Roisin Yves, Dejean Alain, Corbara Bruno, Orivel Jerôme, Samaniego Mirna, Leponce Maurice
Behavioural and Evolutionary Ecology, CP 160/12, Université Libre de Bruxelles, Avenue F.D. Roosevelt 50, 1050, Brussels, Belgium.
Oecologia. 2006 Aug;149(2):301-11. doi: 10.1007/s00442-006-0449-5. Epub 2006 Jun 22.
The importance of termites as decomposers in tropical forests has long been recognized. Studies on the richness and diversity of termite species and their ecological function have flourished in more recent times, but these have been mostly conducted in a thin stratum within a standing man's reach. Our aims were to evaluate the specific richness and composition of the termite assemblage in the canopy of a tropical rainforest and to determine its originality with respect to the sympatric ground-level fauna. We conducted systematic searches for canopy termites, together with conventional sampling of the sympatric ground-level fauna, in the San Lorenzo forest, Panama. We hypothesized that (1) the canopy accommodates two categories of wood-feeding termites (long-distance foragers and small-colony "one-piece" species) and possibly soil-feeders in suspended soil-like habitats; (2) due to the abundance of soil-feeders, the overall diversity of the ground fauna is higher than that of the canopy; (3) differences in microclimate and resource accessibility favour vertical stratification among wood-feeders. Sixty-three canopy samples yielded ten species of termites, all wood-feeders. Five of these were not found at ground level, although a total of 243 ground samples were collected, representing 29 species. In addition to long-distance foragers (Microcerotermes and Nasutitermes spp.) and small-colony termites (mostly Kalotermitidae), the canopy fauna included Termes hispaniolae, a wood-feeding Termitidae from an allegedly soil-feeding genus, living in large dead branches. Soil-feeders were absent from the canopy, probably because large epiphytes were scarce. As predicted, the ground fauna was much richer than that of the canopy, but the species richness of both habitats was similar when only wood-feeders were considered. Vertical stratification was strongly marked among wood-feeders, as all common species, apart from the arboreal-nesting Microcerotermes arboreus, could unequivocally be assigned to either a ground or a canopy group. The canopy, therefore, contributes significantly to the total species richness of the termite assemblage, and the diversity, abundance and ecological importance of canopy termites in tropical rainforests may be higher than previously recognized.
长期以来，白蚁作为热带森林中分解者的重要性已得到认可。近年来，关于白蚁物种丰富度和多样性及其生态功能的研究蓬勃发展，但这些研究大多是在一个人伸手可及的薄薄地层中进行的。我们的目标是评估热带雨林树冠层中白蚁群落的特定丰富度和组成，并确定其相对于同域地面动物群的独特性。我们在巴拿马的圣洛伦索森林中，对树冠层白蚁进行了系统搜索，并对同域地面动物群进行了常规采样。我们假设：（1）树冠层容纳两类以木材为食的白蚁（远距离觅食者和小群体“整体式”物种），以及可能在悬浮的类似土壤栖息地中的以土壤为食者；（2）由于以土壤为食者数量众多，地面动物群的总体多样性高于树冠层；（3）小气候和资源可获取性的差异有利于以木材为食者之间的垂直分层。63个树冠层样本产生了10种白蚁，均为以木材为食者。其中5种在地面未被发现，尽管总共收集了243个地面样本，代表29个物种。除了远距离觅食者（微角白蚁属和鼻白蚁属物种）和小群体白蚁（主要是木白蚁科）外，树冠层动物群还包括伊斯帕尼奥拉白蚁，一种来自据称以土壤为食的属的以木材为食的白蚁科，生活在大型枯枝中。树冠层中没有以土壤为食者，可能是因为大型附生植物稀少。正如预测那样，地面动物群比树冠层丰富得多，但仅考虑以木材为食者时，两个栖息地的物种丰富度相似。在以木材为食者中，垂直分层非常明显，因为除了树栖筑巢的树栖微角白蚁外，所有常见物种都可以明确地归为地面或树冠层群体。因此，树冠层对白蚁群落的总物种丰富度有显著贡献，热带雨林中树冠层白蚁的多样性、丰度和生态重要性可能比以前认识到的要高。
