead author Jesse Miller, who completed the research as a Ph.D. student at the University of Wisconsin-Madison. He is now a postdoctoral researcher at the University of California, Davis. 鈥淔ire was largely removed from the landscape for several decades. Now we better understand the ecological importance of fire for grasslands, and we鈥檙e still trying to reverse changes to grasslands that occurred during the period of fire exclusion.鈥

The study said that successful restorations require vigilant monitoring and management. The authors suggest that grassland restoration should not remove all woody plants, as some species, such as oaks, have been present historically. When possible, managers should prioritize maintaining existing grassland habitat and intervening before woody vegetation becomes so dense that it requires mechanical removal.

The research was supported by the National Science Foundation and the NSF Graduate Research Fellowship.

Media Resources

Kat Kerlin, 新澳门六合彩内幕信息 Davis News and Media Relations, 530-750-9195, kekerlin@ucdavis.edu

Jesse Miller, 新澳门六合彩内幕信息 Davis, jedmiller@ucdavis.edu

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