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Aim: Human activities have introduced numerous non‐native species (NNS) worldwide. Understanding and predicting large‐scale NNS establishment patterns remain fundamental scientific challenges. Here, we evaluate if NNS composition represents a proportional subset of the total species pool available to invade (i.e. total global biodiversity), or, conversely, certain taxa are disproportionately pre‐disposed to establish in non‐native areas. Location: Global. Time period: Present day. Major taxa studied: Global diversity. Methods: We compiled one of the most comprehensive global databases of NNS (36,822 established species) to determine if NNS diversity is a representative proportional subset of global biodiversity. Results: Our study revealed that, while NNS diversity mirrors global biodiversity to a certain extent, due to significant deviance from the null model it is not always a representative proportional subset of global biodiversity. The strength of global biodiversity as a predictor depended on the taxonomic scale, with successive lower taxonomic levels less predictive than the one above it. Consequently, on average, 58%, 42% and 28% of variability in NNS numbers were explained by global biodiversity for phylum, class and family respectively. Moreover, global biodiversity was a similarly strong explanatory variable for NNS diversity among regions, but not habitats (i.e. terrestrial, freshwater and marine), where it better predicted NNS diversity for terrestrial than for freshwater and marine habitats. Freshwater and marine habitats were also greatly understudied relative to invasions in the terrestrial habitats. Over‐represented NNS relative to global biodiversity tended to be those intentionally introduced and/or 'hitchhikers' associated with deliberate introductions. Finally, randomness is likely an important factor in the establishment success of NNS. Main conclusions: Besides global biodiversity, other important explanatory variables for large‐scale patterns of NNS diversity likely include propagule and colonization pressures, environmental similarity between native and non‐native regions, biased selection of intentionally introduced species and disparate research efforts of habitats and taxa. [ABSTRACT FROM AUTHOR]

Ocean warming is impacting marine systems directly and indirectly via intensifying multiple stressors such as hypoxia, acidification and kelp forest collapse potentially exacerbating neoextinctions. Abalones are extremely vulnerable to both ocean warming and fishing stressors making them marine "canaries in the coal mine". The rare flat abalone, Haliotis walallensis, has been subject to a targeted commercial fishery and then exposed to an extreme marine heat wave. We examine the current status of flat abalone before and after a marine heat wave of 2014-2016 and the concomitant collapse of the bull kelp (Nereocystis leutkeana) forest in 2015. We find that flat abalone density (as assessed in surveys) and abundances (inside deployed "abalone modules") in the core of the range dropped to near zero after the marine heat wave and have not recovered. Further, we examine the status of flat abalone in southern Oregon after both overfishing and the kelp forest collapse and find dramatic declines, especially in former fishery hot spots. Our results show that flat abalone have experienced a major decline and may be an example of a neoextinction in the making. A standardized and well funded status review and proactive restoration plan, if not too late, are both critically needed for flat abalone throughout its range., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology.)