Knowledge Resource Center for Ecological Environment in Arid Area
DOI | 10.1111/1365-2745.12010 |
Tree effects on grass growth in savannas: competition, facilitation and the stress-gradient hypothesis | |
Dohn, Justin1; Dembele, Fadiala2; Karembe, Moussa3; Moustakas, Aristides4,5; Amevor, Kosiwa A.3; Hanan, Niall P.6 | |
通讯作者 | Dohn, Justin |
来源期刊 | JOURNAL OF ECOLOGY
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ISSN | 0022-0477 |
EISSN | 1365-2745 |
出版年 | 2013 |
卷号 | 101期号:1页码:202-209 |
英文摘要 | 1. The stress-gradient hypothesis (SGH) predicts an increasing importance of facilitative mechanisms relative to competition along gradients of increasing environmental stress. Although developed across a variety of ecosystems, the SGH’s relevance to the dynamic tree-grass systems of global savannas remains unclear. Here, we present a meta-analysis of empirical studies to explore emergent patterns of tree-grass relationships in global savannas in the context of the SGH. 2. We quantified the net effect of trees on understorey grass production relative to production away from tree canopies along a rainfall gradient in tropical and temperate savannas and compared these findings to the predictions of the SGH. We also analysed soil and plant nutrient concentrations in subcanopy and open-grassland areas to investigate the potential role of nutrients in determining grass production in the presence and absence of trees. 3. Our meta-analysis revealed a shift from net competitive to net facilitative effects of trees on subcanopy grass production with decreasing annual precipitation, consistent with the SGH. We also found a significant difference between sites from Africa and North America, suggesting differences in tree-grass interactions in the savannas of tropical and temperate regions. 4. Nutrient analyses indicate no change in nutrient ratios along the rainfall gradient, but consistent nutrient enrichment under tree canopies. 5. Synthesis. Our results help to resolve questions about the SGH in semi-arid systems, demonstrating that in mixed tree-grass systems, trees facilitate grass growth in drier regions and suppress grass growth in wetter regions. Relationships differ, however, between African and North American sites representing tropical and temperate bioclimates, respectively. The results of this meta-analysis advance our understanding of tree-grass interactions in savannas and contribute a valuable data set to the developing theory behind the SGH. |
英文关键词 | Africa competition facilitation North America plant-plant interactions rainfall gradient savanna stress-gradient hypothesis tree-grass interactions hypothesis |
类型 | Article |
语种 | 英语 |
国家 | USA ; Mali ; England |
收录类别 | SCI-E |
WOS记录号 | WOS:000317922200022 |
WOS关键词 | PLANT-PLANT INTERACTIONS ; RELATIVE IMPORTANCE ; ABIOTIC STRESS ; ENVIRONMENTS ; PRODUCTIVITY ; VEGETATION ; QUALITY ; AVAILABILITY ; METAANALYSIS ; COMMUNITIES |
WOS类目 | Plant Sciences ; Ecology |
WOS研究方向 | Plant Sciences ; Environmental Sciences & Ecology |
来源机构 | University of London ; Colorado State University |
资源类型 | 期刊论文 |
条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/178249 |
作者单位 | 1.Colorado State Univ, Nat Resource Ecol Lab, Dept 1499, Ft Collins, CO 80523 USA; 2.Inst Polytechn Rurale Format & Rech Appl IPR IFRA, Koulikouro, Mali; 3.Univ Bamako, Fac Sci & Tech, Bamako, Mali; 4.Univ London, Sch Biol & Chem Sci, London E1 4NS, England; 5.Univ Leeds, Inst Integrat & Comparat Biol, Fac Biol Sci, Leeds LS2 9JT, W Yorkshire, England; 6.S Dakota State Univ, Geog Informat Sci Ctr Excellence, Brookings, SD 57007 USA |
推荐引用方式 GB/T 7714 | Dohn, Justin,Dembele, Fadiala,Karembe, Moussa,et al. Tree effects on grass growth in savannas: competition, facilitation and the stress-gradient hypothesis[J]. University of London, Colorado State University,2013,101(1):202-209. |
APA | Dohn, Justin,Dembele, Fadiala,Karembe, Moussa,Moustakas, Aristides,Amevor, Kosiwa A.,&Hanan, Niall P..(2013).Tree effects on grass growth in savannas: competition, facilitation and the stress-gradient hypothesis.JOURNAL OF ECOLOGY,101(1),202-209. |
MLA | Dohn, Justin,et al."Tree effects on grass growth in savannas: competition, facilitation and the stress-gradient hypothesis".JOURNAL OF ECOLOGY 101.1(2013):202-209. |
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