Abstract: Session D  2:45 pm (Back to Session D)
The San Antonio River Mission Reach Freshwater Mussel Survivability Study: A Case Study Using Freshwater Mussels to Assess Ecological Lift of the Upper San Antonio River Restoration

Chris Vaughn
San Antonio River Authority
San Antonio, TX

Freshwater mussels are an indicator organism that provide several important ecosystem services such as habitat availability, substrate stability, holistic nutrient availability and biofiltration. Unfortunately, freshwater mussels are one of the most rapidly declining groups of organisms in North America. Anthropogenic forces, most notably habitat degradation and the reduction of water quality and quantity, are among the leading drivers causing mussel imperilment. The Upper San Antonio River was likely once home to a large and diverse freshwater mussel population before early human inhabitation and subsequent mass urbanization caused a catastrophic shift in river conditions around the urban center. This stretch of river is now thought to have a limited population restricted to the remnant channels and Davis Lake. Conversely, the predominantly rural Lower San Antonio River has an extensive mussel population. The Mission Reach Restoration Project, completed in 2013, set out to restore the previously channelized eight mile stretch of The San Antonio River. This area has now been set up for higher resiliency against water quality and quantity issues, and as it matures and LID structures become more commonplace, conditions should improve. Multiple studies have been implemented since the restoration to highlight the ecological lift. One such study is the Mission Reach Freshwater Mussel Survivability Study. Freshwater mussels are being held across three sites in the Mission Reach and at a control site on the Lower San Antonio River to determine their fitness and growth in the restored area versus the “pristine” area. If it is determined that freshwater mussels can survive and thrive in the waters of the Upper San Antonio River then the reintroduction of these organisms could be possible in the future.