Calcium concentrations in the lower Columbia River, USA, are generally sufficient to support invasive bivalve spread

Abstract

Dissolved calcium concentration [Ca 2+ ] is thought to be a major factor limiting the establishment and thus the spread of invasive bivalves such as zebra (Dreissena polymorpha) and quagga (Dreissena bugensis) mussels. We measured [Ca 2+ ] in 168 water samples collected along $100 river-km of the lower Columbia River, USA, between June 2018 and March 2020. We found [Ca 2+ ] to range from 13 to 18 mg L À1 during summer/fall and 5 to 22 mg L À1 during the winter/spring. Previous research indicates that [Ca 2+ ] < 12 mg L À1 are likely to limit the establishment and spread of invasive bivalves. Thus, our results indicate that there is sufficient Ca 2+ in most locations in the lower Columbia River to support the establishment of invasive dreissenid mussels, which could join the already widespread and abundant Asian clam (Corbicula fluminea) as the newest invader to an already heavily invaded Columbia River ecosystem. These new data provide important measurements from a heretofore undersampled region of the Columbia River and have important implications for the spread of invasive bivalves and, by extension, the conservation and management of native species and ecosystems.

Broadscale distribution, abundance, and habitat associations of the invasive Asian clam (Corbicula fluminea) in the lower Columbia River, USA

“…Other environmental variables, not measured by us in this study, are also likely to be important in regulating the abundance of C. fluminea , in particular calcium (and potentially other ions) and predation. For example, Bollens et al (2021) found that calcium concentrations necessary for supporting invasive bivalves like C. fluminea and Dreissena spp. are sufficient throughout the lower CR; however, the influence of organic or other inorganic nutrients have yet to be assessed in the CR.…”

“…C. fluminea has since become well established in the CR (Henricksen & Bollens, 2022), reaching population densities of up to 722 individuals m −2 (McCabe et al, 1997). Despite these 80+ years of occurrence in the CR, as well as its known harmful effects in other invaded ecosystems, only a very limited body of scientific literature exists on the ecology of pelagic juveniles (Dexter et al, 2015;Dexter, Katz, Bollens, et al, 2020;Hassett et al, 2017) and benthic adult C. fluminea in the CR (Bollens et al, 2021;Henricksen & Bollens, 2022;McCabe et al, 1997;Rollwagen-Bollens et al, 2021), particularly regarding this species' habitat associations. variables, in its invaded range of North America, South America, and Europe, as well as its native range in Asia, Africa, and Australia, and to compare these findings to our results from the lower CR.…”

“…Thus, the abundance of chl-a, as was used in our current study and many previous studies by others (Table2), has only limited utility in assessing the role of food availability in regulating C. fluminea abundance, and thus future studies could consider more taxonspecificity in their assessment of food quantity and quality.Other environmental variables, not measured by us in this study, are also likely to be important in regulating the abundance of C. fluminea, in particular calcium (and potentially other ions) and predation. For example,Bollens et al (2021) found that calcium concentrations necessary for supporting invasive bivalves like C. fluminea and Dreissena spp. are sufficient throughout the lower CR; however, the influence of organic or other inorganic nutrients have yet to be assessed in the CR Sousa et al (2008b).…”