不同放牧强度对青藏高原东部高寒草甸植被和土壤影响的研究
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摘要
在草地生态系统中,放牧是主要生物干扰因素之一,显著影响草地植物群落的物种组成和生物多样性。因此,调查草地植物的放牧反应一直是草地生态学的中心议题。此外,放牧还显著改变土壤营养元素的含量和循环,尤其是碳、氮和磷的循环,从而进一步影响草地生态系统的诸多功能。大量的研究证明,放牧强度、放牧时间和放牧历史是决定放牧对草地生态系统影响的主要因素,其中放牧强度尤为重要。前期研究大多从二分法入手,仅仅进行了放牧和不放牧的比较,从而忽略了植被和土壤有可能存在的非线性放牧反应。而且已开展的研究大多都集中在温带地区,而在海拔高、气候寒冷、生态系统敏感和脆弱的青藏高原高寒草甸开展的研究较少。因此,从2005年到2007年,本研究根据地上植被残留量及参照前人对该地区放牧强度和演替阶段的划分,选取四个处理,分别为禁牧(GO)、轻牧(G1)、中牧(G2)和重牧(G3),对不同放牧强度下植被和土壤动态进行了三年系统监测和分析,可以说是对高寒地区放牧研究的重要补充,并且为青藏高原和的可持续利用和发展提供了较为全面的理论基础。
我们的研究结果表明：
1)整个实验过程中总共记录了17个科的69种植物,其中一年生植物占到9.7%,多年生植物为90.3%。禁牧监测到47种植物,而轻牧、中牧和重牧的物种数分别为56、54和31种。随着放牧强度的增加,地上植被盖度也随之下降,2007年降幅最大：从禁牧下的99.2±0.5%降到了重度放牧52.6±1.2%。同时,物种丰富度和个体密度受放牧强度的影响显著,随着放牧强度的增加其变化为非线性的单峰模式,即在中牧和轻牧下数值明显高于禁牧和重牧。这些结果证明,禁牧能显著提高植物的地表盖度,但适度的放牧有助于增加高寒草甸植物多样性。同时,考虑到高寒草甸承载放牧的功能,适当控制放牧强度是解决草场放牧利用和可持续发展等问题的有效管理措施。
2)基于植物功能特性水平上的RLQ分析结果显示,增强放牧强度线性增加低矮植物的相对丰富度,同时降低高植物相对丰富度；线性增加小种子植物,降低大种子植物；线性增加杂草生长型植物,降低禾草生长型植物；线性增加低度和中度适口植物,降低高适口植物；线性增加一年生植物,降低多年生植物；线性增加匍匐型植物,降低直立生长植物；线性增加莲座结构和具匍匐茎植物；降低丛生类植物。广义附加模型(GAM)分析显示非线性反应主要存在于莎草类、豆科类、不适口植物、克隆、非克隆和叶茎植物。以上结果显示,植物功能特性可以用来作为预示指标在一定程度上反应高寒草甸植物的放牧反应,但是在分析植物功能特性---放牧关系时应该考虑非线性反应。
3)基于植物种群水平上的典范相关分析(CCA)结果显示,21种常见植物种的放牧响应变化不一。其中随着放牧强度的增加,10种植物地表盖度线性降低；2种植物地表盖度线性增加；2种对轻度和中度的反应不显著,其盖度只在重度放牧下降低；其余7种呈现非线性反应,即在中牧下地表盖度最高。此外,种群水平上的分析还显示具有相同功能特性的植物种的放牧响应不一致,这说明单一的植物特性作为预测高寒草甸植物放牧反应的基础具有一定的局限性,而植物重要功能特性的交互作用在未来关于植被放牧响应的研究中需加以重视。
4)三年实验结果显示增加放牧强度导致0-15cm土壤中有机碳(SOC)的含量下降,最大降幅出现在2007年9月,从未放牧的57.6±6.1g/kg降低到了重度放牧的36.6±2.2g/kg。整个植物生长季中SOC存储量也随着放牧强度的增加而线性降低,且重度放牧造成SOC从土壤释放到空气中。另外,SOC的存储与地上植被残留量和地下根生物量密切正相关。这些结果表明,青藏高原高寒草甸生态系统中放牧通过降低植物生物量和抑制SOC存储,而重度放牧会导致青藏高原高寒草甸土壤从“碳库”到“碳源”的转变。
5)土壤全氮的含量也随着放牧强度的增大而逐渐降低,最大降幅出现在2005年5月,从未放牧的4.1±0.1g/kg降低到重度放牧的3.3±0.3g/kg。土壤全磷在放牧梯度上的变化趋势不清晰。随着放牧强度的增加,土壤中速效氮的含量显著增加,最大的增幅出现在2006年9月,从未放牧的14.9±1.2mg/kg增加到了重度放牧的36.4±1.2mg/kg。土壤速效磷沿放牧强度的变化与速效氮不同,相对未放牧,轻度和中度放牧增加土壤速效磷含量,重度放牧则降低土壤速效磷含量。
6)随着放牧强度的增加,60天原位培养累积矿化氮和硝化氮的含量逐渐增加。青藏高原东部放牧干扰下高寒草甸土壤氮矿化、硝化和土壤C/N呈现负相关关系(P<0.05),随着土壤C/N的增加,土壤中60天矿化氮和硝化氮含量均降低。从2005年到2007年,上述两种负相关关系均存在。我们结果显示,放牧增强土壤矿化和硝化作用,这一过程受到诸多因素调节,但是土壤C/N对土壤矿化和硝化作用具有显著的负影响。
In grassland ecosystem, grazing is one of the most important biotic disturbances, which influences the species composition and biodiversity. Therefore, exploring the response of vegetation to grazing has been identified as a critical research area in grassland ecology. Further-more, grazing significantly changes the content and cycle of soil nutrient, especially carbon, nitrogen and phosphorus, which in turn affects the fuction of grassland ecosystem. Many studies have proved that grazing intensity, time and history are important factors that determine how grazing changes grassland communities, especially grazing intensity. A large number of previous studies used only paired sites (grazed vs. ungrazed), and ignored the effects of different grazing levels. This may have concealed nonlinear responses of plants to increased grazing. Moreover, many studies on the effects of grazing intensity have focused on temperate ecosystems, but there is little information on alpine meadow on Qinghai-Tibetan plateau with the high altitude, cold, and sensitive ecosystems. Therefore, according the residual biomass and earlier studies, our research chose no grazing (GO), light grazing (G1), moderate grazing (G2) and heavy grazing (G3), aimed to investigate the vegetation and soil dymatics under different grazing intensity from2005to2007, which not only complements previous studies on the effects of grazing in alpine area, but can also provide a theoretical framework for the utilization and development of Qinghai-Tibetan plateau.
Our study suggest that
1). During the experimental period, a total of69species belonging to17families were recorded. Apart from the47plant species occurring in no grazing (GO),9and7new species were observed in light (G1) and moderate grazing (G2), respectively. In heavy grazing (G3),31species were observed. Grazing intensity also negatively affected the total ground cover of plant community. The most pronounced decrease occurred in the third year (2007), when ground cover ranged from99.2±0.5%in GO to52.6±1.2%in G3. Simultaneously, grazing intensity significantly influenced species richness and plant density, which indicated a unimodal response of species richness along the grazing gradients, i.e. a higher species richness and plant density in light and moderate grazing than in none and heavy grazing. These results proved that fencing is an effective way to improve ground cover; however, moderate grazing can help to increase biodiversity of alpine meadow. With the consideration of grazing function, moderate grazing is the solution to resolve the dilemma between sustainable livestock production and development and maintenance of pastoral ecosystems.
2). RLQ analysis, based on plant functional traits showed that, increased grazing led to a linear increase of short plants over tall plants, light seeded plants over heavy seeded plants, forbs over grasses, low and medium palatable plants over high palatable plants, annuals over perennials, prostrate over erect plants, rosette and stoloniferous plants over tussock plants. GAM analysis showed that non-linear responses were found in sedges, legumes, unpalatable, clonal, unlonal and leafy stem plants. These results showed that plant functional traits can be used to predicate the grazing response of vegetation composition and that non-linearity should be considered when analyzing functional trait-grazing relationships.
3).Canonical correspondence analysis, based on species level showed that the21commone species responded differently to grazing intensity. Specifically, With increasing grazing disturbance, ten species showed reduced ground cover and two species increased ground cover; two species did not show obvious differences among fencing, light and moderate grazing, but significant decrease in heavy grazing; seven species indicated non-linear influences that increased at light and moderate, but decreased at heavy grazing. Analysis based on species levels also showed that species with same single traits exhibited different responses to grazing, which implys that the predictions solely based on single traits would give misleading results for vegetation changes under pasture management. A more thorough functional analysis of the combination of key traits is needed in future studies on the responses of vegetation to grazing.
4). The results of three-year study showed that grazing intensity decrease the SOC content of0-15cm soil. The highest decrease occurred in September2007, from57.6±6.1g/kg in no-grazing to36.6±2.2g/kg in heavy grazing intensity. Furthermore, soil organic carbon storage during the plant growing seasons was also significantly reduced by grazing intensity, and heavy grazing caused SOC emission from soil to atmosphere. SOC storage was closely positively related to both aboveground residues and belowground biomass. These results indicates that a grazing-induced reduction in plant biomass productivity and changes in species composition would depress soil carbon storage, and that an increase in grazing pressure can lead to a gradual change of alpine meadow soils from being'carbon sinks'to become'carbon sources'.
5). Total nitrogen in the soil was found to decrease with increasing grazing intensity. The highest decrease occurred in May2005, from4.1±0.1g/kg in ungrazed areas to3.3±0.3g/kg in heavily grazed areas. The response of total phosphorus in the soil to grazing was not clear. Soil available nitrogen rose significantly as grazing intensity went up. The highest increase occurred in September2006, from14.9±1.2mg/kg in ungrazed plots to36.4±1.2mg/kg in heavily grazed plots. Different from the response of soil available nitrogen to grazing, both light and moderate grazing increased soil available phosphorus relative to nongrazing, whereas the opposite was true for heavy grazing.
6). Cumulative nitrogen mineralized during a60-day period of in situ cultivation increasely progressively with increasing grazing intensity, The cumulative nitrate nitrogen showed a similar response. Nitrogen mineralization and nitrification in alpine meadow of Eastern Qinghai-Tibetan Plateau was negatively related to soil C/N ratio, that is, both mineralized nitrogen and nitrate nitrogen decreased with increasing soil C/N raio. This negative relationship between mineralized nitrogen or nitrate nitrogen and C/N ratio was observed in both2005and2007. Our results show that soil nitrogen mineralization and nitrification are promoted by grazing but negatively affected by soil C/N ratio.
我们的研究结果表明：
1)整个实验过程中总共记录了17个科的69种植物,其中一年生植物占到9.7%,多年生植物为90.3%。禁牧监测到47种植物,而轻牧、中牧和重牧的物种数分别为56、54和31种。随着放牧强度的增加,地上植被盖度也随之下降,2007年降幅最大：从禁牧下的99.2±0.5%降到了重度放牧52.6±1.2%。同时,物种丰富度和个体密度受放牧强度的影响显著,随着放牧强度的增加其变化为非线性的单峰模式,即在中牧和轻牧下数值明显高于禁牧和重牧。这些结果证明,禁牧能显著提高植物的地表盖度,但适度的放牧有助于增加高寒草甸植物多样性。同时,考虑到高寒草甸承载放牧的功能,适当控制放牧强度是解决草场放牧利用和可持续发展等问题的有效管理措施。
2)基于植物功能特性水平上的RLQ分析结果显示,增强放牧强度线性增加低矮植物的相对丰富度,同时降低高植物相对丰富度；线性增加小种子植物,降低大种子植物；线性增加杂草生长型植物,降低禾草生长型植物；线性增加低度和中度适口植物,降低高适口植物；线性增加一年生植物,降低多年生植物；线性增加匍匐型植物,降低直立生长植物；线性增加莲座结构和具匍匐茎植物；降低丛生类植物。广义附加模型(GAM)分析显示非线性反应主要存在于莎草类、豆科类、不适口植物、克隆、非克隆和叶茎植物。以上结果显示,植物功能特性可以用来作为预示指标在一定程度上反应高寒草甸植物的放牧反应,但是在分析植物功能特性---放牧关系时应该考虑非线性反应。
3)基于植物种群水平上的典范相关分析(CCA)结果显示,21种常见植物种的放牧响应变化不一。其中随着放牧强度的增加,10种植物地表盖度线性降低；2种植物地表盖度线性增加；2种对轻度和中度的反应不显著,其盖度只在重度放牧下降低；其余7种呈现非线性反应,即在中牧下地表盖度最高。此外,种群水平上的分析还显示具有相同功能特性的植物种的放牧响应不一致,这说明单一的植物特性作为预测高寒草甸植物放牧反应的基础具有一定的局限性,而植物重要功能特性的交互作用在未来关于植被放牧响应的研究中需加以重视。
4)三年实验结果显示增加放牧强度导致0-15cm土壤中有机碳(SOC)的含量下降,最大降幅出现在2007年9月,从未放牧的57.6±6.1g/kg降低到了重度放牧的36.6±2.2g/kg。整个植物生长季中SOC存储量也随着放牧强度的增加而线性降低,且重度放牧造成SOC从土壤释放到空气中。另外,SOC的存储与地上植被残留量和地下根生物量密切正相关。这些结果表明,青藏高原高寒草甸生态系统中放牧通过降低植物生物量和抑制SOC存储,而重度放牧会导致青藏高原高寒草甸土壤从“碳库”到“碳源”的转变。
5)土壤全氮的含量也随着放牧强度的增大而逐渐降低,最大降幅出现在2005年5月,从未放牧的4.1±0.1g/kg降低到重度放牧的3.3±0.3g/kg。土壤全磷在放牧梯度上的变化趋势不清晰。随着放牧强度的增加,土壤中速效氮的含量显著增加,最大的增幅出现在2006年9月,从未放牧的14.9±1.2mg/kg增加到了重度放牧的36.4±1.2mg/kg。土壤速效磷沿放牧强度的变化与速效氮不同,相对未放牧,轻度和中度放牧增加土壤速效磷含量,重度放牧则降低土壤速效磷含量。
6)随着放牧强度的增加,60天原位培养累积矿化氮和硝化氮的含量逐渐增加。青藏高原东部放牧干扰下高寒草甸土壤氮矿化、硝化和土壤C/N呈现负相关关系(P<0.05),随着土壤C/N的增加,土壤中60天矿化氮和硝化氮含量均降低。从2005年到2007年,上述两种负相关关系均存在。我们结果显示,放牧增强土壤矿化和硝化作用,这一过程受到诸多因素调节,但是土壤C/N对土壤矿化和硝化作用具有显著的负影响。
In grassland ecosystem, grazing is one of the most important biotic disturbances, which influences the species composition and biodiversity. Therefore, exploring the response of vegetation to grazing has been identified as a critical research area in grassland ecology. Further-more, grazing significantly changes the content and cycle of soil nutrient, especially carbon, nitrogen and phosphorus, which in turn affects the fuction of grassland ecosystem. Many studies have proved that grazing intensity, time and history are important factors that determine how grazing changes grassland communities, especially grazing intensity. A large number of previous studies used only paired sites (grazed vs. ungrazed), and ignored the effects of different grazing levels. This may have concealed nonlinear responses of plants to increased grazing. Moreover, many studies on the effects of grazing intensity have focused on temperate ecosystems, but there is little information on alpine meadow on Qinghai-Tibetan plateau with the high altitude, cold, and sensitive ecosystems. Therefore, according the residual biomass and earlier studies, our research chose no grazing (GO), light grazing (G1), moderate grazing (G2) and heavy grazing (G3), aimed to investigate the vegetation and soil dymatics under different grazing intensity from2005to2007, which not only complements previous studies on the effects of grazing in alpine area, but can also provide a theoretical framework for the utilization and development of Qinghai-Tibetan plateau.
Our study suggest that
1). During the experimental period, a total of69species belonging to17families were recorded. Apart from the47plant species occurring in no grazing (GO),9and7new species were observed in light (G1) and moderate grazing (G2), respectively. In heavy grazing (G3),31species were observed. Grazing intensity also negatively affected the total ground cover of plant community. The most pronounced decrease occurred in the third year (2007), when ground cover ranged from99.2±0.5%in GO to52.6±1.2%in G3. Simultaneously, grazing intensity significantly influenced species richness and plant density, which indicated a unimodal response of species richness along the grazing gradients, i.e. a higher species richness and plant density in light and moderate grazing than in none and heavy grazing. These results proved that fencing is an effective way to improve ground cover; however, moderate grazing can help to increase biodiversity of alpine meadow. With the consideration of grazing function, moderate grazing is the solution to resolve the dilemma between sustainable livestock production and development and maintenance of pastoral ecosystems.
2). RLQ analysis, based on plant functional traits showed that, increased grazing led to a linear increase of short plants over tall plants, light seeded plants over heavy seeded plants, forbs over grasses, low and medium palatable plants over high palatable plants, annuals over perennials, prostrate over erect plants, rosette and stoloniferous plants over tussock plants. GAM analysis showed that non-linear responses were found in sedges, legumes, unpalatable, clonal, unlonal and leafy stem plants. These results showed that plant functional traits can be used to predicate the grazing response of vegetation composition and that non-linearity should be considered when analyzing functional trait-grazing relationships.
3).Canonical correspondence analysis, based on species level showed that the21commone species responded differently to grazing intensity. Specifically, With increasing grazing disturbance, ten species showed reduced ground cover and two species increased ground cover; two species did not show obvious differences among fencing, light and moderate grazing, but significant decrease in heavy grazing; seven species indicated non-linear influences that increased at light and moderate, but decreased at heavy grazing. Analysis based on species levels also showed that species with same single traits exhibited different responses to grazing, which implys that the predictions solely based on single traits would give misleading results for vegetation changes under pasture management. A more thorough functional analysis of the combination of key traits is needed in future studies on the responses of vegetation to grazing.
4). The results of three-year study showed that grazing intensity decrease the SOC content of0-15cm soil. The highest decrease occurred in September2007, from57.6±6.1g/kg in no-grazing to36.6±2.2g/kg in heavy grazing intensity. Furthermore, soil organic carbon storage during the plant growing seasons was also significantly reduced by grazing intensity, and heavy grazing caused SOC emission from soil to atmosphere. SOC storage was closely positively related to both aboveground residues and belowground biomass. These results indicates that a grazing-induced reduction in plant biomass productivity and changes in species composition would depress soil carbon storage, and that an increase in grazing pressure can lead to a gradual change of alpine meadow soils from being'carbon sinks'to become'carbon sources'.
5). Total nitrogen in the soil was found to decrease with increasing grazing intensity. The highest decrease occurred in May2005, from4.1±0.1g/kg in ungrazed areas to3.3±0.3g/kg in heavily grazed areas. The response of total phosphorus in the soil to grazing was not clear. Soil available nitrogen rose significantly as grazing intensity went up. The highest increase occurred in September2006, from14.9±1.2mg/kg in ungrazed plots to36.4±1.2mg/kg in heavily grazed plots. Different from the response of soil available nitrogen to grazing, both light and moderate grazing increased soil available phosphorus relative to nongrazing, whereas the opposite was true for heavy grazing.
6). Cumulative nitrogen mineralized during a60-day period of in situ cultivation increasely progressively with increasing grazing intensity, The cumulative nitrate nitrogen showed a similar response. Nitrogen mineralization and nitrification in alpine meadow of Eastern Qinghai-Tibetan Plateau was negatively related to soil C/N ratio, that is, both mineralized nitrogen and nitrate nitrogen decreased with increasing soil C/N raio. This negative relationship between mineralized nitrogen or nitrate nitrogen and C/N ratio was observed in both2005and2007. Our results show that soil nitrogen mineralization and nitrification are promoted by grazing but negatively affected by soil C/N ratio.
引文
[1]Aarssen, L.W., Jordan, C.Y. Between-species patterns of covariation in plant size, seed size and fecundity in monocarpic herbs. Ecoscience.2001,8:471-477.
[2]Abril, A., Bucher, E.H. The effects of overg razing on soil microbial community and fertility in the Chaco dry savannas o f Argentina. Applied Soil Ecology.1999,12:159-167.
[3]Anderson, M.T., Ritchie, M.E., McNaughton, S.J. Rainfall and soils modify plant community response to grazing in Serengeti national park. Ecology.2007,88:1191-1201.
[4]Arnold, J.F. Plant life-form classification and its use in evaluating range conditions and trend. Journal of Range Management.1955,8:176-181.
[5]Augner, M., Tuomi, J., Rout, M. Effects of defoliation on competitive interactions in European white birch. Ecology.1997,78:2369-2377.
[6]Augustine, D.J., McNaughton, S.J. Ungulate effects of the functional species composition of plant communities:herbivore selectivity and plant tolerance. Journal of Wildlife Management.1998,62:1165-1183.
[7]Bardgett, R.D., Wardle, D.A. Herbivore-mediated linkages between aboveground and belowground communities. Ecology.2003,84:2258-2268.
[8]Barger, N.N., Ojima, D.S., Belnap, J., Wang, S.P., Wang, Y.F., Chen, Z.Z. Changes in plant functional groups, litter quality, and soil carbon and nitrogen mineralization with sheep grazing in an inner Mongolian grassland. Journal of Range Management.2004, 57:613-619.
[9]Baron, V.S., Mapfumo, E., Dick, A.C., Naeth, M.A., Okine, E.K., Chanasyk, D.S. Grazing intensity impacts on pasture carbon and nitrogen flow. Journal of Range Management.2002,55:535-541.
[10]Bauer, A., Cote, C.V., Blank, A.L. Soil property comparison in virgin grass lands between grazed and non-grazed management systems. Soil Science Society of American Journal. 1987,51:176-182.
[11]Belsky, A.J. Does herbivore benefit plants? A review of the evidence. The American Naturalist.1986,127:871-891.
[12]Bergelson, J., Juenger, T, Crawley, M.J. Regrowth following herbivory in Ipomopsis aggregata:compensation but not overcompensation. The American Naturalist.1996, 148:744-755.
[13]Bowman, R.A., Cole, C.V. An exploratory method for fractionation of organic phosphorus from grassland soil. Soil Science.1978,125:95-101.
[14]Bullock, J.M., Franklin, J., Stevenson, M.J., Silvertown, J., et al. A plant trait analysis of responses to grazing in a long-term experiment. Journal of Applied Ecology.2001,38: 253-267.
[15]Cao, GM, Tang, Y.H., Mo, W.H., Wang, Y.S., Li, Y.N., Zhao, X.Q. Grazing intensity alters soil respiration in an alpine meadow on the Tibetan plateau. Soil Biology and Biochemistry. 2004,36:237-243.
[16]Chaneton, E. J., Lemcoff, J.H., Lavado, R.S. Nitrogen and phosphorus cycling in grazed and ungrazed plots in a temperate subhumid grass land in Argentina. Applied Ecology.1996, 33:291-302.
[17]Chen, D.D., Zhang, S.H., Dong, S.K., Wang, X.T., Du, G.Z.. Effect of land-use on soil nutrients and microbial biomass of an alpine regiona on the northeatern Tibetan Plateau, China. Land Degradation and Development.2010,21(5):446-452.
[18]Cingolani, A.M., Posse, G., Collantes, M.B. Plant functional traits, herbivore selectivity and response to sheep grazing in Patagonian steppe grasslands. Journal of Applied Ecology. 2005a,42:50-59.
[19]Cingolani, A.M., Noy-Meir, I., Diaz, S. Grazing effects on rangeland diversity:a synthesis of contemporary models. Ecological Application.2005b,15:757-773.
[20]Conant, R.T., Paustian, K., Elliott, E.T., Grassland management and conversion into grassland: effects on soil carbon. Applied Ecology.2011,11:343-355.
[21]Cosyns, E., Delporte, A., Lens, L., Hoffmann, M. Germination success of temperate grassland species after passage through ungulate and rabbit guts. Journal of Ecology.2005, 93:353-361.
[22]Coley, P.D., Bryant, J.P., Chapin, F.S. Resource availability and plant anti-herbivore defense. Science.1985,230:895-899.
[23]Connell, J. H. Diversity in tropical rain forests and coral reefs. Science.1978, 199:1302-1310.
[24]Cui, X.Y., Wang, Y.F., Niu, H.S., Wu, J., Wang, S.P., Schnug, E., Rogasik, J., Fleckenstein, J., Tang, Y.H. Effect of long-term grazing on soil organic carbon content in semiarid steppes in Inner Mongolia. Ecological Research.2005,20:519-527.
[25]Dahlgren, R.A., Singer, M.J., Huang, X. Oak tree and grazing impacts on soil properties and nutrients in California oak woodland. Biochemistry.1997,39:45-64.
[26]Danell, K., Bergstrom, R., Edenius, L., Ericsson, G. Ungulates as drivers of tree population dynamics at module and genet levels. Forest Ecology and Management.2003,181:67-76.
[27]Danell, K., Hjalten, J., Ericson, L., Elmqvist, T. Vole feeding on male and female willow shoots along a gradient of plant productivity. Oikos.1991,62:145-152.
[28]De Bello, F., Leps, J.A.N., Sebastia, M.T. Predictive value of plant traits to grazing along a climatic gradient in the Mediterranean. Journal of Applied Ecology.2005.42:824-833.
[29]De Deyn, G.B., Cornelissen, J.H.C., Bardgett, R.D. Plant functional traits and soil carbon sequestration in contrasting biomes. Ecology Letters.2008,11:516-531.
[30]Derner, J.D., Briske, D.D., Boutton, T.W. Does grazing mediate soil carbon and nitrogen accumulation beneath C4 perennial grasses along an environmental gradient? Plant and Soil.1997,191:147-156.
[31]Diaz, S., Lavorel, S., McIntyer, S. et al. Plant trait responses to grazing-a global synthesis. Global Change Biology.2007,13:313-341.
[32]Dray, S., Dufour, A.B., Chessel, D. The ade4-package:two-table and K-table methods. R News.2007,7:47-52.
[33]Doledec, S., Chessel, D., ter Braak, C. J. F., et al. Matching species traits to environmental variables:a new three-table ordination method. Environment Ecology Statistics.1996, 3:143-166.
[34]Dyksterhuis, E.J. Condition and management of rangelands based on quantitative ecology. Journal of Range Management.1949,2:104-115.
[35]Eviner, V. T., Chapin, F. S. Functional matrix:A conceptual framework for predicting multiple plant effects on ecosystem processes. Annual Review of Ecology and Systematics. 2003,34:455-485.
[36]Evju, M., Austrheim, G., Halvorsen, R., Mysterud, A. Grazing responses in herbs in relation to herbivore selectivity and plant traits in an alpine ecosystem. Oecologia.2009,161: 77-85.
[37]Ferris, J. C. Growth and nitrogen mineralization of selected fungi and fungal-feeding nematodes on sand amended with organic matter. Plant and Soil.2000,218:91-101.
[38]Friesen, D.K., Blair, GJ. A dual radiotracer study of transformations of organic, inorganic and plant residue phosphorus in soil in the presence and absence of plants. Australian Journal of Soil Research.1988,26:355-366.
[39]Frank, D.A. Groffman, P.M. Ungulate vs. landscape control of soil C and Nprocesses in grasslands of Yellowstone National Park. Ecology.1998,79:2229-2241.
[40]Frank, A.B., Tanaka, D.L., Hofmann, L., et al. Soil carbon and nitrogen of Northern Great Plains grasslands as influenced by long-term grazing. Journal of Range Management.1995, 48(5):470-474.
[41]Gao, Y.H., Luo, P., Wu, N., Yi, S.L., Chen, H. Biomass and nitrogen response to grazing intensity in an alpine meadow on the Eastern Tibetan Plateau. Polish Journal of Ecology. 2007,53,469-479.
[42]Gao, Y.H., Luo, P., Wu, N., Chen, H., Wang, G.X. Impacts of grazing intensity on nitrogen pools and nitrogen cycle in an alpine meadow on the eastern Qinghai-Tibetan Plateau. Applied Ecology and Environment Research.2008,6:69-79.
[43]Gao, Y.H., Schumann, M., Chen, H., Wu, N., Luo, P. Impacts of grazing intensity on soil carbon and nitrogen in an alpine meadow on the eastern Tibetan Plateau. Journal of Food, Agriculture and Environment.2009,7:749-754.
[44]Gibson, D.J. Grasses and grassland ecology. Oxford University Press Inc., New York.2009.
[45]Gifford, G.F., Hawkins, R.H. Hydrologic impact of grazing on infiltration:acritical review. Water Resource Research.1978,14:305-313.
[46]Grayston, S.J., Vaughan, D., Jones, D. Rhizosphere carbon flow in trees, in comparison with annual plants:the importance of root exudation and its impact on microbial activity and nutrient availability. Applied Soil Ecology.1996,5:29-56.
[47]Greene, R.S.B., Kinnell, P.I.A., Wood, J.T. Role of plant cover and stock tramp ling on runoff and soil erosion from semiarid wooded rangelands. Australian Journal of Soil Research. 1994,32:953-973.
[48]Guerif, J. Factors influencing compaction induced increases in soil strength. Soil& Tillage Research.1990,16:167-178.
[49]Grime, J.P. Plant strategies and vegetation processes. Wiley, Chichester.1999.
[50]Grime, J.P. Plant Strategies, Vegetation Processes, and Ecosystem Properties,2nd edn. John Wiley and Sons, Chichester.2001.
[51]Grime, J.P., Cornelissen, J.H.C., Thompson, K., Hodgson, J.G. Evidence of a causal connection between anti-herbivore defense and the decomposition rate of leaves. Oikos. 1996,77:489-494.
[52]Grubb, P. A positive distrust in simplicity. Journal of Ecology.1992,80:585-610.
[53]Han, G.D., Hao, X.Y., Zhao, M.L, et al. Effect of grazing intensity on carbon and nitrogen in soil and vegetation in a meadow steppe in Inner Mongolia. Agriculture, Ecosystems & Environment.2008,125:21-32.
[54]Han, W.W., Luo, Y.J., Du, G.Z. Effects of clipping on diversity and above-ground biomass associated with soil fertility on an alpine meadow in the eastern region of the Qinghai-Tibetan Plateau. New Zealand Journal of Agricultural Research.2007, 50:361-368.
[55]Hastie, T.J., Tibshirani, R.J. Generalized additive models. Chapman and Hall, London.1990.
[56]Hassink, J.,Bouwman,L. A.,Zwart,K. B., et al. Relationships between habitable pore space, soil biota and mineralization rates in grassland soils. Soil Biology & Biochemistry.1993, 25:47-55.
[57]Haynes, R.J., Williams, P.H. Nutrient cycling and soil fertility in the grazed pasture ecosystem. Advances in Agronomy.1993,49:119-199.
[58]Hejduk, S., Hrabe, F. Influence of different systems of grazing, type of swards and fertilizing on underground phytomass of pastures. Plant, Soil and Environment.2003,49:18-23.
[59]Hendricks, H.H., Bond, W.J., Midgley, J.J., Novellie, P.A. Plant species richness and composition a long livestock grazing intensity gradients in a Namaqualand (South Africa) protected area. Plant Ecology.2005,176:19-33.
[60]Hill, M.O., Evans, D.F., Bell, S.A. Long-term effects of excluding sheep from hill pastures in North Wales. Journal of Ecology.1992,80:1-13.
[61]Hjalten. J., Danell. K. Effect of simulated herbivory and intraspecific competition of the compensatory ability of birches. Ecology.1993,74:1136-1142.
[62]Hobbs, N.T. Modification of ecosystems by ungulates. Journal of Range Management.1996, 60:695-713.
[63]Hofstede, R.G.M. The effects of grazing and burning on soil and plant nutrient concentrations in Colombia Paramo grasslands. Plant and Soil.1995,173:111-132.
[64]Holland, E.A., Parton, W.J., Detling, J.K., et al. Physiological responses of plant populations to herbivory and their consequences for ecosystem nutrient flow. The American Naturalist. 1992,140:685-706.
[65]Holt, J.A. Grazing pressur e and soil carbon, microbial biomass and enzyme activit ies in sem-i arid nort heastern Australia. Applied Soil Ecology.1997,5:143-149.
[66]Illius, A.W., Gordon, I.A. The allometry of food intake in grazing ruminants. Journal of Animal Ecology.1987,56:989-999
[67]Jaramillo, V.J., Detling, J.K. Grazing history, defoliation, and competition:effects on short grass production and nitrogen accumulation. Ecology.1988,69:1599-1608.
[68]Jia, S., Li, S., Chen, Y., Dong, H., Guo, B. Soil physical properties and water regime in process of grassland degradation and restoration. In:Inner Mongolia Grassland Ecosystem Research Station (ed.), Research on Grassland Ecosystem, Part 5. Science, Beijing,1997. pp.111-117.
[69]Keller, A.A., Goldstein, R.A. Impact of carbon storage through restoration of drylands on the global carbon cycle. Environmental Management.1998,22:757-766.
[70]Klein, J.A., Harte, J., Zhao, X.Q. Experimental warning causes large and rapid species loss, dampened by simulated grazing, on the Tibetan Plateau. Ecology Letters.2004, 7:1170-1179.
[71]Kohler, F., Hamelin, J., Gillet, F., Gobat, J.M. Buttler, A. Soil microbial community changes in wooded mountain pastures due to simulated effects of cattle grazing. Plant and Soil. 2005,278:327-340.
[72]Johnston, A., Dormaar, J.F., Smoliak, S. Long-term grazing effects on fescue grassland soils. Journal of Range Management.1971,24:185-188.
[73]Lavado, R.S., Sierra, J.O., Hashimoto, P.N. Impact of grazing on soil nutrients in a Pampean grassland. Journal of Range Manage.1995,49:452-457.
[74]Lecain, D.R., Morgan, J.A., Schuman, G.E., Reeder, J.D., Hart, R.H. Carbon exchange and species composition of grazed pastures and exclosures in the short grass steppe of Colorado. Agriculture, Ecosystems and Environment.2002,93:421-435.
[75]Leps, J., Smilauer, P. Multivariate analysis of ecological data using CANOCO. Cambridge University Press, Cambridge, UK.2003.
[76]Liebig, M.A., Gros, S.J.R., Kronberg, S.L., Hanson, J.D., Frank, A.B., Phillips, R.L. Soil response to long-term grazing in the northern Great Plains of North America. Agriculture, Ecosystems and Environment.2006,115:270-276.
[77]Luo, Y.J., Qin, G.L., Du, G.Z. Importance of assemblage-level thinning:A field experiment in an alpine meadow on the Tibet plateau. Journal of Vegetation Science.2006,17:417-424.
[78]Ma, M.J., Zhou, X.H., Du, G.Z. Role of soil seed bank along a disturbance gradient in an alpine meadow on the Tibet plateau. Flora.2010,205:128-134.
[79]Magurran, A.E. Measuring biological diversity. Blackwell, Oxford.2004.
[80]McIntyre, S., Lavorel, S. Livestock grazing in subtropical pastures:stepps in the analysis of attribute response and plant functional types. Journal of Ecology.2001,89:209-226.
[81]Matches, A.G. Plant response to grazing:a review. Journal of Production Agriculture.1992, 5:1-7.
[82]McIntyre, S., Lavorel, S., Landsberg, J., Forbes, T.D.A. Disturbance response in vegetation towards a global perspective on functional traits. Journal of Vegetation Science.1999, 10:621-630.
[83]McIntyre, S., Lavorel, S. Livestock grazing in subtropical pastures:steps in the analysis of attribute response and plant functional types. Journal of Ecology.2001,89:209-226.
[84]McIntire, E.J.B., Hik, D.S. Influences of chronic and current season grazing by collared pikas on above-ground biomass and species richness in subarctic alpine meadows. Oecologia. 2005,145:288-297.
[85]McNaughton, S.J., Reuss, R.W., Seagle, S.W. Large mammals and process dynamics in African ecosystems. Biosciences.1988,38:794-800.
[86]McNaughton, S. J., MiIchunas, D. G., Frank, D. A. How can net primary production be measured in grazing ecosystems. Ecology.1996,77:974-977.
[87]McNaughton, S.J. Grassland herbivore Dynamics. In:Sinclair A.R.E., Griffiths M.N. (eds). Serengeti:Dynamics of an Ecosystem. University of Chicago, Illinois, USA.1979, pp46-81.
[88]Moretto, A.S., Distel, R.A. Soil nitrogen availability under grasses of different palatability in a temperate semi-arid rangeland of central Argentina. Austral Ecology.2002,27,509-514.
[89]Melinda, A. W., Trlica, M. J., Frasier, G.W, et al. Seasonal grazing affects soil physical properties of a montane riparian community. Journal of Range Management.2002,55:49- 56.
[90]Milchunas, D.G., Lauenroth, W.K. Quantitative effects of grazing on vegetation and soils over a range of environments. Ecological Monographs.1993,63:327-366.
[91]Milchunas, D.G., Sala, O.E., Lauenroth, W.K. A generalized model of effects of grazing by large herbivores on grassland community structure. The American Naturalists.1988, 132:87-106.
[92]Mwendera, E., Saleem, M.A.M., Woldu, Z. Vegetation response to cattle grazing in the Ethiopian highlands. Agriculture, Ecosystems and Environment.1997,64:43-51.
[93]Naeth, M.A., Bailey, A.W., Pluth, D.J., Chanasyk, D.S., Hardin, R.T. Grazing impacts on litter and soil organic matter in mixed prairie and fescue grassland ecosystems of Alberta. Journal of Range Management.1991,44:7-12.
[94]Naeth, M.A., Baron, V.S., Mapfumo, E., Dick, A.C., Okine, E.K., Chanasyk, D.S. Grazing intensity impacts on pasture carbon and nitrogen flow. Journal of Range Management. 2002,55:535-541.
[95]Niu, K.C., Zhang, S.T., Zhao, B.B., Du, G.Z. Linking grazing response of species abundance to functional traits in the Tibetan alpine meadow. Plant and Soil.2010,330:215-223.
[96]Noy-Meir, I., Gutman, M., Kaplan, Y. Responses of Mediterranean grassland plants to grazing and protection. Journal of Ecology.1989,77:290-310.
[97]Oesterheld, M. Effect of defoliation intensity on aboveground and belowground relative growth rates. Oecologia.1992,92:313-316.
[98]Olff, H., Ritchie, M. Effects of herbivores on grassland plant diversity. Trends in Ecology& Evolution.1998,13:261-265.
[99]Olff, H., Ritchie, M.E., Prins H.H.T. Global environmental controls of diversity in large herbivores. Nature.2002,415:901-904.
[100]Olofsson, J., Moen, J., Oksanen, L. Effects of herbivory on competition intensity in two arctic-alpine tundra communities with different productivity. Oikos.2002,96:265-272.
[101]Pakeman, R.J. Consistency of plant species and trait responses to grazing along a productivity gradient:a multi-site analysis. Journal of Ecology.2004,92:893-905.
[102]Persson, I.L., Danell, K., Bergstrom, R. Different moose densities and accompanied changes in tree morphology and browse production [J]. Ecological Application.2005, 15:1296-1305.
[103]Peco, B., de Pablos, I., Traba, J., Levassor, C. The effect of grazing and abandonment on species composition and functional traits:The case of Dehesa grasslands. Basic Applied Ecology.2005,6:175-183.
[104]Pei, S.F., Fu, H., Wan, C.G. Changes in soil properties and vegetation following exclosure and grazing in degraded Alxa desert steppe o f Inner Mongolia, China. Agriculture, Ecosystem & Environment.2008,124:33-39.
[105]Pierre, H. Effects of grazing on plant species composition and spatial distribution in grasslands of the Sahel. Plant Ecology.1998,138:191-202.
[106]Proulx, M., Mazumder, A. Reversal of grazing impact on plant species richness in nutrient-poor vs. nutrient-rich ecosystems. Ecology.1998,79:2581-2592.
[107]Price, P.W. The plant vigour hypothesis and herbivore attack. Oikos.1991,62:244-251.
[108]Skarpe, C. Impact of grazing in savanna ecosystems. Ambio.1991,20:351-356.
[109]Rauzi, F., Smith, F.M. Infiltration rates:three soils with three grazing levels in northeastern Colorada. Journal of Range Management.1973,26:126-129.
[110]Reeder, J.D., Schuman, G.E. Influence of livestock grazing on C sequestration in semi-rid mixed-grass and short-grass rangelands. Environmental Pollution.2002,116:457-463.
[111]Reich, P.B., Grigal, D.F., Aber, J.D., et al. Nitrogen mineralization and aboveground net primary production in 50 stands in a cold-temperate forest biome. Ecology,1997, 78:335-347.
[112]Ritchie, M.E., Tilman, D., Knops, J.M.H. Herbivore effects on plant and nitrogen dynamics in oak savanna. Ecology.1998,79:165-177.
[113]Rossignol, N., Bonis, A.J. Bouzill, B. Consequence of grazing pattern and vegetation structure on the spatial variations of net N mineralization in a wet grassland. Applied Soil Ecology.2006,31:62-72.
[114]Rusch, G.M., Oesterheld, M. Relationship between productivity, and species and functional group diversity in grazed and non-grazed Pampas grassland. Oikos.1997,78:519-526.
[115]Saatkamp, A., Romermann, C., Dutoit, T. Plant functional traits show nonlinear response to grazing. Folia Geobotanica.2010,45:239-252.
[116]Schuman, G.E., Reeder, J.D., Manley, J.T., Hart, R.H., Manley, W.A. Impact of grazing management on the carbon and nitrogen balance of a mixed-grass rangeland. Ecological Application.1999,9:65-71.
[117]Semmartin, M., Bella, C.D., de Salamone, I.G. Grazing-induced changes in plant species composition affect plant and soil properties of grassland mesocosms. Plant and Soil.2010, 328:471-481.
[118]Semmartin, M., Garibaldi, L.A., Chaneton, E.J. Grazing history effects on above and below-ground litter decomposition and nutrient cycling in two co-occurring grasses. Plant and Soil.2008,303:177-189.
[119]Semmartin, M., Oesterheld, M. Effect of grazing pattern and nitrogen availability on primary productivity. Oecologia.2001,126:225-230.
[120]Shiyomi, M. Spatial Pattern changes in aboveground plant biomass in a grazing pasture. Ecological research.1998,13:313-322.
[121]Shrestha, G., Stahl, P.D. Carbon accumulation and storage in semi-arid sagebrush steppe: Effects of long-term grazing exclusion. Agriculture Ecosystems & Environment,2008. 125:173-181.
[122]Skarpe, C., Aarrestad, P.A., Andreassen, H.P. et al. The return of the giants:ecological effects of an increasing elephant population. Ambio.2004,33:276-282.
[123]Stark, S., Grellmann, D. Soil microbial responses to herbivory in an arctic tundra heath at two levels of nutrient availability. Ecology.2002,83:2736-2744.
[124]Sternberg, M., Gutman, M., Perevolotsky, A., Ungar, E.D., Kigel, J. Vegetation response to grazing management in a Mediterranean herbaceous community:a functional group approach. Journal of Applied Ecology.2000,37:224-237.
[125]Stuefer, J.F., Huber, H. The role of stolon internodes for ramet survival after clone fragmentation in Potentilla anserine. Ecology Letters.1999,2:135-139.
[126]Sun, D.S., Wesche, K., Chen, D.D., Zhang, S.H., Wu, G.L., Du, G.Z., Comerford, N.B. Grazing depresses soil carbon storage through changing plant biomass and composition in a Tibetan alpine meadow. Plant Soil Environment.2011,57(6):271-278.
[127]Tilman, D. Plant strategies and the dynamics and structure of plant communities. Princeton University Press, Princeton, NJ.1988.
[128]Tracy, B.F., Frank, D.A. Herbivore influence on soil microbial biomass and nitrogen mineralization in a northern grassland ecosystem:Yellowstone National Park. Oecologia. 1998,114:556-562.
[129]Vail, S. G. Selection for overcompensatory plant responses to herbivory:a mechanism for the evolution of plant-herbivore mutualism. The American Naturalist.1992,139:1-8.
[130]van Wieren, S.E., Bakker, J.P. The impact of browsing and grazing herbivores on biodiversity. In:Gordon, I.J., Prins, H.H.T. (eds), The ecology of browsing and grazing. Springer.2008, pp.266.
[131]Vitousek, P.M., Gose, J.R., Grier, C.C. et al. A comparative analysis of potential nitrification and nitrate modicum production in soil under waterlogged conditions as an index of nitrogen availability, neutrality in forest ecosystem. Ecological Monographs.1982, 52:155-177.
[132]Vourc'h, G., Martin, J.L., Duncan, P., Escarre, J., Clausen, T. Defensive adaptations of Thuja plicata to ungulate browsing:a comparative study between mainland and island populations. Oecologia.2001,126:84-93.
[133]Wang, W.J., Chalk, P.M., Chen, D. et al. Nitrogen mineralization, immobilization and loss, and their role in determining differences in net nitrogen production during waterlogged and aerobic incubation of soils. Soil Biology & Biochemistry.2001,33(10):1305-1315.
[134]Wardle, D.A., Bonner, K.I., Barker, G.M. Linkages between plant litter decomposition, litter quality, and vegetation responses to herbivores. Functional Ecology.2002,16:585-595.
[135]Weis, A.E., Hochberg, M.E. The diverse effects of intraspecific competition on the selective advantage to resistance:a model and its predictions. The American Naturalist.2000, 156:276-292.
[136]Westoby, M. A leaf-height-seed (LHS) plant ecology strategy scheme. Plant and Soil.1998, 199:213-227.
[137]Westoby, M. The L-H-S strategy scheme in relation to grazing and fire. In:Eldridge, D., Freudenberger, D. (eds) VI International Rangeland Congress, Vol II, International Rangeland Congress, Townsville,1999,893-896.
[138]Wilson, S.D., Tilman, D. Quadratic variation in old field species richness along gradients of disturbance and nitrogen. Ecology.2002,83:492-504.
[139]Woodmansee, R.G., Dodd, J.L., Bowman, R.A., Clark, E.E., Dickinson, C.E. Nitrogen budget of a short grass prairie ecosystem. Oecologia.1978,34:363-376.
[140]Wood, S.N. Generalized additive models:an introduction with R. Chapman and Hall, London.2006.
[141]Wu, G.L., Du, G.Z., Liu, Z.H., Thirgood, S. Effect of fencing and grazing on a Kobresia-dominated meadow in the Qinghai-Tibetan Plateau. Plant and Soil.2009a,319:115-126.
[142]Wu, G.L., Li, X.P., Cheng, J.M., Wei, X.H., Sun, L. Grazing disturbances mediate species composition of alpine meadow based on seed size. Irish Journal of Ecology and Evolution. 2009b,55:369-379.
[143]Xu, Y., Li, L., Wang, Q. et al. The pattern between nitrogen mineralization and grazing intensities in an Inner Mongolian typical steppe. Plant and Soil.2007,300:289-300.
[144]Zhang, D.Y., Wang, G, Du, G.Z. Succession of the artifical grassland in the mountain grassland area of Gannan district, Gansu. Acta Phytoecologica et Geobotanica Snica.1990, 14:103-109.
[145]Zhang, Y.S., Werner, W., Scherer, H.W. et al. Effect of organic manure on organic Phosphorus fractions in two paddy soils. Biology and Fertility of Soils.1994,17:64-68.
[146]包文忠,山薇,杨晓东,等.我国北方草地资源面临的生态危机及对策.中国草地.1998,2：68-71.
[147]董全民,赵新全,马玉寿,等.牦牛放牧率和放牧季节对小嵩草高寒草甸土壤养分的影响[J].生态学杂志.2005,24(7)：729-735.
[148]杜睿,王庚辰,吕达仁.放牧对草原土壤N20产生及微生物的影响[J].环境科学.2001,22(4)：11-15.
[149]董晓玉,傅华,李旭东等.放牧与围封对黄土高原典型草原植物生物量及其碳氮磷贮量的影响[J].草业学报,2010,19(2)：175-182.
[150]郭继勋,祝廷成.羊草草原枯枝落叶积累的研究——枯枝落叶积累对草原生态环境及生产力的作用[J].草业科学.1994,11(6)：15-16.
[151]关世英,齐沛钦,康师安,等.不同牧压强度对草原土壤养分含量的影响初析[A].中国科学院海北高寒草甸生态系统定位站.草原生态系统研究(第5集)[C].北京：科学出版社.1997.17-22.
[152]关世英,张伟华.不同牧压强度对草原土壤水分、养分及其地上生物量的影响[J].干早区资源与环境.2000,14(4)：61-64.
[153]干友民,李志丹,泽柏,等.川西北亚高山草地不同退化梯度草地土壤养分变化[J].草业学报.2005,14(2)：38-42.
[154]蒋柏藩.石灰性土壤无机磷有效性的研究[J].土壤.1992,24：61-64.
[155]贾树海,崔学明,李绍良,等.牧压梯度上土壤物化性质的变化.见：中国科学院内蒙古草原生态系统定位研究站编.草原生态系统研究(第五集),北京：科学出版社.1996.pp12-16.
[156]贾慎修.草地学[M].北京：中国农业出版社.1995.
[157]李博.中国北方草地退化及其防治对策[J].中国农业科学.1997,30(6)：1-10.
[158]李贵才,韩兴国,黄建辉.森林生态系统土壤氮矿化影响因素研究进展[J].生态学报.2001,21(7)：1187-1195.
[159]李金华,李镇清,王刚.不同放牧强度对冷蒿和星毛委陵菜养分含量的影响[J].草业学报.2003,12：30-35.
[160]李金花,李镇清,任继周.放牧对草原植物的影响[J].草业学报.2002,11(1)：4-11.
[161]刘建秀,朱志红,郑伟.高寒草甸放牧扰动与两种植物的反应研究[J].西北植物学报.2005,25(10)：2043-2047.
[162]刘良梧,周建民,刘多森.农牧交错带不同利用方式下草原土壤的变化[J].土壤.1998,5：225-229.
[163]李青丰.草地畜牧业生产方式调整和生态环境治理对策—以锡林郭勒草原为例[J].草业科学.2002,增刊：296-301.
[164]李喜来.青藏高原“黑土滩”形成的自然因素与生物学机制[J].草业科学.2002,2：20-22.
[165]李香真,陈佐忠.不同放牧率对草原植物与土壤C、N、P含量的影响[J].草地学报. 1998,6(2)：90-98.
[166]李英年,赵新全,曹广民,等.海北高寒草甸生态系统定位站气候、植被生产力背景分析[J].高原气象.2004,28(4)：558-567.
[167]鲁如坤.土壤农业化学分析方法[M].北京：农业科技出版社,2000.
[168]李玉中,祝廷成,Redmann, R. E.三种利用类型羊草草地氮总矿化、硝化和无机氮消耗速率的比较研究[J].生态学报.2002,22(5)：668-673.
[169]马克平.试论生物多样性的概念[J].生物多样性.1993,1(1)：20-22.
[170]马玉寿,郎百宁,王启基.“黑土型”退化草地研究工作的回顾与展望[J].草业科学.1999,2：5-9.
[171]穆兴民,樊小林.土壤氮素矿化的生态模型研究[J].应用生态学报.1999,10(1)：114-118
[172]彭玉梅,崔鲜一,程渡.天然针茅草地生物量及营养动态研究[J].中国草食动物.1999,2：26-28.
[173]任继周.草地农业生态系统通论[M].安微：教育出版社.2004.
[174]任继周.草业科学研究方法[M].北京：中国农业出版社.1998.
[175]戎郁萍,韩建国,王培等.放牧强度对草地土壤理化性质的影响[J].中国草地.2001,23(4)：41-47.
[176]王德利,王岭.草食动物与草地植物多样性互作关系研究进展[J].草地学报.19,4：699-704.
[177]裴海昆.不同放牧强度对土壤养分及质地的影响[J].青海大学学报(自然科学版).2004,22(4)：29-31.
[178]王常慧.内蒙古温带典型草原土壤净氮矿化作用[D].北京：中国科学院植物研究所.2005.
[179]王常慧,邢雪荣,韩兴国.草地生态系统中土壤氮素矿化影响因素的研究进展[J].应用生态学报.2004.15：2148-2188.
[180]温明章,于丹,郭继勋.凋落物层对东北羊草草原微环境的影响[J].武汉植物学研究.2003,21(5)：395-400.
[181]王其兵,李林浩,白永飞,等.气候变化对草甸草原土壤氮素矿化影响的实验研究[J].植物生态学.2000.24(6)：687-692.
[182]王启兰,王长庭,杜岩功,等.放牧对高寒嵩草草甸土壤微生物量碳的影响及其与土壤环境的关系[J].草业学报.2008,17(2)：39-46.
[183]王淑强,胡直友.不同放牧强度对红三叶,黑麦草草地植被和土壤养分的影响[J].自然资源学报.1996,11(3)：280-287.
[184]王玉辉,何兴元.放牧强度对羊草草原的影响[J].草地学报.2002,10(1)：45-49.
[185]徐雨晴.家畜放牧对典型草原土壤-植被氮素转化的影响[D].北京：中国科学院植物研究所.2007.
[186]许中旗,闵庆文,王英舜,等.人为干扰对典型草原生态系统土壤养分状况的影响[J].水土保持学报.2006,20(5)：38-42.
[187]徐雨晴.家畜放牧对典型草原土壤-植被氮素转化的影响[D].北京：中国科学院植物研究所,2007.
[188]许志信,赵萌莉.韩国栋.内蒙古的生态环境退化及其防治对策[J].中国草地.2000,(5)：59-63.
[189]姚爱兴,王培,夏景新,攀奋成.不同放牧强度下奶牛对多年生黑麦草／白三叶草地 土壤特性的影响[J].草地学报.1995,3(3)：182-189.
[190]杨汝荣.我国西部草地退化原因及可持续发展分析[J].草业科学.2002,19(1)：23-27.
[191]张成霞,南志标.放牧对草地土壤理化特性影响的研究进展[J].草业学报.2010,19(4)：204-211.
[192]赵少华,宇万太,张璐,等.土壤有机磷研究进展[J].应用生态学报.2004,15(11)：2189-2192.
[193]张淑艳,李德新,徐光珍.放牧对短花针茅荒漠草原草群氮贮量分配及动态的影响[J].中国草地.1998,3(21)：13-16.
[194]张伟华,关世英.不同牧压强度对草原土壤水分、养分及其地上生物量的影响[J].干早区资源与环境.2000,14(4)：61-64.
[195]张蕴薇,韩建国,李志强.放牧强度对土壤物理性质的影响[J].草地学报.2002,10(1)：74-78
[2]Abril, A., Bucher, E.H. The effects of overg razing on soil microbial community and fertility in the Chaco dry savannas o f Argentina. Applied Soil Ecology.1999,12:159-167.
[3]Anderson, M.T., Ritchie, M.E., McNaughton, S.J. Rainfall and soils modify plant community response to grazing in Serengeti national park. Ecology.2007,88:1191-1201.
[4]Arnold, J.F. Plant life-form classification and its use in evaluating range conditions and trend. Journal of Range Management.1955,8:176-181.
[5]Augner, M., Tuomi, J., Rout, M. Effects of defoliation on competitive interactions in European white birch. Ecology.1997,78:2369-2377.
[6]Augustine, D.J., McNaughton, S.J. Ungulate effects of the functional species composition of plant communities:herbivore selectivity and plant tolerance. Journal of Wildlife Management.1998,62:1165-1183.
[7]Bardgett, R.D., Wardle, D.A. Herbivore-mediated linkages between aboveground and belowground communities. Ecology.2003,84:2258-2268.
[8]Barger, N.N., Ojima, D.S., Belnap, J., Wang, S.P., Wang, Y.F., Chen, Z.Z. Changes in plant functional groups, litter quality, and soil carbon and nitrogen mineralization with sheep grazing in an inner Mongolian grassland. Journal of Range Management.2004, 57:613-619.
[9]Baron, V.S., Mapfumo, E., Dick, A.C., Naeth, M.A., Okine, E.K., Chanasyk, D.S. Grazing intensity impacts on pasture carbon and nitrogen flow. Journal of Range Management.2002,55:535-541.
[10]Bauer, A., Cote, C.V., Blank, A.L. Soil property comparison in virgin grass lands between grazed and non-grazed management systems. Soil Science Society of American Journal. 1987,51:176-182.
[11]Belsky, A.J. Does herbivore benefit plants? A review of the evidence. The American Naturalist.1986,127:871-891.
[12]Bergelson, J., Juenger, T, Crawley, M.J. Regrowth following herbivory in Ipomopsis aggregata:compensation but not overcompensation. The American Naturalist.1996, 148:744-755.
[13]Bowman, R.A., Cole, C.V. An exploratory method for fractionation of organic phosphorus from grassland soil. Soil Science.1978,125:95-101.
[14]Bullock, J.M., Franklin, J., Stevenson, M.J., Silvertown, J., et al. A plant trait analysis of responses to grazing in a long-term experiment. Journal of Applied Ecology.2001,38: 253-267.
[15]Cao, GM, Tang, Y.H., Mo, W.H., Wang, Y.S., Li, Y.N., Zhao, X.Q. Grazing intensity alters soil respiration in an alpine meadow on the Tibetan plateau. Soil Biology and Biochemistry. 2004,36:237-243.
[16]Chaneton, E. J., Lemcoff, J.H., Lavado, R.S. Nitrogen and phosphorus cycling in grazed and ungrazed plots in a temperate subhumid grass land in Argentina. Applied Ecology.1996, 33:291-302.
[17]Chen, D.D., Zhang, S.H., Dong, S.K., Wang, X.T., Du, G.Z.. Effect of land-use on soil nutrients and microbial biomass of an alpine regiona on the northeatern Tibetan Plateau, China. Land Degradation and Development.2010,21(5):446-452.
[18]Cingolani, A.M., Posse, G., Collantes, M.B. Plant functional traits, herbivore selectivity and response to sheep grazing in Patagonian steppe grasslands. Journal of Applied Ecology. 2005a,42:50-59.
[19]Cingolani, A.M., Noy-Meir, I., Diaz, S. Grazing effects on rangeland diversity:a synthesis of contemporary models. Ecological Application.2005b,15:757-773.
[20]Conant, R.T., Paustian, K., Elliott, E.T., Grassland management and conversion into grassland: effects on soil carbon. Applied Ecology.2011,11:343-355.
[21]Cosyns, E., Delporte, A., Lens, L., Hoffmann, M. Germination success of temperate grassland species after passage through ungulate and rabbit guts. Journal of Ecology.2005, 93:353-361.
[22]Coley, P.D., Bryant, J.P., Chapin, F.S. Resource availability and plant anti-herbivore defense. Science.1985,230:895-899.
[23]Connell, J. H. Diversity in tropical rain forests and coral reefs. Science.1978, 199:1302-1310.
[24]Cui, X.Y., Wang, Y.F., Niu, H.S., Wu, J., Wang, S.P., Schnug, E., Rogasik, J., Fleckenstein, J., Tang, Y.H. Effect of long-term grazing on soil organic carbon content in semiarid steppes in Inner Mongolia. Ecological Research.2005,20:519-527.
[25]Dahlgren, R.A., Singer, M.J., Huang, X. Oak tree and grazing impacts on soil properties and nutrients in California oak woodland. Biochemistry.1997,39:45-64.
[26]Danell, K., Bergstrom, R., Edenius, L., Ericsson, G. Ungulates as drivers of tree population dynamics at module and genet levels. Forest Ecology and Management.2003,181:67-76.
[27]Danell, K., Hjalten, J., Ericson, L., Elmqvist, T. Vole feeding on male and female willow shoots along a gradient of plant productivity. Oikos.1991,62:145-152.
[28]De Bello, F., Leps, J.A.N., Sebastia, M.T. Predictive value of plant traits to grazing along a climatic gradient in the Mediterranean. Journal of Applied Ecology.2005.42:824-833.
[29]De Deyn, G.B., Cornelissen, J.H.C., Bardgett, R.D. Plant functional traits and soil carbon sequestration in contrasting biomes. Ecology Letters.2008,11:516-531.
[30]Derner, J.D., Briske, D.D., Boutton, T.W. Does grazing mediate soil carbon and nitrogen accumulation beneath C4 perennial grasses along an environmental gradient? Plant and Soil.1997,191:147-156.
[31]Diaz, S., Lavorel, S., McIntyer, S. et al. Plant trait responses to grazing-a global synthesis. Global Change Biology.2007,13:313-341.
[32]Dray, S., Dufour, A.B., Chessel, D. The ade4-package:two-table and K-table methods. R News.2007,7:47-52.
[33]Doledec, S., Chessel, D., ter Braak, C. J. F., et al. Matching species traits to environmental variables:a new three-table ordination method. Environment Ecology Statistics.1996, 3:143-166.
[34]Dyksterhuis, E.J. Condition and management of rangelands based on quantitative ecology. Journal of Range Management.1949,2:104-115.
[35]Eviner, V. T., Chapin, F. S. Functional matrix:A conceptual framework for predicting multiple plant effects on ecosystem processes. Annual Review of Ecology and Systematics. 2003,34:455-485.
[36]Evju, M., Austrheim, G., Halvorsen, R., Mysterud, A. Grazing responses in herbs in relation to herbivore selectivity and plant traits in an alpine ecosystem. Oecologia.2009,161: 77-85.
[37]Ferris, J. C. Growth and nitrogen mineralization of selected fungi and fungal-feeding nematodes on sand amended with organic matter. Plant and Soil.2000,218:91-101.
[38]Friesen, D.K., Blair, GJ. A dual radiotracer study of transformations of organic, inorganic and plant residue phosphorus in soil in the presence and absence of plants. Australian Journal of Soil Research.1988,26:355-366.
[39]Frank, D.A. Groffman, P.M. Ungulate vs. landscape control of soil C and Nprocesses in grasslands of Yellowstone National Park. Ecology.1998,79:2229-2241.
[40]Frank, A.B., Tanaka, D.L., Hofmann, L., et al. Soil carbon and nitrogen of Northern Great Plains grasslands as influenced by long-term grazing. Journal of Range Management.1995, 48(5):470-474.
[41]Gao, Y.H., Luo, P., Wu, N., Yi, S.L., Chen, H. Biomass and nitrogen response to grazing intensity in an alpine meadow on the Eastern Tibetan Plateau. Polish Journal of Ecology. 2007,53,469-479.
[42]Gao, Y.H., Luo, P., Wu, N., Chen, H., Wang, G.X. Impacts of grazing intensity on nitrogen pools and nitrogen cycle in an alpine meadow on the eastern Qinghai-Tibetan Plateau. Applied Ecology and Environment Research.2008,6:69-79.
[43]Gao, Y.H., Schumann, M., Chen, H., Wu, N., Luo, P. Impacts of grazing intensity on soil carbon and nitrogen in an alpine meadow on the eastern Tibetan Plateau. Journal of Food, Agriculture and Environment.2009,7:749-754.
[44]Gibson, D.J. Grasses and grassland ecology. Oxford University Press Inc., New York.2009.
[45]Gifford, G.F., Hawkins, R.H. Hydrologic impact of grazing on infiltration:acritical review. Water Resource Research.1978,14:305-313.
[46]Grayston, S.J., Vaughan, D., Jones, D. Rhizosphere carbon flow in trees, in comparison with annual plants:the importance of root exudation and its impact on microbial activity and nutrient availability. Applied Soil Ecology.1996,5:29-56.
[47]Greene, R.S.B., Kinnell, P.I.A., Wood, J.T. Role of plant cover and stock tramp ling on runoff and soil erosion from semiarid wooded rangelands. Australian Journal of Soil Research. 1994,32:953-973.
[48]Guerif, J. Factors influencing compaction induced increases in soil strength. Soil& Tillage Research.1990,16:167-178.
[49]Grime, J.P. Plant strategies and vegetation processes. Wiley, Chichester.1999.
[50]Grime, J.P. Plant Strategies, Vegetation Processes, and Ecosystem Properties,2nd edn. John Wiley and Sons, Chichester.2001.
[51]Grime, J.P., Cornelissen, J.H.C., Thompson, K., Hodgson, J.G. Evidence of a causal connection between anti-herbivore defense and the decomposition rate of leaves. Oikos. 1996,77:489-494.
[52]Grubb, P. A positive distrust in simplicity. Journal of Ecology.1992,80:585-610.
[53]Han, G.D., Hao, X.Y., Zhao, M.L, et al. Effect of grazing intensity on carbon and nitrogen in soil and vegetation in a meadow steppe in Inner Mongolia. Agriculture, Ecosystems & Environment.2008,125:21-32.
[54]Han, W.W., Luo, Y.J., Du, G.Z. Effects of clipping on diversity and above-ground biomass associated with soil fertility on an alpine meadow in the eastern region of the Qinghai-Tibetan Plateau. New Zealand Journal of Agricultural Research.2007, 50:361-368.
[55]Hastie, T.J., Tibshirani, R.J. Generalized additive models. Chapman and Hall, London.1990.
[56]Hassink, J.,Bouwman,L. A.,Zwart,K. B., et al. Relationships between habitable pore space, soil biota and mineralization rates in grassland soils. Soil Biology & Biochemistry.1993, 25:47-55.
[57]Haynes, R.J., Williams, P.H. Nutrient cycling and soil fertility in the grazed pasture ecosystem. Advances in Agronomy.1993,49:119-199.
[58]Hejduk, S., Hrabe, F. Influence of different systems of grazing, type of swards and fertilizing on underground phytomass of pastures. Plant, Soil and Environment.2003,49:18-23.
[59]Hendricks, H.H., Bond, W.J., Midgley, J.J., Novellie, P.A. Plant species richness and composition a long livestock grazing intensity gradients in a Namaqualand (South Africa) protected area. Plant Ecology.2005,176:19-33.
[60]Hill, M.O., Evans, D.F., Bell, S.A. Long-term effects of excluding sheep from hill pastures in North Wales. Journal of Ecology.1992,80:1-13.
[61]Hjalten. J., Danell. K. Effect of simulated herbivory and intraspecific competition of the compensatory ability of birches. Ecology.1993,74:1136-1142.
[62]Hobbs, N.T. Modification of ecosystems by ungulates. Journal of Range Management.1996, 60:695-713.
[63]Hofstede, R.G.M. The effects of grazing and burning on soil and plant nutrient concentrations in Colombia Paramo grasslands. Plant and Soil.1995,173:111-132.
[64]Holland, E.A., Parton, W.J., Detling, J.K., et al. Physiological responses of plant populations to herbivory and their consequences for ecosystem nutrient flow. The American Naturalist. 1992,140:685-706.
[65]Holt, J.A. Grazing pressur e and soil carbon, microbial biomass and enzyme activit ies in sem-i arid nort heastern Australia. Applied Soil Ecology.1997,5:143-149.
[66]Illius, A.W., Gordon, I.A. The allometry of food intake in grazing ruminants. Journal of Animal Ecology.1987,56:989-999
[67]Jaramillo, V.J., Detling, J.K. Grazing history, defoliation, and competition:effects on short grass production and nitrogen accumulation. Ecology.1988,69:1599-1608.
[68]Jia, S., Li, S., Chen, Y., Dong, H., Guo, B. Soil physical properties and water regime in process of grassland degradation and restoration. In:Inner Mongolia Grassland Ecosystem Research Station (ed.), Research on Grassland Ecosystem, Part 5. Science, Beijing,1997. pp.111-117.
[69]Keller, A.A., Goldstein, R.A. Impact of carbon storage through restoration of drylands on the global carbon cycle. Environmental Management.1998,22:757-766.
[70]Klein, J.A., Harte, J., Zhao, X.Q. Experimental warning causes large and rapid species loss, dampened by simulated grazing, on the Tibetan Plateau. Ecology Letters.2004, 7:1170-1179.
[71]Kohler, F., Hamelin, J., Gillet, F., Gobat, J.M. Buttler, A. Soil microbial community changes in wooded mountain pastures due to simulated effects of cattle grazing. Plant and Soil. 2005,278:327-340.
[72]Johnston, A., Dormaar, J.F., Smoliak, S. Long-term grazing effects on fescue grassland soils. Journal of Range Management.1971,24:185-188.
[73]Lavado, R.S., Sierra, J.O., Hashimoto, P.N. Impact of grazing on soil nutrients in a Pampean grassland. Journal of Range Manage.1995,49:452-457.
[74]Lecain, D.R., Morgan, J.A., Schuman, G.E., Reeder, J.D., Hart, R.H. Carbon exchange and species composition of grazed pastures and exclosures in the short grass steppe of Colorado. Agriculture, Ecosystems and Environment.2002,93:421-435.
[75]Leps, J., Smilauer, P. Multivariate analysis of ecological data using CANOCO. Cambridge University Press, Cambridge, UK.2003.
[76]Liebig, M.A., Gros, S.J.R., Kronberg, S.L., Hanson, J.D., Frank, A.B., Phillips, R.L. Soil response to long-term grazing in the northern Great Plains of North America. Agriculture, Ecosystems and Environment.2006,115:270-276.
[77]Luo, Y.J., Qin, G.L., Du, G.Z. Importance of assemblage-level thinning:A field experiment in an alpine meadow on the Tibet plateau. Journal of Vegetation Science.2006,17:417-424.
[78]Ma, M.J., Zhou, X.H., Du, G.Z. Role of soil seed bank along a disturbance gradient in an alpine meadow on the Tibet plateau. Flora.2010,205:128-134.
[79]Magurran, A.E. Measuring biological diversity. Blackwell, Oxford.2004.
[80]McIntyre, S., Lavorel, S. Livestock grazing in subtropical pastures:stepps in the analysis of attribute response and plant functional types. Journal of Ecology.2001,89:209-226.
[81]Matches, A.G. Plant response to grazing:a review. Journal of Production Agriculture.1992, 5:1-7.
[82]McIntyre, S., Lavorel, S., Landsberg, J., Forbes, T.D.A. Disturbance response in vegetation towards a global perspective on functional traits. Journal of Vegetation Science.1999, 10:621-630.
[83]McIntyre, S., Lavorel, S. Livestock grazing in subtropical pastures:steps in the analysis of attribute response and plant functional types. Journal of Ecology.2001,89:209-226.
[84]McIntire, E.J.B., Hik, D.S. Influences of chronic and current season grazing by collared pikas on above-ground biomass and species richness in subarctic alpine meadows. Oecologia. 2005,145:288-297.
[85]McNaughton, S.J., Reuss, R.W., Seagle, S.W. Large mammals and process dynamics in African ecosystems. Biosciences.1988,38:794-800.
[86]McNaughton, S. J., MiIchunas, D. G., Frank, D. A. How can net primary production be measured in grazing ecosystems. Ecology.1996,77:974-977.
[87]McNaughton, S.J. Grassland herbivore Dynamics. In:Sinclair A.R.E., Griffiths M.N. (eds). Serengeti:Dynamics of an Ecosystem. University of Chicago, Illinois, USA.1979, pp46-81.
[88]Moretto, A.S., Distel, R.A. Soil nitrogen availability under grasses of different palatability in a temperate semi-arid rangeland of central Argentina. Austral Ecology.2002,27,509-514.
[89]Melinda, A. W., Trlica, M. J., Frasier, G.W, et al. Seasonal grazing affects soil physical properties of a montane riparian community. Journal of Range Management.2002,55:49- 56.
[90]Milchunas, D.G., Lauenroth, W.K. Quantitative effects of grazing on vegetation and soils over a range of environments. Ecological Monographs.1993,63:327-366.
[91]Milchunas, D.G., Sala, O.E., Lauenroth, W.K. A generalized model of effects of grazing by large herbivores on grassland community structure. The American Naturalists.1988, 132:87-106.
[92]Mwendera, E., Saleem, M.A.M., Woldu, Z. Vegetation response to cattle grazing in the Ethiopian highlands. Agriculture, Ecosystems and Environment.1997,64:43-51.
[93]Naeth, M.A., Bailey, A.W., Pluth, D.J., Chanasyk, D.S., Hardin, R.T. Grazing impacts on litter and soil organic matter in mixed prairie and fescue grassland ecosystems of Alberta. Journal of Range Management.1991,44:7-12.
[94]Naeth, M.A., Baron, V.S., Mapfumo, E., Dick, A.C., Okine, E.K., Chanasyk, D.S. Grazing intensity impacts on pasture carbon and nitrogen flow. Journal of Range Management. 2002,55:535-541.
[95]Niu, K.C., Zhang, S.T., Zhao, B.B., Du, G.Z. Linking grazing response of species abundance to functional traits in the Tibetan alpine meadow. Plant and Soil.2010,330:215-223.
[96]Noy-Meir, I., Gutman, M., Kaplan, Y. Responses of Mediterranean grassland plants to grazing and protection. Journal of Ecology.1989,77:290-310.
[97]Oesterheld, M. Effect of defoliation intensity on aboveground and belowground relative growth rates. Oecologia.1992,92:313-316.
[98]Olff, H., Ritchie, M. Effects of herbivores on grassland plant diversity. Trends in Ecology& Evolution.1998,13:261-265.
[99]Olff, H., Ritchie, M.E., Prins H.H.T. Global environmental controls of diversity in large herbivores. Nature.2002,415:901-904.
[100]Olofsson, J., Moen, J., Oksanen, L. Effects of herbivory on competition intensity in two arctic-alpine tundra communities with different productivity. Oikos.2002,96:265-272.
[101]Pakeman, R.J. Consistency of plant species and trait responses to grazing along a productivity gradient:a multi-site analysis. Journal of Ecology.2004,92:893-905.
[102]Persson, I.L., Danell, K., Bergstrom, R. Different moose densities and accompanied changes in tree morphology and browse production [J]. Ecological Application.2005, 15:1296-1305.
[103]Peco, B., de Pablos, I., Traba, J., Levassor, C. The effect of grazing and abandonment on species composition and functional traits:The case of Dehesa grasslands. Basic Applied Ecology.2005,6:175-183.
[104]Pei, S.F., Fu, H., Wan, C.G. Changes in soil properties and vegetation following exclosure and grazing in degraded Alxa desert steppe o f Inner Mongolia, China. Agriculture, Ecosystem & Environment.2008,124:33-39.
[105]Pierre, H. Effects of grazing on plant species composition and spatial distribution in grasslands of the Sahel. Plant Ecology.1998,138:191-202.
[106]Proulx, M., Mazumder, A. Reversal of grazing impact on plant species richness in nutrient-poor vs. nutrient-rich ecosystems. Ecology.1998,79:2581-2592.
[107]Price, P.W. The plant vigour hypothesis and herbivore attack. Oikos.1991,62:244-251.
[108]Skarpe, C. Impact of grazing in savanna ecosystems. Ambio.1991,20:351-356.
[109]Rauzi, F., Smith, F.M. Infiltration rates:three soils with three grazing levels in northeastern Colorada. Journal of Range Management.1973,26:126-129.
[110]Reeder, J.D., Schuman, G.E. Influence of livestock grazing on C sequestration in semi-rid mixed-grass and short-grass rangelands. Environmental Pollution.2002,116:457-463.
[111]Reich, P.B., Grigal, D.F., Aber, J.D., et al. Nitrogen mineralization and aboveground net primary production in 50 stands in a cold-temperate forest biome. Ecology,1997, 78:335-347.
[112]Ritchie, M.E., Tilman, D., Knops, J.M.H. Herbivore effects on plant and nitrogen dynamics in oak savanna. Ecology.1998,79:165-177.
[113]Rossignol, N., Bonis, A.J. Bouzill, B. Consequence of grazing pattern and vegetation structure on the spatial variations of net N mineralization in a wet grassland. Applied Soil Ecology.2006,31:62-72.
[114]Rusch, G.M., Oesterheld, M. Relationship between productivity, and species and functional group diversity in grazed and non-grazed Pampas grassland. Oikos.1997,78:519-526.
[115]Saatkamp, A., Romermann, C., Dutoit, T. Plant functional traits show nonlinear response to grazing. Folia Geobotanica.2010,45:239-252.
[116]Schuman, G.E., Reeder, J.D., Manley, J.T., Hart, R.H., Manley, W.A. Impact of grazing management on the carbon and nitrogen balance of a mixed-grass rangeland. Ecological Application.1999,9:65-71.
[117]Semmartin, M., Bella, C.D., de Salamone, I.G. Grazing-induced changes in plant species composition affect plant and soil properties of grassland mesocosms. Plant and Soil.2010, 328:471-481.
[118]Semmartin, M., Garibaldi, L.A., Chaneton, E.J. Grazing history effects on above and below-ground litter decomposition and nutrient cycling in two co-occurring grasses. Plant and Soil.2008,303:177-189.
[119]Semmartin, M., Oesterheld, M. Effect of grazing pattern and nitrogen availability on primary productivity. Oecologia.2001,126:225-230.
[120]Shiyomi, M. Spatial Pattern changes in aboveground plant biomass in a grazing pasture. Ecological research.1998,13:313-322.
[121]Shrestha, G., Stahl, P.D. Carbon accumulation and storage in semi-arid sagebrush steppe: Effects of long-term grazing exclusion. Agriculture Ecosystems & Environment,2008. 125:173-181.
[122]Skarpe, C., Aarrestad, P.A., Andreassen, H.P. et al. The return of the giants:ecological effects of an increasing elephant population. Ambio.2004,33:276-282.
[123]Stark, S., Grellmann, D. Soil microbial responses to herbivory in an arctic tundra heath at two levels of nutrient availability. Ecology.2002,83:2736-2744.
[124]Sternberg, M., Gutman, M., Perevolotsky, A., Ungar, E.D., Kigel, J. Vegetation response to grazing management in a Mediterranean herbaceous community:a functional group approach. Journal of Applied Ecology.2000,37:224-237.
[125]Stuefer, J.F., Huber, H. The role of stolon internodes for ramet survival after clone fragmentation in Potentilla anserine. Ecology Letters.1999,2:135-139.
[126]Sun, D.S., Wesche, K., Chen, D.D., Zhang, S.H., Wu, G.L., Du, G.Z., Comerford, N.B. Grazing depresses soil carbon storage through changing plant biomass and composition in a Tibetan alpine meadow. Plant Soil Environment.2011,57(6):271-278.
[127]Tilman, D. Plant strategies and the dynamics and structure of plant communities. Princeton University Press, Princeton, NJ.1988.
[128]Tracy, B.F., Frank, D.A. Herbivore influence on soil microbial biomass and nitrogen mineralization in a northern grassland ecosystem:Yellowstone National Park. Oecologia. 1998,114:556-562.
[129]Vail, S. G. Selection for overcompensatory plant responses to herbivory:a mechanism for the evolution of plant-herbivore mutualism. The American Naturalist.1992,139:1-8.
[130]van Wieren, S.E., Bakker, J.P. The impact of browsing and grazing herbivores on biodiversity. In:Gordon, I.J., Prins, H.H.T. (eds), The ecology of browsing and grazing. Springer.2008, pp.266.
[131]Vitousek, P.M., Gose, J.R., Grier, C.C. et al. A comparative analysis of potential nitrification and nitrate modicum production in soil under waterlogged conditions as an index of nitrogen availability, neutrality in forest ecosystem. Ecological Monographs.1982, 52:155-177.
[132]Vourc'h, G., Martin, J.L., Duncan, P., Escarre, J., Clausen, T. Defensive adaptations of Thuja plicata to ungulate browsing:a comparative study between mainland and island populations. Oecologia.2001,126:84-93.
[133]Wang, W.J., Chalk, P.M., Chen, D. et al. Nitrogen mineralization, immobilization and loss, and their role in determining differences in net nitrogen production during waterlogged and aerobic incubation of soils. Soil Biology & Biochemistry.2001,33(10):1305-1315.
[134]Wardle, D.A., Bonner, K.I., Barker, G.M. Linkages between plant litter decomposition, litter quality, and vegetation responses to herbivores. Functional Ecology.2002,16:585-595.
[135]Weis, A.E., Hochberg, M.E. The diverse effects of intraspecific competition on the selective advantage to resistance:a model and its predictions. The American Naturalist.2000, 156:276-292.
[136]Westoby, M. A leaf-height-seed (LHS) plant ecology strategy scheme. Plant and Soil.1998, 199:213-227.
[137]Westoby, M. The L-H-S strategy scheme in relation to grazing and fire. In:Eldridge, D., Freudenberger, D. (eds) VI International Rangeland Congress, Vol II, International Rangeland Congress, Townsville,1999,893-896.
[138]Wilson, S.D., Tilman, D. Quadratic variation in old field species richness along gradients of disturbance and nitrogen. Ecology.2002,83:492-504.
[139]Woodmansee, R.G., Dodd, J.L., Bowman, R.A., Clark, E.E., Dickinson, C.E. Nitrogen budget of a short grass prairie ecosystem. Oecologia.1978,34:363-376.
[140]Wood, S.N. Generalized additive models:an introduction with R. Chapman and Hall, London.2006.
[141]Wu, G.L., Du, G.Z., Liu, Z.H., Thirgood, S. Effect of fencing and grazing on a Kobresia-dominated meadow in the Qinghai-Tibetan Plateau. Plant and Soil.2009a,319:115-126.
[142]Wu, G.L., Li, X.P., Cheng, J.M., Wei, X.H., Sun, L. Grazing disturbances mediate species composition of alpine meadow based on seed size. Irish Journal of Ecology and Evolution. 2009b,55:369-379.
[143]Xu, Y., Li, L., Wang, Q. et al. The pattern between nitrogen mineralization and grazing intensities in an Inner Mongolian typical steppe. Plant and Soil.2007,300:289-300.
[144]Zhang, D.Y., Wang, G, Du, G.Z. Succession of the artifical grassland in the mountain grassland area of Gannan district, Gansu. Acta Phytoecologica et Geobotanica Snica.1990, 14:103-109.
[145]Zhang, Y.S., Werner, W., Scherer, H.W. et al. Effect of organic manure on organic Phosphorus fractions in two paddy soils. Biology and Fertility of Soils.1994,17:64-68.
[146]包文忠,山薇,杨晓东,等.我国北方草地资源面临的生态危机及对策.中国草地.1998,2：68-71.
[147]董全民,赵新全,马玉寿,等.牦牛放牧率和放牧季节对小嵩草高寒草甸土壤养分的影响[J].生态学杂志.2005,24(7)：729-735.
[148]杜睿,王庚辰,吕达仁.放牧对草原土壤N20产生及微生物的影响[J].环境科学.2001,22(4)：11-15.
[149]董晓玉,傅华,李旭东等.放牧与围封对黄土高原典型草原植物生物量及其碳氮磷贮量的影响[J].草业学报,2010,19(2)：175-182.
[150]郭继勋,祝廷成.羊草草原枯枝落叶积累的研究——枯枝落叶积累对草原生态环境及生产力的作用[J].草业科学.1994,11(6)：15-16.
[151]关世英,齐沛钦,康师安,等.不同牧压强度对草原土壤养分含量的影响初析[A].中国科学院海北高寒草甸生态系统定位站.草原生态系统研究(第5集)[C].北京：科学出版社.1997.17-22.
[152]关世英,张伟华.不同牧压强度对草原土壤水分、养分及其地上生物量的影响[J].干早区资源与环境.2000,14(4)：61-64.
[153]干友民,李志丹,泽柏,等.川西北亚高山草地不同退化梯度草地土壤养分变化[J].草业学报.2005,14(2)：38-42.
[154]蒋柏藩.石灰性土壤无机磷有效性的研究[J].土壤.1992,24：61-64.
[155]贾树海,崔学明,李绍良,等.牧压梯度上土壤物化性质的变化.见：中国科学院内蒙古草原生态系统定位研究站编.草原生态系统研究(第五集),北京：科学出版社.1996.pp12-16.
[156]贾慎修.草地学[M].北京：中国农业出版社.1995.
[157]李博.中国北方草地退化及其防治对策[J].中国农业科学.1997,30(6)：1-10.
[158]李贵才,韩兴国,黄建辉.森林生态系统土壤氮矿化影响因素研究进展[J].生态学报.2001,21(7)：1187-1195.
[159]李金华,李镇清,王刚.不同放牧强度对冷蒿和星毛委陵菜养分含量的影响[J].草业学报.2003,12：30-35.
[160]李金花,李镇清,任继周.放牧对草原植物的影响[J].草业学报.2002,11(1)：4-11.
[161]刘建秀,朱志红,郑伟.高寒草甸放牧扰动与两种植物的反应研究[J].西北植物学报.2005,25(10)：2043-2047.
[162]刘良梧,周建民,刘多森.农牧交错带不同利用方式下草原土壤的变化[J].土壤.1998,5：225-229.
[163]李青丰.草地畜牧业生产方式调整和生态环境治理对策—以锡林郭勒草原为例[J].草业科学.2002,增刊：296-301.
[164]李喜来.青藏高原“黑土滩”形成的自然因素与生物学机制[J].草业科学.2002,2：20-22.
[165]李香真,陈佐忠.不同放牧率对草原植物与土壤C、N、P含量的影响[J].草地学报. 1998,6(2)：90-98.
[166]李英年,赵新全,曹广民,等.海北高寒草甸生态系统定位站气候、植被生产力背景分析[J].高原气象.2004,28(4)：558-567.
[167]鲁如坤.土壤农业化学分析方法[M].北京：农业科技出版社,2000.
[168]李玉中,祝廷成,Redmann, R. E.三种利用类型羊草草地氮总矿化、硝化和无机氮消耗速率的比较研究[J].生态学报.2002,22(5)：668-673.
[169]马克平.试论生物多样性的概念[J].生物多样性.1993,1(1)：20-22.
[170]马玉寿,郎百宁,王启基.“黑土型”退化草地研究工作的回顾与展望[J].草业科学.1999,2：5-9.
[171]穆兴民,樊小林.土壤氮素矿化的生态模型研究[J].应用生态学报.1999,10(1)：114-118
[172]彭玉梅,崔鲜一,程渡.天然针茅草地生物量及营养动态研究[J].中国草食动物.1999,2：26-28.
[173]任继周.草地农业生态系统通论[M].安微：教育出版社.2004.
[174]任继周.草业科学研究方法[M].北京：中国农业出版社.1998.
[175]戎郁萍,韩建国,王培等.放牧强度对草地土壤理化性质的影响[J].中国草地.2001,23(4)：41-47.
[176]王德利,王岭.草食动物与草地植物多样性互作关系研究进展[J].草地学报.19,4：699-704.
[177]裴海昆.不同放牧强度对土壤养分及质地的影响[J].青海大学学报(自然科学版).2004,22(4)：29-31.
[178]王常慧.内蒙古温带典型草原土壤净氮矿化作用[D].北京：中国科学院植物研究所.2005.
[179]王常慧,邢雪荣,韩兴国.草地生态系统中土壤氮素矿化影响因素的研究进展[J].应用生态学报.2004.15：2148-2188.
[180]温明章,于丹,郭继勋.凋落物层对东北羊草草原微环境的影响[J].武汉植物学研究.2003,21(5)：395-400.
[181]王其兵,李林浩,白永飞,等.气候变化对草甸草原土壤氮素矿化影响的实验研究[J].植物生态学.2000.24(6)：687-692.
[182]王启兰,王长庭,杜岩功,等.放牧对高寒嵩草草甸土壤微生物量碳的影响及其与土壤环境的关系[J].草业学报.2008,17(2)：39-46.
[183]王淑强,胡直友.不同放牧强度对红三叶,黑麦草草地植被和土壤养分的影响[J].自然资源学报.1996,11(3)：280-287.
[184]王玉辉,何兴元.放牧强度对羊草草原的影响[J].草地学报.2002,10(1)：45-49.
[185]徐雨晴.家畜放牧对典型草原土壤-植被氮素转化的影响[D].北京：中国科学院植物研究所.2007.
[186]许中旗,闵庆文,王英舜,等.人为干扰对典型草原生态系统土壤养分状况的影响[J].水土保持学报.2006,20(5)：38-42.
[187]徐雨晴.家畜放牧对典型草原土壤-植被氮素转化的影响[D].北京：中国科学院植物研究所,2007.
[188]许志信,赵萌莉.韩国栋.内蒙古的生态环境退化及其防治对策[J].中国草地.2000,(5)：59-63.
[189]姚爱兴,王培,夏景新,攀奋成.不同放牧强度下奶牛对多年生黑麦草／白三叶草地 土壤特性的影响[J].草地学报.1995,3(3)：182-189.
[190]杨汝荣.我国西部草地退化原因及可持续发展分析[J].草业科学.2002,19(1)：23-27.
[191]张成霞,南志标.放牧对草地土壤理化特性影响的研究进展[J].草业学报.2010,19(4)：204-211.
[192]赵少华,宇万太,张璐,等.土壤有机磷研究进展[J].应用生态学报.2004,15(11)：2189-2192.
[193]张淑艳,李德新,徐光珍.放牧对短花针茅荒漠草原草群氮贮量分配及动态的影响[J].中国草地.1998,3(21)：13-16.
[194]张伟华,关世英.不同牧压强度对草原土壤水分、养分及其地上生物量的影响[J].干早区资源与环境.2000,14(4)：61-64.
[195]张蕴薇,韩建国,李志强.放牧强度对土壤物理性质的影响[J].草地学报.2002,10(1)：74-78
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