Woody encroachment affects multiple dimensions of ant diversity in a neotropical savanna
Woody encroachment affects multiple dimensions of ant diversity in a neotropical savanna
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DOI：
10.1111/icad.12633
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发表时间：
2021-12
影响因子：
3.5
通讯作者：
Karen C. Neves;Bernardo Santos;T. Schultz;D. Gotzek;R. C. Abreu;G. Durigan;H. Vasconcelos
中科院分区：
文献类型：
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作者：
Karen C. Neves;Bernardo Santos;T. Schultz;D. Gotzek;R. C. Abreu;G. Durigan;H. Vasconcelos
尽管热带稀树草原树木入侵已成为一种全球现象，但人们对其在多个维度和水平上对热带稀树草原生物多样性的影响知之甚少。结合野外调查、物种水平的系统发育和形态学数据集的功能指标，我们评估了森林覆盖的逐渐增加对热带草原景观中新热带蚂蚁群落的分类、功能和系统发育多样性的影响，包括α和β水平。蚂蚁沿着广泛的树木覆盖梯度进行采样，从开放的热带稀树草原到在原热带稀树草原地区建立的森林。在α水平上，树木覆盖变化对蚂蚁群落的分类和功能多样性有显著影响，但对系统发育多样性没有影响。总体而言，蚂蚁群落对树木覆盖度变化的响应在很大程度上是非线性的，因为在热带稀树草原/森林过渡阶段，群落的分类多样性、功能和系统发育组成的差异往往比梯度的其他部分更强烈。这表明，一旦稀树草原变成森林，稀树草原蚂蚁群落就会迅速切换到另一种状态。新形成的森林地区的蚂蚁群落缺乏许多稀树草原栖息地的典型物种，这表明维持灭火政策可能导致蚂蚁多样性减少，并在景观尺度上导致蚂蚁动物群的同质化。
Although savanna woody encroachment has become a global phenomenon, relatively little is known about its effects on multiple dimensions and levels of savanna biodiversity. Using a combination of field surveys, a species‐level phylogeny, and functional metrics drawn from a morphological dataset, we evaluated how the progressive increase in tree cover in a fire‐suppressed savanna landscape affects the taxonomic, functional, and phylogenetic diversity of neotropical ant communities, at both the alpha and beta levels. Ants were sampled along an extensive tree cover gradient, ranging from open savannas to forests established in former savanna areas. Variation in tree cover had a significant influence on all facets of diversity at the beta level, whereas at the alpha level tree cover variation affected the taxonomic and functional but not the phylogenetic diversity of the ant communities. In general, ant community responses to variation in tree cover were largely non‐linear as differences in taxonomic alpha diversity and in the taxonomic, functional, and phylogenetic composition of the sampled communities were often much stronger at the savanna/forest transition than at any other part of the gradient. This indicates that savanna ant communities switch rapidly to an alternative state once the savanna turns into forest. Ant communities in the newly formed forest areas lacked many of the species typical of the savanna habitats, suggesting that the maintenance of a fire suppression policy is likely to result in a decrease in ant diversity and in the homogenisation of the ant fauna at the landscape scale.