Long-term response of plant communities to herbivore exclusion at high elevation grasslands
Long-term response of plant communities to herbivore exclusion at high elevation grasslands
复制标题
高海拔草原植物群落对草食动物排斥的长期反应
DOI：
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发表时间：
2015
影响因子：
3.4
通讯作者：
María B. García
中科院分区：
文献类型：
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作者：
Iker Pardo;D. Doak;R. García;D. Gómez;María B. García
了解草食动物对植物群落的影响是预测放牧制度的变化将如何影响自然和半自然生态系统所必需的。突出的生态假说预测，草食动物的急剧减少，发生在许多欧洲山区，将引发快速的多样性损失和结构变化的草原，因为耐牧物种预计将迅速取代更高和更具竞争力的物种。本研究的目的是测试概括的草食动物的影响（主要是从低地）在高海拔草原生态相关的时间尺度，并解开气候条件的贡献，观察到的变化。物种丰富度，冠层高度，植物群落结构，生态群体之间的过渡概率进行了监测，在整个19年的食草动物排除和控制地块在中央比利牛斯山脉。我们使用排序分析来跟踪长期的社区响应草食动物排斥，和广义的添加剂模型来评估草食动物排斥和气候条件对测量变量的非线性影响。与预期相反，草食动物排除并没有显着影响物种丰富度，虽然冠层高度增加，它是不够激烈，以抑制不耐荫的物种。最强的植物群落结构和生态群体之间的过渡概率发生在一系列的温暖和干燥的生长季节，而在对照地块，这些变化较小，并在很大程度上逆转后，凉爽和潮湿的气候条件下返回。我们的研究结果表明，在高海拔草原放牧停止的长期影响可能比预测的要弱和慢。然而，这些影响可以与干燥和温暖的事件协同作用。因此，面对持续的气候变暖，维持过去的放牧活动可能是关键。
Understanding the effects of herbivores on plant communities is needed for anticipating how variation in grazing regimes will impact natural and semi-natural ecosystems. Prominent ecological hypotheses predict that drastic reductions of herbivory, as have occurred in many European mountains, will trigger fast diversity loss and structural changes in grasslands, because grazing tolerant species are expected to be rapidly replaced by taller and more competitive species. The aims of this study were to test generalizations of herbivory effects (mostly from lowlands) in high elevation grasslands over ecological relevant times scales, and to unravel the contribution of climatic conditions to observed changes. Species richness, canopy height, plant community structure, and transition probabilities among ecological groups were monitored throughout 19 years in herbivore exclusions and control plots in the Central Pyrenees. We used ordination analyses to track the long-term community response to herbivore exclusion, and generalized additive models to assess the non-linear effects of herbivore exclusion and climatic conditions on measured variables. Contrary to expectations, herbivore exclusion did not significantly affect species richness, and although canopy height increased, it was not drastic enough to suppress shade intolerant species. The strongest shifts in plant community structure and transition probabilities between ecological groups occurred during a sequence of warm and dry growing seasons, whereas in control plots, these changes were smaller, and largely reversed after cooler and wetter climatic conditions returned. Our results suggest that long-term effects of grazing cessation in high elevation grasslands can be weaker and slower than predicted. However, these effects can act synergistically with dry and warm events. Therefore, the maintenance of past grazing activities can be key in the face of ongoing climatic warming.