Misleading estimates of economic impacts of biological invasions: Including the costs but not the benefits

Ecosystem services provided by the exotic bivalves Dreissena polymorpha, D. rostriformis bugensis, and Limnoperna fortunei

“…But when these species help to reverse other natural or human-induced undesirable effects (e.g., eutrophication vs. water clarification), or yield resources for exploitable or otherwise valued organisms (fishes, birds), our perception changes. We advocate for a broader and more holistic outlook of biological invasions in general, which should provide a more objective perspective of their impacts on the environment and on human well-being (Tassin & Kull, 2015 ; Boltovskoy et al, 2022 ). In this respect, novel ecosystems (Hobbs et al, 2013 ) deserve particular interest.…”

“…Damage estimates by invasive species attract more attention than their benefits (Jernelöv, 2017 ; Guerin et al, 2018 ), and assessments of damage only are dominant in the literature (Perrings et al, 2001 ; Pimentel, 2011 ; Diagne et al, 2021 ). However, as shown above, these invasive species do have sizable benefits, many of which involve major economic gains, but their ecosystemic and economic benefits are normally ignored, minimized, or deemed “non monetizable” (Boltovskoy et al, 2022 ). Given the widespread distribution of invasive mussels and the long-term focus of scientists and managers on the negative aspects of their dispersal, it is important to assess quantitatively their positive ecological effects and economic benefits.…”

“…In this context, many negative biological invasion-driven effects on the structure and functioning of ecosystems have been identified, but much less has been done evaluating and/or monetizing the ecosystem services provided by invasive species. The economic impacts of invasive species on these services are often neither quantified nor incorporated into economic impact assessments (e.g., Diagne et al, 2021 ), and many of their ecosystem services that are difficult to monetize are regularly ignored (Pejchar & Mooney, 2009 ; Thompson, 2014 ; Jernelöv, 2017 ; Boltovskoy et al, 2022 ). A vivid example are the three notable exotic ecosystem engineering bivalves, Dreissena polymorpha (Pallas, 1771) (the zebra mussel), D. rostriformis bugensis (Andrusov, 1897) (the quagga mussel), and Limnoperna fortunei (Dunker, 1857) (the golden mussel).…”

“…For example, water filtration by native mussels (Unionidae) can offset the negative impact of declines in water transparency, which is considered a service (Vaughn & Hoellein, 2018 ). However, because they commonly occur in higher densities, invasive mussels ( Dreissena spp., L. fortunei ) are much more efficient than native mussels in the clarification of water (Diggins, 2001 ; Leuven et al, 2014 ; Collas et al, 2020 ), but when only their negative impacts are considered (which, admittedly, are sizeable, especially for the industry; see “ Disservices, caveats, and unresolved issues ” section), they get no credit for these benefits (Boltovskoy et al, 2022 ).…”

Disentangling structural and functional responses of native versus alien communities by canonical ordination analyses and variation partitioning with multiple matrices

“…For instance, meta-analysis based on more than 200 publications aiming at characterizing relationships between native and alien species in all environments based on their traits and relationships to the environment revealed highly equivocal results regarding the actual impacts of invasive species 7 . Another review revealed that costs related to damage and economic losses are mostly miscalculated, while their benefits are usually neglected 8 .…”