Ohio River Navigational Pools
To gain an understanding of the natural resources of a large river with many human influences, WPC set out to survey the Ohio River’s freshwater mussels.
The upper river drains a 23,500 square-mile watershed in Pennsylvania, New York and West Virginia. Its basin encompasses diverse urban, agricultural and natural landscapes. Once a river of flowing riffle and runs dotted with islands, the Ohio River was converted to slow, deep pools when the navigational pools
were created in the late 19th century. Since the industrial revolution, the river has received pollution from resource extraction (e.g., coal mining and timber), manufacturing (e.g., steel, glass and other materials) and storm water. Additionally, the river is also a route for the transport of goods. Barges buzz through the locks and dams, moving coal and other materials every day of the year.
Despite past and ongoing threats, the river has experienced improvements in water quality since the peak of industrial pollution. While many assume that there is little life in the deep, silty waters of the river, recent studies of fish indicate that the river is recovering.
Because mussel communities in the Ohio River are still under-surveyed, divers from the Pennsylvania Natural Heritage Program don SCUBA gear and descend to transect lines on the river bottom. Feeling for shells in the top layer of sediments and looking for the telltale shape of mussel siphons, divers pull up freshwater mussels from the sandy river bottom.
Mussel diversity, habitat preferences of species encountered and evidence of population recruitment are useful for managing the river’s resources. Information from surveys and distribution modeling about the freshwater mussel communities, particularly any discoveries of species not seen in the river in recent decades or those that prefer high-quality habitat, are also beneficial to the management of the river.
A survey of Pennsylvania’s portion of the Ohio River produced data that informed local management as well as an Ohio River basin mussel species distribution model. The model analyzed the relationships between the landscape and watershed features with the occurrence of freshwater mussels. The results of species distribution modeling can be used to inform future targeted surveys and provide landscape-level insight into the factors that are related to and influence mussel habitat.
Brook Floater and Eastern Lampmussel Distribution
Updated species distribution data for two imperiled species, brook floater (Alasmidonta varicosa) and eastern lampmussel (Lampsilis radiata), was identified as a critical conservation need necessary to inform management of these mussels. PNHP biologists conducted extensive surveys, analyzed distribution data, and completed assessments of the species conservation status. The significant range decline and decrease in population sizes of the brook floater and eastern lampmussel suggest that these species are reaching a critical threshold for conservation.
In previous studies, PNHP biologists have failed to find brook floater and eastern lampmussel at many sites where they historically occurred. Rangewide, both species have documented habitat along the Atlantic Coast of the eastern United States but more information must be gathered to fully understand the extent of remaining habitats and threats to these mussels.
Project staff revisited historic locations and sites that had not been surveyed in years to search for brook floater and eastern lampmussel and determine where habitat remains for both species. We estimated population density and collected water quality and habitat information at survey locations. Distribution models for both species were developed to better understand the relationship between landscape characteristics and each species’ habitat. Information gathered from this project was applied to conservation status assessments.
