Camarota Flávio, Powell Scott, S Melo Adriano, Priest Galen, J Marquis Robert, L Vasconcelos Heraldo
Instituto de Biologia Universidade Federal de Uberlândia Uberlândia Brazil; Department of Biological Sciences The George Washington University Washington DC USA.
Department of Biological Sciences The George Washington University Washington DC USA.
Ecol Evol. 2016 Nov 23;6(24):8907-8918. doi: 10.1002/ece3.2606. eCollection 2016 Dec.
A major goal of community ecology is to identify the patterns of species associations and the processes that shape them. Arboreal ants are extremely diverse and abundant, making them an interesting and valuable group for tackling this issue. Numerous studies have used observational data of species co-occurrence patterns to infer underlying assembly processes, but the complexity of these communities has resulted in few solid conclusions. This study takes advantage of an observational dataset that is unusually well-structured with respect to habitat attributes (tree species, tree sizes, and vegetation structure), to disentangle different factors influencing community organization. In particular, this study assesses the potential role of interspecific competition and habitat selection on the distribution patterns of an arboreal ant community by incorporating habitat attributes into the co-occurrence analyses. These findings are then contrasted against species traits, to explore functional explanations for the identified community patterns. We ran a suite of null models, first accounting only for the species incidence in the community and later incorporating habitat attributes in the null models. We performed analyses with all the species in the community and then with only the most common species using both a matrix-level approach and a pairwise-level approach. The co-occurrence patterns did not differ from randomness in the matrix-level approach accounting for all ant species in the community. However, a segregated pattern was detected for the most common ant species. Moreover, with the pairwise approach, we found a significant number of negative and positive pairs of species associations. Most of the segregated associations appear to be explained by competitive interactions between species, not habitat affiliations. This was supported by comparisons of species traits for significantly associated pairs. These results suggest that competition is the most important influence on the distribution patterns of arboreal ants within the focal community. Habitat attributes, in contrast, showed no significant influence on the matrix-wide results and affected only a few associations. In addition, the segregated pairs shared more biological characteristic in common than the aggregated and random ones.
群落生态学的一个主要目标是识别物种关联模式以及塑造这些模式的过程。树栖蚂蚁极其多样且数量众多，这使得它们成为解决这一问题的一个有趣且有价值的群体。众多研究利用物种共现模式的观测数据来推断潜在的组装过程，但这些群落的复杂性导致几乎没有确凿的结论。本研究利用了一个在栖息地属性（树种、树大小和植被结构）方面结构异常良好的观测数据集，以厘清影响群落组织的不同因素。具体而言，本研究通过将栖息地属性纳入共现分析，评估种间竞争和栖息地选择对树栖蚂蚁群落分布模式的潜在作用。然后将这些发现与物种特征进行对比，以探索对所识别的群落模式的功能解释。我们运行了一系列空模型，首先仅考虑群落中的物种出现情况，随后在空模型中纳入栖息地属性。我们对群落中的所有物种进行了分析，然后仅对最常见的物种使用矩阵层面方法和成对层面方法进行分析。在考虑群落中所有蚂蚁物种的矩阵层面方法中，共现模式与随机性并无差异。然而，对于最常见的蚂蚁物种检测到了一种隔离模式。此外，通过成对方法，我们发现了大量正负成对的物种关联。大多数隔离关联似乎是由物种间的竞争相互作用而非栖息地归属来解释的。这得到了显著关联对的物种特征比较的支持。这些结果表明，竞争是对焦点群落中树栖蚂蚁分布模式的最重要影响。相比之下，栖息地属性对整个矩阵结果没有显著影响，仅影响少数关联。此外，隔离对比聚集对和随机对共享更多的生物学特征。
