Pérez-Sánchez A J, Lattke J E, Viloria A L
Lab de Biología de Organismos, Centro de Ecología, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Venezuela.
Neotrop Entomol. 2013 Apr;42(2):128-36. doi: 10.1007/s13744-012-0096-y. Epub 2012 Dec 21.
In xeric ecosystems, ant diversity response to aridity varies with rainfall magnitude and gradient extension. At a local scale and with low precipitation regimes, increased aridity leads to a reduction of species richness and an increased relative abundance for some ant species. In order to test this pattern in tropical environments, ant richness and relative abundance variation were evaluated along 35 km of an aridity gradient in the Araya Peninsula, state of Sucre, Venezuela. Three sampling stations comprising five transects each were set up. Pitfall traps and direct collecting from vegetation were assessed per transect. Overall, 52 species, 23 genera, and 7 subfamilies of ants were recorded in the peninsula. The total number of species and genera recorded by both sampling stations and transects decreased linearly with increasing aridity. Total relative abundance was highest in the most arid portion of the peninsula, with Crematogaster rochai (Forel) and Camponotus conspicuus zonatus (Emery) (Hymenoptera: Formicidae) being the numerically dominant species. Spatial and multivariate analyses revealed significant changes in ant composition every 11 km of distance, and showed a decrease of ant diversity with the increase of harsh conditions in the gradient. Here, we discuss how local geographic and topographic features of Araya originate the aridity gradient and so affect the microhabitat conditions for the ant fauna.
在干旱生态系统中，蚂蚁多样性对干旱的响应随降雨量大小和梯度延伸而变化。在局部尺度且降水较少的情况下，干旱加剧会导致物种丰富度降低，一些蚂蚁物种的相对丰度增加。为了在热带环境中验证这一模式，沿着委内瑞拉苏克雷州阿拉亚半岛35公里的干旱梯度，对蚂蚁丰富度和相对丰度的变化进行了评估。设置了三个采样站，每个采样站包含五条样带。对每个样带评估了陷阱诱捕法和从植被上直接采集的方法。在该半岛共记录到52种、23属和7个亚科的蚂蚁。采样站和样带记录的物种和属的总数随干旱加剧呈线性下降。总相对丰度在半岛最干旱的部分最高，罗氏举腹蚁（Forel）和显著弓背蚁分区亚种（Emery）（膜翅目：蚁科）是数量上占优势的物种。空间分析和多变量分析表明，每相隔11公里蚂蚁组成就会发生显著变化，并且随着梯度中恶劣条件的增加，蚂蚁多样性降低。在此，我们讨论阿拉亚半岛的局部地理和地形特征如何形成干旱梯度，进而影响蚂蚁动物群的微生境条件。
