| Abstrakt: |
Suspended solids are one of the most widespread pollutants in streams, but little is known about their effects on freshwater mussels. In a previous study, we showed that increasing concentrations of total suspended solids ( TSS) resulted in a decreased proportion of gravid female mussels; however, the generality of this effect and the specific stage at which reproduction was inhibited remain unknown., In this study, we examined stage-specific disruption of reproduction in a short-term brooding mussel species ( Reginaia ebenus) and a long-term brooding species ( Ligumia subrostrata)., High TSS concentrations disrupted reproduction in both the short- and long-term brooding species, but the mechanism appeared to differ between species. A high proportion of female Reginaia ebenus (range = 0.33-0.93) were fertilised across the entire TSS gradient (11-92 mg L−1), but few glochidia developed at TSS >20 mg L−1. In contrast, only a low proportion (0-0.28) of female Ligumia subrostrata were fertilised at high TSS concentrations, but all gravid females eventually produced fully developed glochidia., Excessive inputs of sediments and/or nutrients probably disrupt early reproductive stages of freshwater mussels via elevation of inorganic or organic TSS concentrations and may be important drivers of freshwater mussel declines. [ABSTRACT FROM AUTHOR] |
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