STATUS OF THE FEDERALLY THREATENED ROUND HICKORYNUT (OBOVARIA SUBROTUNDA) IN ALUM CREEK, DELAWARE COUNTY

Abstract

The Round Hickorynut, or Obovaria subrotunda, was recently listed as a federally threatened species by the United States Fish and Wildlife Service (USFWS). This freshwater mussel is one of the many species in North America that are in peril. Freshwater mussels are crucial to ecosystems they reside in, providing valuable services to humans, like water filtration, and other organisms, like food and habitat. Native mollusks get put into peril by human intervention through activities like pollution, the introduction of nonnative organisms, and hydromodification of streams. Alum Creek, in Delaware County, Ohio, has been known to house O. subrotunda historically. To have accurate information for future conservation efforts regarding this species, a section of this stream was surveyed. This section is between Alum Creek Dam upstream to the Water Treatment Plant impoundment Westerville, Ohio. The presence of recently living Round Hickorynut were found, but no live individuals were recorded. This study resulted in the discovery of an extant population of this mussel in this reach of Alum Creek. The population was most abundant at River Mile 24.9 with no specimens found immediately downstream of the Alum Creek Dam (RM 25.9-26.2) and within the impoundment of the Westerville Water Treatment Plant (RM 21.5-21.9). Hydromodification (Alum Creek Dam and Westerville Water Plant impoundment) and competition with the Asiatic Clam (Corbicula Fluminea) are the two major factors affecting O. subrotunda in this reach of Alum Creek. Future status survey work should concentrate on RM 24.4-25.1 where mussel density and number of O. subrotunda were greatest. The most abundant number of mussels was at river mile RM 24.9. The site with the greatest species richness and species diversity was at RM 25.1