The Ozark Hellbender: Out from Under a Rock
(The following is an excerpt from an article in the Enangered Species Bulletin by Jill Utrup and Kim Mitchell)
What lurks below the clear waters of Ozark streams? Well, it's not pretty, but it is pretty cool. The Ozark hellbender, which can reach a length of about 2 feet, is one of the largest salamanders in the world.
These strictly aquatic salamanders are found only in Ozark streams of southern Missouri and northern Arkansas. Most of their life is spent beneath rocks in fast-flowing streams. They come out from under their rocks at night to eat crayfish and in the fall to mate. It takes them five to eight years to reach sexual maturity, and they live 25 to 30 years in the wild (55 years in captivity). Males and females may prey upon their own and others' eggs.
With numerous threats to these amphibians and their habitat, Ozark hellbenders are declining in numbers throughout their range. Because of the hellbender's long lifespan, it took some time before researchers recognized the rapidity of the decline. Even in areas that until recently were thought to have healthy, stable populations, numbers have plummeted. Particularly disconcerting is the fact that most populations have only older individuals. The lack of juveniles indicates that there has been little to no reproduction for several years.
What happened? The Ozark area is famous for its beauty and fast, clear rivers, which are fun to canoe, kayak, and fish. But that clear water and pretty scenery can be deceiving. The story of the Ozark hellbender's decline is an all too familiar one - increased siltation, water quality degradation, and increased impoundments.
To add insult to injury, the highly infectious chytrid fungus is proving fatal to an ever-increasing number of amphibians throughout the world. Over 75 percent of hellbender deaths that occurred in the St. Louis Zoo's captive population from March 2006 through April 2007 were due to this disease. This prompted the testing of Missouri's wild Ozark hellbenders. The results showed that the chytrid fungus was present in all remaining populations of the Ozark hellbender in Missouri.
Researchers view chytrid as one of the most, if not the most, challenging threat to the survival of this subspecies, whose population size is estimated at no more than 590 individuals. Additionally, abnormalities in Ozark hellbenders are becoming increasingly more severe. Although these abnormalities have not been linked conclusively with the presence of chytrid, considering that the types of abnormalities documented (e.g., lesions, digit and appendage loss, epidermal sloughing) are similar to the symptoms of the chytrid fungus, it is possible that there is a connection.
The recovery of aquatic species is particularly challenging because the threats are usually difficult to identify and address. The Ozark hellbender's situation is also a sign of the times in endangered species conservation, as global threats such as climate change add to local environmental problems. Conservationists are rising to these challenges by looking beyond agency and geographical boundaries to collaborate and share resources, make the most of limited dollars, and persevere.
On September 8, 2010, the Service proposed to extend Endangered Species Act protection to the Ozark hellbender. A final decision is expected in September 2011.
The complete article and other information on Ozark hellbender can be found at http://www.fws.gov/midwest/Endangered/amphibians/ozhe/index.html