This new role as Club Naturalist is kind of fun.† Itís already exposed me to a number of different issues.† For example, I was asked if I had any input as to the safe use of chlordane; an insecticide used for termite control, or in this case, for carpenter ant control in one of our cabins.† In as much as chlordane has been banned from commercial use in the US since 1988, I was glad to be able to point our Club in a more appropriate direction.
A more interesting situation arose when I was told a G1 species had been found just below our Vining properties.† A G1 species is one where only five populations or less are known to exist in the whole world! It turns out we are talking about a mussel, known as the James River spiny mussel.† So I spent two days in July wading through a stream with several US Fish and Wildlife biologists, members of the Nature Conservancy, and a few others, looking for this little creature.†† It actually was fun (except the part when I couldnít get my Toyota up the rain-soaked Virginia clay slope Ė but thatís another story, fortunately, with a happy ending).† Searching for the mussels was like an Easter egg hunt. These mussels are about two inches long, and generally look like clams (with notable exceptions, clams are marine and mussels are freshwater).† But they donít just lie on the sediment.† In fact, the shell is totally submerged in the substratum.† Only the two hose-like siphon tubes reach to the surface; one taking in water and suspended food sediments and the other expelling filtered water and waste products.† You have to look for a pair of dark spots less than a quarter inch apart on the creek bottom.† Over the two days, we found 223 notched rainbows, 22 Creeper or Squawfoot mussels, a number of an introduced species and, yes, 7 of our highly globally rare James River spiny mussel.† I was quite pleased with myself for finding 5 of the 7 spiny mussels!†
Armed with my newly gained experience (not to mention exuberance and self-confidence), a few weeks later, Jane Thompson, myself, and a new PATC herpetological friend, Will Brown, took to the waters of Swift Run and Madies Run that run through our Vining properties in search of this mussel.
It turns out that Virginia is a hot spot in the world for rare mussels.† The Clinch, Holston and Powell Rivers, located in southwestern Virginia, contain 31 federally listed Endangered and Threatened mussel species.† Not only that, this region also hosts a number of endangered fishes as well.† Some of these fishes are known as darters.† You remember the snail darter from the 70ís, donít you?†† In addition, a number of endangered bats and plants are also found here.
Why are so many endangered species located in this distant corner of Virginia?† It all has to do with the age of the community.† While the Alps, Rockies and Andes are about 60 million years old, our Appalachian Mountains are approximately 260 million years old.† This southern Appalachians habitat, free from glaciers and other dynamic ecological change, has enabled evolution to diversify into a myriad of forms and species.† In fact, the New River, contrary to itís name, is the second oldest river in the world, with only the Nile River being older.
Mussels have played a valuable role in the lives of east coast inhabitants, starting with the Native Americans, who used the mussel shells to make wampum, their form of money, or barter.† Our society made use of mussel shells to make buttons, until the advent of plastics in the 1930s.† Now, mussels are being collected and sold to Asian markets.† In the pearl farms of China, these shells are cut and shaped into round pearl replicas and placed into marine oysters.† The oysters proceed to coat the mussel shell with a thin layer of mother-of-pearl.† After two years, these are sold in the U.S. market as Ďcultured pearlsí.
Mussels are very sedentary.† These mussels, who can live to be 50 to 100 years of age, can spend years at a time in the same spot, content filtering food from the water with itís siphons.† Unlike migratory birds, ephemeral flowers and hibernating animals, mussels can be found any day of the year in the same place.† Mussels also have an interesting life cycle.† Females release newborn mussels, called glochidia, into the water where they must find their way to the gills of a fish, where they will live for about three weeks as a parasite before dropping off the fish to begin their life on the bottom.† Not just any fish will do, but these glochidia are limited to a very few acceptable fish species, and, in some mussel species, the glochidia can survive on only one species of fish.†
Alas, all is not bright for the mussel community.† In fact, through degradation of water quality, mussel populations have declined alarmingly in both abundance and diversity.† It has been said that mussels are far and away the most jeopardized faunal group in the country.† With 50 % of all U.S. species receiving protection under the Endangered Species list, some 70% of all mussel fauna are in peril.† However, the biggest threat has yet to arrive in our Virginian streams.† The zebra mussel, which has taken over much of the benthic community of Lake Erie, is rapidly approaching.† This introduced species, which, through itís filter feeding, has dramatically increased water clarity in the Great Lakes, has also removed the food from the waters that support the natural food chain, effectively removing many native mussels and game fish from hard hit areas.† Just this year, it has been identified in the upper reaches of the Susquehanna River in the Chesapeake Bay drainage basin.† Most biologists agree, itís just a matter of time before they infiltrate all of our eastern rivers, removing native species and clogging up water intake systems.†
So, what happened on our mussel search on the Vining properties?† It turns out that the sediment-rich depositions found downstream just donít exist in our upper reaches.† In the course of just a few miles, the character, and the benthic community, of the stream had changed from a sluggish meandering stream of deposition to one of high energy, steep gradient and erosion, with no mussels.† None-the-less, the James River spiny mussel has been a very satisfying experience, and one of many adventures I look forward to encountering as Club Naturalist.