Effects of the invasive bivalve, Corbicula fluminea, on juvenile freshwater mussel survival and growth in laboratory experiments
摘要
Corbicula fluminea is a widespread aquatic invasive species that has major ecological effects. Corbicula is a proposed factor in global freshwater mussel declines, but its effects on mussels are poorly understood. We conducted five laboratory experiments to assess effects of Corbicula on juvenile mussel survival and growth and the modulating effects of food abundance, temperature, and the type of co-occurring bivalve. Corbicula had no effect on 60-day-old mussel survival. In two experiments, growth was higher in the presence of Corbicula; higher growth occurred only at low food in one experiment but not the other. Access to Corbicula pseudofeces did not produce higher growth, suggesting that mussels fed on suspended material. In another experiment, 60-day-old mussel growth was lower in the presence of Corbicula, but only at high food and warm temperature (29 °C). In contrast, 1-day-old juvenile survival was 50–70% lower in the presence of Corbicula, but neither food nor temperature modulated that effect. Growth was lower in the presence of Corbicula, but mainly at low food, suggesting food competition. In some cases, Corbicula had stronger effects than a similar biomass of adult native mussels, but in other cases their effects on juvenile mussels were similar. However, Corbicula removed most suspended food from experimental chambers 2–4h after feeding (at low and high food, respectively), but native bivalves removed substantial amounts of food only in the low food treatment. The strong negative effects of Corbicula on 1-day-old juveniles suggest that it may be an important factor in mussel declines.