Rangeland management in highly variable environments : Resource variations across the landscape mediate the impact of grazing on vegetation in
Rangeland management in highly variable environments : Resource variations across the landscape mediate the impact of grazing on vegetation in
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高度变化环境中的牧场管理：整个景观的资源变化调节放牧对植被的影响
DOI：
10.1111/grs.12008
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发表时间：
2013
影响因子：
1.3
通讯作者：
T. Sasaki and T. Okuro
中科院分区：
文献类型：
--
作者：
Kakinuma;K.;T. Okayasu;T. Sasaki and T. Okuro
在随机降雨情况下评估放牧引起的干旱和半干旱牧场的退化具有挑战性。为了评估高度变化的环境下放牧对植被的影响，我们重点关注与当地牧场利用规模相关的资源变化。具体来说，我们测试了这样一个假设：在干旱期间大量使用的地区（即关键资源区）放牧对资源的影响比其他地方更大。在蒙古曼达戈壁附近，我们根据景观类型在四种典型植被群落（锦鸡儿、葱属、芨芨草和红砂）中建立了研究地点。首先，我们采访了四种社区类型的主要知情人，以研究当地牧民在正常夏季和干旱夏季如何使用这些社区。其次，我们比较了社区之间的粪便颗粒数量，以量化不同放牧对每个社区的影响。最后，为了确定放牧对每个社区植被的影响，我们对每个地点的放牧和非放牧地块进行了植被调查。据受访者称，在正常夏季，各种类型的群落都会被使用，但在干旱期间，主要使用的群落是芨芨草群落。芨芨草群落中粪便颗粒的数量最多。芨芨草和红砂群落中的物种组成受放牧的影响明显大于其他群落。这些结果表明芨芨草群落将在研究地点发挥关键资源的作用，放牧影响影响关键资源区。如果牧场管理仅侧重于维持资源的可及性，那么即使在高度变化的牧场上，放牧引起的关键资源区域的退化也可能发生。
Assessment of grazing‐induced degradation of arid and semiarid rangelands with stochastic rainfall regimes is challenging. To assess grazing impacts on vegetation under highly variable environments, we focused on resource variations in relation to the scale of local rangeland use. Specifically, we tested the hypothesis that grazing impacts on resources were greater in areas heavily used during drought (i.e. key resource areas) than elsewhere. Near Mandalgobi, Mongolia, we established study sites in four typical vegetation communities (Caragana, Allium,AchnatherumandReaumuria) according to landscape type. First, we interviewed key informants about the four community types to examine how local pastoralists used these communities during normal and drought summers. Second, we compared dung pellets numbers among communities to quantify the different grazing impacts on each community. Finally, to determine grazing impacts on vegetation in each community, we performed vegetation surveys in grazing and non‐grazing plots at each site. According to respondents, during normal summers all types of community were used, but during drought, the main community used wasAchnatherumcommunity. The number of dung pellets was highest in theAchnatherumcommunity. Species composition was significantly more affected by grazing in theAchnatherumandReaumuriacommunity than in the other communities. These results suggested that theAchnathrumcommunity would have a role of key resource in study sites and grazing impacts affected key resource areas. If rangeland management is focused only on maintaining resource accessibility, then grazing‐induced degradation of key resource areas could occur even on highly variable rangelands.