Tropical forests harbour significant proportion of global biodiversity. Recent studies are, however, reporting an increase in plant invasion and its effect on these forests. We surveyed three forest reserves in Ghana to determine how differences in invasion levels influence plant community structure. Species diversity and species richness, particularly pioneer and non-pioneer light demanders, decrease with increasing invasion level. There was no consistent pattern regarding the impact of different levels of invasion on the diversity of the different tree functional groups. Stand density of native trees were the same in two of the reserves whilst the basal area of the highly invaded sites was higher than that of the lightly invaded sites in two of the three reserves. Generally, while there are some patterns in diversity indices and functional groups that are broadly maintained across the three reserves, site-specificity was also important, with the direction of impact influenced by the type of species and habitats. The study adds to the growing body of evidence that ecological impacts of invasive species do not always increase proportionally with invader density but are complex and context-dependent. It also provides insights into silviculture and other forest management decision-making and interventions, with respect to invasive tree species in forest reserves.

热带森林拥有全球生物多样性的很大一部分。然而，最近的研究报道植物入侵及其对这些森林的影响有所增加。我们调查了加纳的三个森林保护区，以确定入侵程度的差异如何影响植物群落结构。物种多样性和物种丰富度，尤其是先驱和非先驱光需求者，随着入侵水平的提高而降低。关于不同入侵程度对不同树功能组多样性的影响，没有一致的模式。在两个保护区中，本地树木的林分密度相同，而在三个保护区中的两个中，高度入侵地区的基础面积高于轻度入侵地区。通常，尽管在这三个保护区中广泛保留着多样性指数和功能组的某些模式，但根据物种和栖息地的类型影响影响的方向，地点特异性也很重要。这项研究增加了越来越多的证据，即入侵物种的生态影响并不总是随入侵者的密度成比例地增加，而是复杂且取决于环境的。它还提供了关于森林保护区中入侵树木的造林和其他森林管理决策与干预措施的见解。这项研究增加了越来越多的证据，即入侵物种的生态影响并不总是随入侵者的密度成比例地增加，而是复杂且取决于环境的。它还提供了关于森林保护区中入侵树木的造林和其他森林管理决策与干预措施的见解。这项研究增加了越来越多的证据，即入侵物种的生态影响并不总是随入侵者的密度成比例地增加，而是复杂且取决于环境的。它还提供了关于森林保护区中入侵树木的造林和其他森林管理决策与干预措施的见解。