Table 1 Descriptions of the type, the modalities and the hypothesis and justifications of all the variables used
Variable type | Variable | Variable modalities | Hypothesis/justification |
|---|---|---|---|
Response variable | Number of countries, where the species: (i) is introduced (ii) is established (iii) has ecological impacts (for all species and the ornamental fish trade and aquaculture pathways) | Quantitative variables | – |
Species characteristics | Main diet | • Detritus • Nekton • Plants • Zoobenthos • Zooplankton | Broad food spectrum, piscivorous diet, as well as some specialized diets facilitate establishment (Ruesink 2005; Tonella et al. 2018). A nekton diet can be associated with species having an impact (Moyle and Light 1996; Howeth et al. 2016) |
Number of diet categories | Quantitative variable | ||
Hydrodynamics | Quantitative variable | Good swimming ability enables fish to colonize new regions, spread, establish, and have wide impacts (Carvajal-Quintero et al. 2019) | |
Pectoral fin vertical position | Quantitative variable | ||
Parental care | Ordered categorical variable • Non-guarder • Guarder • Bearer | A high level of parental care facilitates establishment (Marchetti et al. 2004b; Lawson and Hill 2022) | |
Total length (TL) | Quantitative variable | At the introduction step, the body length of successful species is linked to the introduction pathway (Wonham et al. 2000; Su et al. 2020). At the establishment step, body length depends on the environmental conditions (Vila-Gispert et al. 2005). At the impact step, small species can have greater impacts (Marchetti et al. 2004a, b) | |
Taxonomy | • Cypriniformes • Cyprinodontiformes • Siluriformes • Perciformes • Characiformes • Other | Taxonomic order is a surrogate for missing characteristics that could influence species success at different stages of the invasion | |
Ecological characteristics | Temperature range in the native basins | Quantitative variable | Temperature range in native basins can be a proxy of temperature tolerance. Temperature tolerance influences the establishment and spread of invasive species (Kolar and Lodge 2002; Marchetti et al. 2004b; Snyder et al. 2014) |
Maximum temperature in the native basins | Quantitative variable | ||
Main native bioregion | • Nearctic • Palearctic • Sino-Oriental • Neotropical • Ethiopian • Madagascan | Native bioregions roughly reflect environmental conditions | |
Socioeconomic characteristics | Use by humans | Yes/no | Species used by humans have greater chances of being introduced than those not used by humans |
Aquaculture | 1/0 Quantitative variable | Introduction pathways constrain the characteristics of introduced species (Wonham et al. 2000; Su et al. 2020) The number of introduction pathways is linked to high propagule pressure | |
Sport/Angling | |||
Accidental | |||
Ornamental | |||
Fisheries | |||
Diffusion | |||
Species control | |||
Number of introduction pathways |