Hotspot areas of marine introduced species in the Southwestern Atlantic

Some worldwide marine regions have been invaded by introduced species more than others, and those accruing a large number of introduced species are identified as hotspot areas. The southern Southwest Atlantic (SWA) is a vast region that has a variety of heterogeneous environments that are affected by different environmental and anthropogenic drivers and have been colonized by many introduced species. Nevertheless, a comprehensive analysis considering all these aspects together to identify hotspots of introduced species has not been developed, nor has a statistically based procedure to define and identify these hotspots been produced. Therefore, the main objectives of this study were to (1) quantify the spatial richness of introduced species (ISR) in the SWA, (2) identify introduced species hotspots, (3) explore the environmental and anthropogenic drivers that explain the ISR pattern and the assemblage composition of introduced species in these hotspots, and (4) assess the variation in the assemblage species composition among the introduced species in the identified hotspots. Six different hotspots were identified. The ISR in these hotspots was significantly explained by a set of environmental (maximum and minimum sea surface temperature, distance to shore, maximum salinity) and anthropogenic drivers (maritime traffic density, distance to the nearest port). Assemblage composition was related only to the environmental predictors. The variation in assemblage composition showed heterogeneity among introduced species hotspots. Our study shows that mapping introduced species hotspots and identifying them through spatial statistics facilitates the synthesis and integration of information objectively. This represents a cutting-edge approach to prioritize areas for management and adopt policies for the SWA.