Data from: Logging, exotic plant invasions, and native plant reassembly in a lowland tropical rain forest

Habitat modification and biological invasions are key drivers of global environmental change. However, the extent and impact of exotic plant invasions in modified tropical landscapes remains poorly understood. We examined whether logging drives exotic plant invasions, and whether their combined influences alter understory plant community composition in lowland rain forests in Borneo. We tested the relationship between understory communities and local- and landscape-scale logging intensity, using leaf area index (LAI) and above-ground biomass (AGB) data from 192 plots across a logging-intensity gradient from primary to repeatedly-logged forests. Overall, we found relatively low levels of exotic plant invasions, despite an intensive logging history. Exotic species were more speciose, had greater cover, and more biomass in sites with more local-scale canopy loss. Surprisingly, though, exotic species invasion was not related to either landscape-scale canopy loss nor road configuration. Moreover, logging and invasion did not seem to be acting synergistically on native plant composition, except that seedlings of the canopy-dominant Dipterocarpaceae family were less abundant in areas with higher exotic plant biomass. Current low levels of invasion, and limited association with native understory community change, suggest there is a window of opportunity to manage invasive impacts. We caution about potential lag effects and the possibly severe negative impacts of exotic plant invasions on the long-term quality of tropical forest, particularly where agricultural plantations function as permanent seed sources for recurrent dispersal along logging roads. We therefore urge prioritization of strategic management plans to counter the growing threat of exotic plant invasions in modified tropical landscapes.

生境改造与生物入侵是全球环境变化的核心驱动因素。然而，人类改造后的热带景观中，外来植物入侵的范围与影响目前仍鲜为人知。本研究以婆罗洲低地雨林为研究对象，探讨了采伐是否会加剧外来植物入侵，以及二者的共同作用是否会改变林下植物群落组成。本研究利用沿采伐强度梯度（从原生林到多次采伐林）的192块样地的叶面积指数（Leaf Area Index, LAI）与地上生物量（Above-ground Biomass, AGB）数据，分析了林下群落与局地尺度及景观尺度采伐强度之间的关联。尽管研究区域存在高强度采伐历史，但整体而言外来植物入侵水平相对较低。在局地冠层损失更严重的样地中，外来物种的丰富度更高、盖度更大、生物量也更多。但令人意外的是，外来植物入侵与景观尺度冠层损失及道路布局均无显著关联。此外，采伐与入侵并未对本土植物群落组成产生协同影响，仅在外来植物生物量较高的区域，冠层优势类群龙脑香科（Dipterocarpaceae）的幼苗丰度有所降低。当前较低的入侵水平，以及其与本土林下群落变化的有限关联，表明我们仍有管控入侵影响的窗口期。我们需警惕潜在的滞后效应，以及外来植物入侵对热带森林长期质量可能造成的严重负面影响——尤其是在人工种植园可作为永久性种源，通过采伐道路持续扩散的区域。因此，我们呼吁优先制定战略性管理方案，以应对改造后热带景观中外来植物入侵日益严峻的威胁。