Data from: Niche differentiation in rainforest ant communities across three continents

A central prediction of niche theory is that biotic communities are structured by niche differentiation arising from competition. To date, there have been numerous studies of niche differentiation in local ant communities, but, little attention has been given to the macroecology of niche differentiation, including the extent to which particular biomes show distinctive patterns of niche structure across their global ranges. We investigated patterns of niche differentiation and competition in ant communities in tropical rainforests, using different baits reflecting the natural food spectrum. We examined the extent of temporal and dietary niche differentiation and spatial segregation of ant communities at five rainforest sites in the neotropics, paleotropics, and tropical Australia. Despite high niche overlap, we found significant dietary and temporal niche differentiation in every site. However, there was no spatial segregation among foraging ants at the community level, despite strong competition for preferred food resources. Although sucrose, melezitose, and dead insects attracted most ants, some species preferentially foraged on seeds, living insects or bird feces. Moreover, most sites harboured more diurnal than nocturnal species. Overall niche differentiation was strongest in the least diverse site, possibly due to its lower number of rare species. Both temporal and dietary differentiation thus had strong effects on the ant assemblages, but their relative importance varied markedly among sites. Our analyses show that patterns of niche differentiation in ant communities are highly idiosyncratic even within a biome, such that a mechanistic understanding of the drivers of niche structure in ant communities remains elusive.

生态位（niche）理论的核心预测之一为：生物群落由竞争驱动的生态位分化所塑造。迄今为止，针对局地蚂蚁群落的生态位分化研究已为数不少，但针对生态位分化的宏观生态学研究却寥寥无几，例如特定生物群区在全球分布范围内是否呈现独特的生态位结构模式等议题尚未得到充分关注。本研究以热带雨林蚂蚁群落为研究对象，采用能够反映蚂蚁天然食物谱的多种诱饵，探究其生态位分化与种间竞争模式。我们在新热带区、古热带区以及澳大利亚热带地区的5处雨林样地中，调查了蚂蚁群落在时间、食物资源维度的生态位分化程度，以及空间分隔情况。尽管各站点的生态位重叠度普遍较高，但我们在所有样地中均检测到了显著的食物资源与时间维度的生态位分化。然而，尽管蚂蚁类群间对优质食物资源存在激烈竞争，但在群落尺度上并未观测到觅食蚂蚁的空间分隔现象。尽管蔗糖（sucrose）、松三糖（melezitose）与死虫能够吸引绝大多数蚂蚁，但部分物种会优先取食种子、活虫或鸟类粪便。此外，多数样地中的昼行性蚂蚁物种数量多于夜行性物种。整体而言，物种多样性最低的样地的生态位分化程度最高，这可能与其稀有物种数量更少有关。因此，时间与食物资源维度的生态位分化均对蚂蚁群落集合产生了显著影响，但二者的相对重要性在不同样地间存在显著差异。本研究的分析结果表明，即便在同一生物群区内，蚂蚁群落的生态位分化模式也存在极强的特异性，因此目前仍难以从机制层面阐释蚂蚁群落生态位结构的驱动因素。