Effects of grazing management system on plant community structure and functioning in a semiarid steppe: scaling from species to community
Effects of grazing management system on plant community structure and functioning in a semiarid steppe: scaling from species to community
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DOI：
10.1007/s11104-010-0661-2
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发表时间：
2011-03
期刊：
影响因子：
4.9
通讯作者：
H. Wan;Yongfei Bai;P. Schönbach;M. Gierus;F. Taube
中科院分区：
文献类型：
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作者：
H. Wan;Yongfei Bai;P. Schönbach;M. Gierus;F. Taube
为了寻求一种更可持续的放牧管理制度，在内蒙古半干旱草原上，提出了一种放牧和造草交替的混合管理制度，并与传统的管理制度(放牧或干草一致)进行了田间试验。从2005年到2009年连续5年，在不同的组织水平(即物种、植物功能群和群落)上，研究了地上生物量对两种放牧管理制度的响应。研究了这两种系统对羊草、大针茅、冰草、隐翅草等4种优势种种子生产潜力的影响。我们的结果表明，在传统系统中，放牧降低了各级组织的地上生物量。然而，在混合系统中，在所有组织水平上，生物量响应与放养率之间没有显著的负相关关系。降水波动对生物量响应有较强的影响，与传统系统相比，混合系统的生物量-降水关系斜率更高。这种效应可能归因于L的更积极的反应。中国人和A。降雨量增加。在传统系统中，放牧小区的生殖分蘖比例和密度均显著低于草场或非放牧对照小区。在混合系统中，无论上一生长季施加的放牧压力有多大，干草样地与未放牧对照样地之间均无显著差异。我们的研究结果表明，与传统系统相比，混合系统减轻了绵羊放牧引起的物种转移，并且往往对降水增加的反应更快。因此，用混合系统取代传统的放牧策略，将为内蒙古草原的土地可持续利用做出重要贡献。
Under the aim of searching for a more sustainable grazing management system, a mixed management system (grazing and haymaking alternate annually) was proposed and tested against traditional management system (used consistently either for grazing or haymaking) in the semiarid grassland of Inner Mongolia with a field manipulation experiment. The responses of aboveground biomass to the two grazing management systems were examined across different levels of organization (i.e., species, plant functional group, and community) and in five consecutive years from 2005 to 2009. The effects of the two systems on seed production potential of four dominant species (Leymus chinensis,Stipa grandis,Agropyron cristatum,Cleistogenes squarrosa) were also investigated. Our results demonstrate that, in the traditional system, aboveground biomass production across all the levels of organization was reduced by grazing. In mixed system, however, no significantly negative relationship between the biomass response and stocking rate was detected at all organization levels. Precipitation fluctuation had strong influence on biomass responses, and compared to the traditional system the slope of the biomass-precipitation relationship tends to be higher in the mixed system. This effect might be attributed to the more positive response ofL. chinensisandA. cristatumto increase in precipitation. In the traditional system, both the ratio and the density of reproductive tillers of the grazing subplots were significantly reduced compared to the haymaking or ungrazed control plots. In the mixed system, there was no significant difference between the haymaking subplots and the ungrazed control plots, regardless of the grazing pressures imposed on the haymaking subplots in the previous growing season. Our findings suggest that the mixed system mitigates the sheep grazing-induced species shift and it tends to be more responsive to increasing precipitation as compared to the traditional system. Therefore, replacement of the traditional grazing strategy with the mixed system could provide an important contribution to sustainable land-use of the Inner Mongolia grasslands.