Invasive alien species are a major driver of global change, impacting biodiversity, ecosystem services, and human livelihoods. To document these impacts, we present the Global Impacts Dataset of Invasive Alien Species (GIDIAS), a dataset on the positive, negative and neutral impacts of invasive alien species on nature, nature’s contributions to people, and good quality of life. This dataset arises from the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services’ (IPBES) thematic assessment report of this topic. Data were compiled from published sources, including grey literature, reporting a direct observation of an invasive alien species’ impact. All impact records contain up to 52 fields of contextual information and attempt to link impacts to the global standard “environmental impact classification for alien taxa” (EICAT) and “socio-economic impact classification for alien taxa” (SEICAT). GIDIAS includes more than 22000 records of impacts caused by 3353 invasive alien species (plants, vertebrates, invertebrates, microorganisms) from all continents and realms (terrestrial, freshwater, marine), extracted from over 6700 sources. We intend GIDIAS to be a global resource for investigating and managing the variety of impacts of invasive alien species across taxa and regions.

Many alien species have been introduced around the world as part of the pet trade, and some have escaped captivity and become invasive. In South Africa, many species of tarantula (Theraphosidae) are kept as pets. It is not known which species are traded, which are most popular, and whether their names are correctly applied. Online traders and physical pet stores were investigated between 2015 and 2016 to determine the extent or size of trade, species composition, most popular species, and their invasion history elsewhere. In total, 36 specimens, three individuals from 12 putative species, were also purchased for DNA barcoding targeting the COI gene region to quantify the accuracy of tarantula identification by traders. In total, 195 tarantula species were advertised for sale, and the most popular species were Brachypelma albopilosum Valerio, 1980 (n = 199), B. vagans Ausserer, 1875 (n = 132), and Grammostola rosea Walckenaer, 1837 (n = 120). The composition of shared species differed between the sources and most of the species were advertised online. Only one of the popular species, B. vagans, has been recorded as being invasive elsewhere. Only 36% of the barcoded specimens matched existing barcodes in online repositories that had the same species name. The three individuals from 12 putative species were not in the same terminal clade as those of conspecifics in the Barcode of Life Data System (BOLD) and the NCBI GenBank reference sequences. A large proportion of the known tarantula species are traded in South Africa and must be included in management and risk assessments to avoid potential invasions.

The pet trade is one of the most important pathways by which small mammals are introduced to non-native areas. To prevent the introduction and invasion of non-native pets, an impact assessment protocol is useful in understanding which pets might have potential negative impacts should they escape or be released from captivity. In this study, we used the Generic Impact Scoring System (GISS) to assess the potential effects associated with 24 non-native small mammal species sold in the South African pet trade. European rabbits Oryctolagus cuniculus, house mice Mus musculus, Norwegian rats Rattus norvegicus and eastern grey squirrels Sciurus carolinensis had the highest potential impacts for both socio-economic and environmental categories. We found no statistically significant difference between the overall environmental and socio-economic impact scores. Impacts on agricultural and animal production (livestock) were the main mechanisms in the socio-economic category, while the impacts on animals (predation), competition and hybridisation prevailed for environmental impacts. The non-native mammal pet species with high impacts should be strictly regulated to prevent the potential impacts and establishment of feral populations in South Africa.