Invasive species are a major threat to biodiversity and ecosystem function. Thus, understanding their spread and ecological impacts is critical for management and control. Strawberry guava (Psidium cattleianum Sabine) is an aggressive invader across the tropics and has been rapidly spreading throughout the eastern rainforests of Madagascar. However, both the mechanisms of its spread on the island and the consequences of its invasion on native floral and faunal communities remain largely unexplored. By surveying multiple sites across Madagascar’s eastern rainforests, we demonstrate that the introduction of P. cattleianum significantly correlates with changes in forest structure—namely tree/shrub size, taxonomic richness, and taxonomic diversity. Further, at a local scale, the presence of P. cattleianum was associated with an increase in frugivore species richness; its primary dispersers during our study period were lemurs. Moreover, we identified species-specific effects of lemur gut-passage on the germination of P. cattleianum seeds. Finally, microsatellite analysis of P. cattleianum from a variety of locations across Madagascar demonstrated three distinct, highly differentiated, genetic population clusters, each with high levels of intra-population diversity, suggesting multiple independent introductions of P. cattleianum into Madagascar followed by long-distance dispersal. Collectively, these findings illuminate the complex status of strawberry guava invasion in Madagascar, which poses a growing threat to the island’s unique flora and yet provides important forage for threatened and charismatic animal species.

入侵物种是对生物多样性和生态系统功能的主要威胁。因此，了解它们的扩散和生态影响对于管理和控制至关重要。草莓番石榴（Psidium cowianum Sabine）是热带地区的侵略性入侵者，已在马达加斯加的东部雨林中迅速传播。然而，无论是其在岛上的传播机制，还是其入侵对本地花卉和动物群落的后果，在很大程度上仍未得到开发。通过对马达加斯加东部雨林的多个地点进行调查，我们证明了引入了P. cowianum与森林结构的变化（即树木/灌木大小，生物分类丰富度和生物分类多样性）显着相关。此外，在地方范围内，P。cowianum的存在与节食物种丰富度的增加有关。在我们研究期间，其主要分散剂是狐猴。此外，我们确定了狐猴肠道通道对P. cowianum种子萌发的物种特异性影响。最后，对马达加斯加各地不同地点的牛瘟进行微卫星分析，结果显示了三个截然不同，高度分化的遗传种群群，每个种群内部种群多样性水平高，表明牛瘟的多次独立引入进入马达加斯加，然后进行长途疏散。这些发现共同说明了马达加斯加草莓番石榴入侵的复杂情况，这对该岛独特的植物群构成了越来越大的威胁，但为受到威胁和具有超凡魅力的动物提供了重要的饲料。