Two centuries of spatial and temporal dynamics of freshwater fish introductions

Abstract

AimInvestigating major freshwater fish flows (translocations) between biogeographic regions and their temporal dynamics and also quantifying spatial patterns and temporal changes in the array of introduced species, and the emergence and distance between major donor and recipient regions.LocationGlobal.Time Period1800–2020.Major Taxa StudiedFreshwater fishes.MethodsWe analysed a global dataset on freshwater fish introductions (4241 events of 688 species). Freshwater fish flows were investigated with flow diagrams and χ2 tests, while PERMANOVA (permutational multivariate analysis of variance) was used to test the association between species and regions and temporal shifts. Cluster analysis revealed major recipient areas and composition of the introduced species. Finally, changes in distances between donor and recipient sites were tested with PERMANOVA.ResultsThe number of introductions between biogeographic regions mirrored the European and North American dominance before World War II (WWII) and the trends in recreational fishing, biocontrol programmes and food production, especially in the Sino‐Oriental region, which has a long tradition of aquaculture and fishkeeping. Over the years, the origins and composition of introduced species changed uniquely in each biogeographic region, although the most introduced species are common to every region. Salmonids and other cold‐water species were frequently introduced before the 1950s, whereas tropical ornamental and aquaculture species currently prevail. Distances between donor and recipient sites did not vary over the time. After WWII, the Sino‐Oriental region consolidated its dominance and the Ethiopian and Neotropical regions emerged as new global donor and recipient regions.Main ConclusionsGlobal policy should focus on tropical ornamental and aquaculture species, which could benefit from global warming, especially in the Sino‐Oriental region, because it currently dominates freshwater fish species flows, and the Ethiopian and Neotropical regions, because they recently emerged as important global donor and recipient regions of freshwater fish introductions.

Major shifts in biogeographic regions of freshwater fishes as evidence of the Anthropocene epoch

“…Our Anthropocene results represent the present-day status of freshwater fish biogeographic regions, and these changes occurred rapidly, as evidenced by the temporal trends in introductions ( 54 ). Although the onset of global introductions started in the 19th century, the number of introductions and diversity of introduced species remained low until the mid-20th century ( 54 ). An abrupt change was identified in 1947, with a marked acceleration in introductions worldwide, and a globalization of the origins and destinations of introduced species ( 54 ).…”

“…Although the onset of global introductions started in the 19th century, the number of introductions and diversity of introduced species remained low until the mid-20th century ( 54 ). An abrupt change was identified in 1947, with a marked acceleration in introductions worldwide, and a globalization of the origins and destinations of introduced species ( 54 ). This mid-20th century abrupt change in patterns of introductions likely marks the cut-off date for the alterations of natural biogeographical regions we described here.…”

Analysing spatio‐temporal patterns of non‐native fish in a biodiversity hotspot across decades

“…A comprehensive understanding of the spatio-temporal patterns and dynamics of non-native species empowers us to formulate effective strategies for prevention and management (Azzurro et al, 2022;Muñoz-Mas et al, 2023). Our findings undoubtedly offer important insights for preventing and managing non-native species, both in biodiversity hotspots such as Yunnan and elsewhere around the globe.…”

“…Consequently, most countries and regions worldwide have enacted relevant laws and regulations, as well as developed evidence-based prevention and management measures to mitigate the ecological and economic impacts of biological invasions (Turbelin et al, 2017). Nevertheless, the effectiveness of implementing these management measures critically depends on a clear understanding of the spatio-temporal patterns and dynamics of non-native species (Azzurro et al, 2022;Daga et al, 2015;Muñoz-Mas et al, 2023;Vitule et al, 2012). This is because, based on this foundation, researchers can predict the spreading trend of non-native species and forecast changes in invasion situations for specific regions (Liu et al, 2019), while managers and policymakers can timely identify key non-native species and delineate priority areas for designing effective prevention and management strategies (Magalhães et al, 2020;Pyšek et al, 2020).…”

“…Freshwater ecosystems are particularly vulnerable to invasion by non-native animals and plants (Bando et al, 2023;Moorhouse & Macdonald, 2015). Because of economic and recreational purposes, fish species, in particular, are frequently introduced into freshwater ecosystems globally, resulting in their widespread establishments and often leading to freshwater biodiversity declines and, in the worst case, ecosystem collapses (Cucherousset & Olden, 2011;Muñoz-Mas et al, 2023;Su et al, 2021). To effectively conserve freshwater biodiversity and ecosystem functions, as well as inform management strategies, it is essential to unravel the mechanisms behind successful invasions through analysing the spatio-temporal patterns and understanding the dynamics of non-native fishes (Azzurro et al, 2022).…”