The impacts of grazing and rainfall variability on the dynamics of a Sahelian rangeland
The impacts of grazing and rainfall variability on the dynamics of a Sahelian rangeland
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DOI：
10.1016/j.jaridenv.2005.06.014
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发表时间：
2006-02-01
影响因子：
2.7
通讯作者：
Hein, L
中科院分区：
文献类型：
--
作者：
Hein, L
放牧压力和降雨变化对牧场动态的影响一直是争论的话题。了解这两个因素的综合影响对于制定牧场的有效管理战略至关重要。在本文中，放牧和降雨量的变化对动态的萨赫勒牧场在北方塞内加尔的影响进行了研究。具体而言，本文评估其综合影响的物种组成，地上植物量生产和雨水利用效率（芸香）的基础上，10年（1981-1990年）放牧实验进行的Widou Thiengoly集水区的费洛，北方塞内加尔。实验包括高（0.15-0.20 TLU ha（-1），对应于当前放牧）和中等（0.10 TLU ha（-1））放牧压力。结果表明，这两个放牧制度的物种组成，地上植物量生产和芸香显着不同，这种差异是最明显的年降雨量低。在干旱年份，地上植物量生产和芸香显着减少的地块受到高放牧压力。因此，高放牧压力对生产力的费罗的影响几乎没有注意到在正常或高于正常降雨量的年份，但牧场的生产力在干旱期间受到强烈影响。这些研究结果对牧场的管理具有重要意义;它们表明，放牧压力大可能会增加牧场生态系统和当地人民对干旱的脆弱性。(c)2005 Elsevier Ltd.保留所有权利。
The impacts of grazing pressure and rainfall variability on rangeland dynamics have been the topic of much debate. Understanding the combined impact of these two factors is crucial for the development of efficient management strategies for rangelands. In this paper, the impacts of grazing and rainfall variability on the dynamics of a Sahelian rangeland in Northern Senegal are examined. Specifically, the paper assesses their combined impact on species composition, above-ground phytomass production and rain-use efficiency (RUE), on the basis of a 10-year (1981-1990) grazing experiment conducted in the Widou-Thiengoly catchment in the Ferlo, Northern Senegal. The experiment included both a high (0.15-0.20 TLU ha(-1), corresponding to current grazing) and a medium (0.10 TLU ha(-1)) grazing pressure. It is shown that species composition, above-ground phytomass production and RUE markedly differ for these two grazing regimes-and that the differences are most pronounced in years with low rainfall. In dry years, both above-ground phytomass production and RUE are significantly reduced in the plots subject to a high grazing pressure. Consequently, the impacts of high grazing pressures on the productivity of the Ferlo are hardly noticed during years with normal or above normal rainfall, but the rangeland's productivity is strongly affected during a drought. The findings have important implications for the management of rangelands; they indicate that high grazing pressures may increase the vulnerability of rangeland ecosystems and local people to droughts. (c) 2005 Elsevier Ltd. All rights reserved.