Predicting the effects on endangered mussels from incremental decreases in minimum flows
Dates
Start Date
2009-10
End Date
2012-09
Citation
Moles, Kendall R. 2017. Lethal and sub-lethal physiological effects of behavioral responses of endangered freshwater mussels to reductions in streamflow. PhD. Dissertation. Tennessee Technological University, Cookeville, TN.
Summary
This SSP project resulted in a dissertation: Lethal and sub-lethal physiological effects of behavioral responses of endangered freshwater mussels to reductions in streamflow. Little is known about the behavioral responses and physiological effects of freshwater mussels to reductions in streamflow and their ecological significance, but movement behavior of animals is often an important adaptation for responding to changing environmental conditions. Mussels are primarily thought of as sessile organisms typically exhibiting little to no movement during their life span. To better understand this aspect of mussel ecology, flume, mesocosm, and in-situ field studies were conducted to determine behavioral responses to and the associated physiological [...]
Summary
This SSP project resulted in a dissertation: Lethal and sub-lethal physiological effects of behavioral responses of endangered freshwater mussels to reductions in streamflow.
Little is known about the behavioral responses and physiological effects of freshwater mussels to reductions in streamflow and their ecological significance, but movement behavior of animals is often an important adaptation for responding to changing environmental conditions. Mussels are primarily thought of as sessile organisms typically exhibiting little to no movement during their life span. To better understand this aspect of mussel ecology, flume, mesocosm, and in-situ field studies were conducted to determine behavioral responses to and the associated physiological effects of reductions in streamflow on freshwater mussels. A hydraulic flume was used to mimic decreasing streamflow conditions to identify the level of flow and determine the behavioral responses of 14 mussel species, including 11 federally-listed species. Mussels exhibited the greatest response when water levels were reduced to a depth of 5 cm and demonstrated one of two responses to deal with reductions in flow, by either burrowing into or moving laterally across the substrate. Although response type was consistent within species the magnitude of movement differed between genders, with males moving greater distances than females and non-brooding females moving farther than brooding females. In the mesocosm study, flow treatment and associated behavioral response type resulted in a reduction in growth, body condition, and reproductive potential. In the in-situ field study, behavioral responses to diminishing streamflow resulted in a reduction in growth, body condition, and survival. These behavioral responses represent two distinct strategies of mussels for responding to regular disturbances that occur as a result of changing flow conditions and water levels in their unstable lotic environment. This research has provided insight into the sub-lethal population level effects, both initial and delayed, of receding water levels on endangered freshwater mussels.
