Ants as indicators of environmental change and ecosystem processes
Ants as indicators of environmental change and ecosystem processes
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DOI：
10.1016/j.ecolind.2017.01.029
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发表时间：
2017-12
影响因子：
6.9
通讯作者：
Yvonne Tiede;J. Schlautmann;D. Donoso;Christine I. B. Wallis;J. Bendix;R. Brandl;N. Farwig
中科院分区：
文献类型：
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作者：
Yvonne Tiede;J. Schlautmann;D. Donoso;Christine I. B. Wallis;J. Bendix;R. Brandl;N. Farwig
环境压力和土地利用的变化导致了物种迅速而剧烈的丧失。因此，我们需要有效的监测计划，不仅提醒我们生物多样性的丧失，还提醒我们物种组合和相关生态系统过程的功能变化。蚂蚁是陆地食物网的重要组成部分，也是食物网相互作用和众多生态系统过程中的关键群体。它们对环境变化的敏感和快速反应表明它们是监测非生物、生物和功能变化的合适指标组。我们测试了蚂蚁的发生率（即 30 个诱饵下所有物种发生率的总和）、物种丰富度和功能丰富度作为对环境变化、森林退化和草食节肢动物的生态系统过程捕食的生态响应指标的适宜性。我们在厄瓜多尔南部的山地雨林中沿海拔梯度（1000-3000 米）和跨季节（湿润期和干燥期）采样数据。蚂蚁的发生率随着海拔的升高而下降，但不随森林退化而变化。旱季蚂蚁发病率更高。物种丰富度与发病率高度相关，并显示出可比的结果。功能丰富度也随着海拔的升高而下降，但不随森林退化而改变。然而，零模型比较表明，功能丰富度模式与具有跨物种随机分布的性状集的蚂蚁组合的预期模式没有差异。人工毛毛虫的捕食量沿海拔梯度下降；这种模式并不是由海拔本身驱动的，而是由蚂蚁的发生率（或者可以与蚂蚁的丰富度互换）驱动的，这对捕食产生了积极的影响。尽管蚂蚁发生率（或蚂蚁丰富度）较低，但在潮湿季节，捕食量较高，并且不会随着森林退化和蚂蚁功能丰富度而改变。我们使用路径分析来理清环境因素温度（以海拔为代表）、季节和栖息地退化与蚂蚁的发生率和功能丰富度及其对捕食的影响的因果关系。我们的结果表明，预测的全球变暖可能会支持更活跃和物种丰富的蚂蚁群落，这反过来又会增加对草食节肢动物的捕食。然而，这一预测应该有所保留，因为它假设蚂蚁的扩散与气候变化保持同步，以及蚂蚁与食物网中的捕食之间的一维关系，其中包括复杂得多的物种相互作用。我们的研究结果还表明，我们研究区域的退化森林可能为表层、地面栖息的蚂蚁群落提供了合适的栖息地，这些群落在发生率、物种丰富度、功能丰富度、组成或对来自原始森林群落的节肢动物的捕食方面没有差异。最重要的是，我们的结果表明，蚂蚁的出现和活动是生态系统过程的重要驱动因素，蚂蚁的发生率和丰富度的变化可以用作对温度变化和巨型多样化森林生态系统中的捕食反应的有效指标。
Environmental stressors and changes in land use have led to rapid and dramatic species losses. As such, we need effective monitoring programs that alert us not only to biodiversity losses, but also to functional changes in species assemblages and associated ecosystem processes. Ants are important components of terrestrial food webs and a key group in food web interactions and numerous ecosystem processes. Their sensitive and rapid response to environmental changes suggests that they are a suitable indicator group for the monitoring of abiotic, biotic, and functional changes. We tested the suitability of the incidence (i.e. the sum of all species occurrences at 30 baits), species richness, and functional richness of ants as indicators of ecological responses to environmental change, forest degradation, and of the ecosystem process predation on herbivorous arthropods. We sampled data along an elevational gradient (1000–3000 m a.s.l.) and across seasons (wetter and drier period) in a montane rainforest in southern Ecuador. The incidence of ants declined with increasing elevation but did not change with forest degradation. Ant incidence was higher during the drier season. Species richness was highly correlated with incidence and showed comparable results. Functional richness also declined with increasing elevation and did not change with forest degradation. However, a null-model comparison revealed that the functional richness pattern did not differ from a pattern expected for ant assemblages with randomly distributed sets of traits across species. Predation on artificial caterpillars decreased along the elevational gradient; the pattern was not driven by elevation itself, but by ant incidence (or interchangeable by ant richness), which positively affected predation. In spite of lower ant incidence (or ant richness), predation was higher during the wetter season and did not change with forest degradation and ant functional richness. We used path analysis to disentangle the causal relationships of the environmental factors temperature (with elevation as a proxy), season, and habitat degradation with the incidence and functional richness of ants, and their consequences for predation. Our results would suggest that the forecasted global warming might support more active and species-rich ant assemblages, which in turn would mediate increased predation on herbivorous arthropods. However, this prediction should be made with reservation, as it assumes that the dispersal of ants keeps pace with the climatic changes as well as a one-dimensional relationship between ants and predation within a food-web that comprises species interactions of much higher complexity. Our results also suggested that degraded forests in our study area might provide suitable habitat for epigaeic, ground-dwelling ant assemblages that do not differ in incidence, species richness, functional richness, composition, or predation on arthropods from assemblages of primary forests. Most importantly, our results suggest that the occurrence and activity of ants are important drivers of ecosystem processes and that changes in the incidence and richness of ants can be used as effective indicators of responses to temperature changes and of predation within mega-diverse forest ecosystems.