Ant mosaics occur in SE Asian oil palm plantation but not rain forest and are influenced by the presence of nest-sites and non-native species
Ant mosaics occur in SE Asian oil palm plantation but not rain forest and are influenced by the presence of nest-sites and non-native species
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DOI：
10.1111/j.1600-0587.2012.00192.x
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发表时间：
2013-09-01
期刊：
影响因子：
5.9
通讯作者：
Foster, William A.
中科院分区：
文献类型：
--
作者：
Fayle, Tom M.;Turner, Edgar C.;Foster, William A.
人为栖息地的改变可以极大地改变生物群落内的相互作用网络。蚂蚁是一个重要的生态群体，经常在受干扰的种植园栖息地中竞争性地相互作用，形成马赛克状的图案，其中优势物种形成相互排斥的领地。然而，这些蚂蚁镶嵌在原始森林中的存在是有争议的。在这里，我们使用物种共现的零模型评估了马来西亚沙巴州油棕种植园和原始雨林中蚂蚁竞争相互作用的相对优势。我们使用两个指标：C-score（衡量整体共现的平均程度）和一个新颖的指标 C-var-score（衡量共现程度的方差）。我们还通过从树冠和落叶微生境以及附生蕨类植物（树冠蚂蚁的重要巢穴）收集蚂蚁来研究巢穴的作用。此外，我们还评估了油棕种植园中广泛存在的非本地物种（出现 61 次，雨林中出现 5 次）是否对推动蚂蚁镶嵌的形成很重要。我们没有在任何原始森林微生境中发现蚂蚁镶嵌的证据。在油棕种植园中，附生植物中物种之间的隔离很明显，树冠的其余部分较弱，而落叶群落中则不存在。有趣的是，将非本地蚂蚁物种排除在分析之外增加了所有三个微生境中负面物种共现的程度，油棕冠层中的物种隔离变得具有统计学意义。我们的结果表明，非本地物种对种植园栖息地的入侵并不会导致蚂蚁群落中物种隔离的增加。相反，高度的物种隔离可能与冠层巢穴地点重要性的变化有关，在种植园中，群体对这些巢穴的竞争更加激烈。在原始森林中，较弱的巢穴限制和高度复杂、垂直分层、不均匀的树冠可能导致本文研究的蚂蚁物种之间随机共现。
Interaction networks within biotic communities can be dramatically altered by anthropogenic habitat modification. Ants, an important ecological group, often interact competitively to form mosaic-like patterns in disturbed plantation habitats, in which dominant species form mutually exclusive territories. However, the existence of these ant mosaics in pristine forests is contentious. Here we assess the relative strengths of ant competitive interactions in oil palm plantation and primary rain forest in Sabah, Malaysia, using null models of species co-occurrence. We use two metrics: the C-score, which measures mean degree of overall co-occurrence, and a novel metric, the C-var-score, which measures the variance in degree of co-occurrence. We also investigate the role of nest sites by collecting ants from canopy and leaf litter microhabitats, and from epiphytic ferns, an important nest site for canopy ants. Furthermore, we assess whether non-native species, which were widespread in oil palm plantation (61 occurrences vs five in rain forest) are important in driving the formation of ant mosaics. We found no evidence for ant mosaics in any primary forest microhabitat. In oil palm plantation, segregation between species was pronounced in epiphytes, weak in the rest of the canopy and absent in leaf litter communities. Intriguingly, exclusion of non-native ant species from analyses increased the degree of negative species co-occurrence in all three microhabitats, with species segregation in the oil palm canopy becoming statistically significant. Our results suggest that invasion of plantation habitats by non-native species does not drive increased species segregation in ant communities. Rather, high degrees of species segregation might relate to changes in the importance of canopy nest sites, with colonies competing more strongly for these in plantations. In primary forests, weaker nest-site limitation and the highly complex, more vertically stratified, non-uniform canopy could lead to random co-occurrence between ant species at the scales studied here.