The Effects of Invasive Species on the Decline in Species Richness

Abstract

Abstract Biological invasions are one of the most important ecological disturbances that threaten native biodiversity. An expected increase in the rate of species extinction will have major effects on the structure and function of ecosystems worldwide. The goal of our study is to determine which ecological properties mediate the impact of invasive species on biodiversity loss on a global scale using a meta-analysis. We considered the role of properties such as the trophic and taxonomic position of invaders, taxonomic groups of invaded systems, the type of habitats invaded and whether the invasive species is included in a list of the most harmful invasive species for biodiversity loss. We compiled 185 studies that included 253 numerical values of changes of species richness due to species invasion. We investigated the role of trophic and taxonomic parameters of invaders, as well as the role of abiotic parameters of habitat on changes in species richness due to biological invasions. Our results show that plant invaders are highly represented (85% of all invaders studied), especially those belonging to the Poaceae family. For animals, predation seems to be the feeding behaviour associated with the greatest decrease in species richness and this relationship is independent of habitat type, with a 21% decline observed in aquatic habitats and a 27% decline in terrestrial habitats. In invaded communities, birds suffer the greatest decline in species richness (41% decline). Finally, we found that species richness declines in Europe are spatially autocorrelated, suggesting that the consequences of invasive species cannot be understood through local-scale analysis alone.