engleski

Invasive vs. native bivalves - differences in tolerance to anthropogenic stress

Tolerance towards environmental stress has been frequently considered as one of the key determinants of invasion success. However, empirical evidence supporting the assumption that invasive species endure unfavourable conditions better compared to native species is limited and has even yielded opposing results. We examined tolerance to thermal stress and heavy metal zinc pollution (ZnCl2) in two phylogenetically related and functionally similar freshwater bivalve species ; the native Anodonta anatina and the invasive Sinanodonta woodiana. We assessed their response to stress using several cellular response assays: metabolic rates (ETS - electron transport system), efficiency of the multixenobiotic resistance (MXR) mechanism activity, and enzymatic biomarkers (ChE - cholinesterase, GST - glutathione-S-transferase and CAT - catalase). Overall, S. woodiana coped with unfavourable conditions much better. This was evident from (i) a significantly more pronounced MXR mechanism activity ; (ii) significantly higher ETS activity, and (iii) lower response of stress-related enzymes (ChE, GST and CAT) under thermal stress and ZnCl2 pollution. The overall better tolerance to thermal extremes is an especially important physiological advantage for the future of invasion success of S. woodiana in European freshwaters, especially in the context of climate change.

freshwater mussels; heavy metal zinc pollution; invasion success; metabolic rate; MXR mechanism activity; thermal stress

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