Thursday, May 26, 2011

America's Bats are Dying

Update: US Fish & Wildlife has come up with a national plan to combat the deadly fungus Geomyces destructans that has killed over a million North American bats since 2006. The fungus was described in 2008 by Blehart et al and identified as a unique species in 2009 by Gargas et al. The Service says the plan provides a coordinated response for investigating the syndrome and finding a means to prevent spread of the disease. Until an exact disease mechanism is understood by science, quarantine of infected colonies, and restrictions on human disturbance of at risk hibernaria seems warranted. Over $10.8 million has been invested by the Department of Interior to find ways to control or cure the disease.

More: {27/4/11} Kentucky is the 16th state to report the presence of the killer fungus decease infecting America's bats. A little brown bat from a Trigg County cave tested positive for the "white nose syndrome". The privately owned cave is a hibernaculum for six species, including the endangered Indiana bat, numbering about 2,000. Sixty very sick bats not expected to survive were removed from the cave and euthanized by wildlife authorities. Mortality rates are approaching 100% in caves that have multi-year infections. The Kentucky Department of Fish & Wildlife has promised to protect bats in the vicinity from infection. No other nearby caves were found to be infected, so far. Bats are a tremendously beneficial species to man, acting as both insectivores and pollinators.

{7.4.11}This tragic story has not received the attention it deserves because bats are up there with bees when their contribution to human agriculture is considered. Bats in the US are dying in the millions from a mysterious fungal disease named "white nose syndrome". More study of the disease is justified solely from an economic standpoint. Bats eat tons of harmful insects every year that would otherwise damage human crops. A paper in the peer journal, Science, estimates the value of their services to agriculture may be around $22.9 billion a year. The disease has spread across the northeast and into Canada, wiping out entire colonies. The little brown myotis bat (Myotis lucifugus) is threatened with regional extinction by the pathogen. The Center for Biological Diversity has warned that unless action is taken now, the disease will spread across the country. Cave and abandoned mine closures are called for to prevent the human transmission of the fungus to healthy colonies of bats. Research has shown that the fungus lives in subterranean soils and can be transmitted on clothing and gear to new sites. Evidence points to a European source of the disease where the fungus has been identified but does not affect bats. The US Fish & Wildlife Service said the white nose epidemic is the worst wildlife health crisis in memory, and the agency is not prone to hyperbole. In December 2009 the agency completed a report recommending closures of caves and mines where infected bats are hibernating. In some hibernacula 90-100% of the bats are dying.

The disease was first noticed in 2006 in nesting caves near Albany, New York. Two years ago the disease was estimated to have killed more than a million bats. Now, it has spread to six different species and last spring the fungus was detected on a bat found in western Oklahoma. Public lands with subterranean sites are largely open to unrestricted entry in the American west. The Bureau of Land Management has no current plans to restrict cave access, but the passive wait and see approach is clearly inadequate if America's beneficial bats are not to go the way of the Tasmanian Devil.