This experimental field study provides first insights into the impact of a widely spread non-native fish species, round goby Neogobius melanostomus (Pallas 1814), on the diversity of native epifaunal macroinvertebrate communities in the Baltic Sea. A cage experiment was conducted in a macrophyte habitat in the Åland islands located in the northern Baltic Sea. Round gobies (13.5 ± 0.8 cm) affected macroinvertebrate biodiversity from a taxonomic and a trait-based point of view. Specifically, round goby decreased overall abundance, biomass and taxon richness of epifaunal invertebrates. Additionally, taxonomic and trait-based composition were affected, as the gobies reduced abundances of common bivalve (Cerastoderma spp. and Mytilus sp.) and gastropod species (Hydrobia spp.), and thereby modified the relative trait composition of the invertebrate assemblages. Round gobies consumed mainly larger epifaunal individuals leading to an overall decrease in invertebrate body size. Such alterations in taxonomic and trait-based diversity and composition of invertebrate communities through round goby predation may have implications for native fish species and other trophic levels in the respective food webs through food competition and trophic cascades. Round gobies might therefore affect ecosystem processes in invaded areas, and thus influence ecosystem functioning and services.

这项实验性野外研究提供了关于广泛传播的非本地鱼类（虾虎鱼Neogobius melanostomus（Pallas 1814））对波罗​​的海本地表生真菌无脊椎动物群落多样性的影响的初步见解。在波罗的海北部的奥兰群岛的大型植物栖息地中进行了笼养实验。从分类学和基于特征的角度来看，圆形虎虾（13.5±0.8厘米）会影响大型无脊椎动物的生物多样性。具体而言，轮虾降低了表皮无脊椎动物的总体丰度，生物量和分类生物的丰富性。此外，由于虾虎鱼减少了常见双壳类动物（Cerastoderma spp。和Mytilus sp。）和腹足动物的种类（分类），因此分类和基于特征的组成也受到影响。Hydrobia spp。），从而改变了无脊椎动物组合的相对性状组成。轮状虾虎鱼主要消耗较大的表生动物，导致无脊椎动物的体型总体下降。通过虾虎鱼的捕食，无脊椎动物群落的分类学和基于特征的多样性以及组成的这种变化，可能通过食物竞争和营养级联作用对各自食物网中的本地鱼类物种和其他营养水平产生影响。因此，轮状虾虎鱼可能会影响被入侵地区的生态系统过程，从而影响生态系统的功能和服务。