Floren Andreas, Müller Tobias
Department of Bioinformatics, Biocentre, University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
Department of Animal Ecology and Tropical Biology, Biocentre, University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
Animals (Basel). 2025 Jun 28;15(13):1914. doi: 10.3390/ani15131914.
Ants are key drivers of biodiversity in both tropical and temperate forests, though the underlying mechanisms of this remain debated. In tropical lowland rainforests, ants dominate the canopy as opportunistic predators, shaping arthropod abundance and community structure. By contrast, few arboreal ant species exist in temperate forests due to climatic constraints, and predation pressure is generally low. This changes when ground-nesting species enter the canopy to forage. Using insecticidal knockdown, we collected arthropod communities from trees with high and low ant abundance in both tropical and temperate forests and in different seasons. We found consistently higher arthropod abundances on trees with strong ant dominance, including preferred prey taxa such as Diptera, Psocoptera, and Lepidoptera. In temperate forests, high arthropod densities may be driven by aphid-produced honeydew, whereas in tropical rainforests, the absence of large hemipteran aggregations suggests that other mechanisms are involved. Consequently, this mechanism fails to explain high arthropod abundance in tropical primary forests. In contrast, secondary tropical forests host structurally and compositionally altered ant communities, resulting in reduced predation pressure and a marked increase in the abundance of individual species, including potential pest species. These findings suggest that biodiversity maintenance in the canopy depends on intact, diverse ant communities. Recolonization from nearby primary forests is essential for recovery, yet even after five decades, secondary forests remain ecologically distinct, rendering full restoration to primary forest conditions unlikely within a management-relevant timeframe.
蚂蚁是热带和温带森林生物多样性的关键驱动因素，尽管其背后的机制仍存在争议。在热带低地雨林中，蚂蚁作为机会主义捕食者主导着树冠层，塑造着节肢动物的数量和群落结构。相比之下，由于气候限制，温带森林中树栖蚂蚁物种很少，捕食压力通常较低。当地面筑巢物种进入树冠层觅食时，这种情况就会改变。我们使用杀虫剂击倒法，在热带和温带森林的不同季节，从蚂蚁数量多和少的树上收集节肢动物群落。我们发现，在蚂蚁占主导地位的树上，节肢动物的数量一直较高，包括双翅目、啮目和鳞翅目等偏好的猎物类群。在温带森林中，高节肢动物密度可能是由蚜虫产生的蜜露驱动的，而在热带雨林中，没有大型半翅目聚集表明涉及其他机制。因此，这种机制无法解释热带原始森林中节肢动物的高丰度。相比之下，次生热带森林拥有结构和组成发生改变的蚂蚁群落，导致捕食压力降低，个别物种的丰度显著增加，包括潜在的害虫物种。这些发现表明，树冠层生物多样性的维持依赖于完整、多样的蚂蚁群落。从附近原始森林重新定殖对于恢复至关重要，但即使经过五十年，次生森林在生态上仍然不同，在与管理相关的时间范围内不太可能完全恢复到原始森林状态。
