Experimental warming, not grazing, decreases rangeland quality on the Tibetan Plateau

NWIPB OpenIR

	Experimental warming, not grazing, decreases rangeland quality on the Tibetan Plateau
	Klein, Julia A.; Harte, John ; Zhao, Xin-Quan
	2007-03-01
发表期刊	ECOLOGICAL APPLICATIONS
卷号	17 期号:2 页码:541-557
文章类型	Article
摘要	We investigated experimental warming and simulated grazing ( clipping) effects on rangeland quality, as indicated by vegetation production and nutritive quality, in winter-grazed meadows and summer- grazed shrublands on the Tibetan Plateau, a rangeland system experiencing climatic and pastoral land use changes. Warming decreased total aboveground net primary productivity ( ANPP) by 40 g . m(-2) . yr(-1) at the meadow habitats and decreased palatable ANPP ( total ANPP minus non- palatable forb ANPP) by 10 g . m(-2) . yr(-1) at both habitats. The decreased production of the medicinal forb Gentiana straminea and the increased production of the non- palatable forb Stellera chamaejasme with warming also reduced rangeland quality. At the shrubland habitats, warming resulted in less digestible shrubs, whose foliage contains 25% digestible dry matter ( DDM), replacing more digestible graminoids, whose foliage contains 60% DDM. This shift from graminoids to shrubs not only results in lower- quality forage, but could also have important consequences for future domestic herd composition. Although warming extended the growing season in non- clipped plots, the reduced rangeland quality due to decreased vegetative production and nutritive quality will likely overwhelm the improved rangeland quality associated with an extended growing season.Grazing maintained or improved rangeland quality by increasing total ANPP by 20 - 40 g . m(-2) . yr(-1) with no effect on palatable ANPP. Grazing effects on forage nutritive quality, as measured by foliar nitrogen and carbon content and by shifts in plant group ANPP, resulted in improved forage quality. Grazing extended the growing season at both habitats, and it advanced the growing season at the meadows. Synergistic interactions between warming and grazing were present, such that grazing mediated the warming- induced declines in vegetation production and nutritive quality. Moreover, combined treatment effects were nonadditive, suggesting that we cannot predict the combined effect of global changes and human activities from single- factor studies.Our findings suggest that the rangelands on the Tibetan Plateau, and the pastoralists who depend on them, may be vulnerable to future climate changes. Grazing can mitigate the negative warming effects on rangeland quality. For example, grazing management may be an important tool to keep warming- induced shrub expansion in check. Moreover, flexible and opportunistic grazing management will be required in a warmer future.; We investigated experimental warming and simulated grazing ( clipping) effects on rangeland quality, as indicated by vegetation production and nutritive quality, in winter-grazed meadows and summer- grazed shrublands on the Tibetan Plateau, a rangeland system experiencing climatic and pastoral land use changes. Warming decreased total aboveground net primary productivity ( ANPP) by 40 g . m(-2) . yr(-1) at the meadow habitats and decreased palatable ANPP ( total ANPP minus non- palatable forb ANPP) by 10 g . m(-2) . yr(-1) at both habitats. The decreased production of the medicinal forb Gentiana straminea and the increased production of the non- palatable forb Stellera chamaejasme with warming also reduced rangeland quality. At the shrubland habitats, warming resulted in less digestible shrubs, whose foliage contains 25% digestible dry matter ( DDM), replacing more digestible graminoids, whose foliage contains 60% DDM. This shift from graminoids to shrubs not only results in lower- quality forage, but could also have important consequences for future domestic herd composition. Although warming extended the growing season in non- clipped plots, the reduced rangeland quality due to decreased vegetative production and nutritive quality will likely overwhelm the improved rangeland quality associated with an extended growing season.
关键词	Climate Warming Experimental Warming Forage Quality Global Change Grazing Pastoralism Productivity Rangelands Tibetan Plateau Tundra
WOS标题词	Science & Technology ; Life Sciences & Biomedicine
学科领域	生物科学
关键词[WOS]	SUMMER TEMPERATURE ; MEADOW ECOSYSTEM ; PLANT-RESPONSES ; CLIMATE-CHANGE ; ARCTIC TUNDRA ; ALPINE TUNDRA ; ICE CORES ; CARBON ; VEGETATION ; NITROGEN
收录类别	SCI
语种	英语
WOS研究方向	Environmental Sciences & Ecology
WOS类目	Ecology ; Environmental Sciences
WOS记录号	WOS:000245744200020
引用统计	被引频次：308[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://210.75.249.4/handle/363003/1283
专题	中国科学院西北高原生物研究所
作者单位	1.Univ Calif Berkeley, Dept Environm Sci Policy & Management, Div Ecosyst Sci, Berkeley, CA 94720 USA 2.Chinese Acad Sci, NW Plateau Inst Biol, Xining 810001, Qinghai, Peoples R China
推荐引用方式 GB/T 7714	Klein, Julia A.,Harte, John,Zhao, Xin-Quan. Experimental warming, not grazing, decreases rangeland quality on the Tibetan Plateau[J]. ECOLOGICAL APPLICATIONS,2007,17(2):541-557.
APA	Klein, Julia A.,Harte, John,&Zhao, Xin-Quan.(2007).Experimental warming, not grazing, decreases rangeland quality on the Tibetan Plateau.ECOLOGICAL APPLICATIONS,17(2),541-557.
MLA	Klein, Julia A.,et al."Experimental warming, not grazing, decreases rangeland quality on the Tibetan Plateau".ECOLOGICAL APPLICATIONS 17.2(2007):541-557.

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