Vleermuizen

Im Anflug gleitet die Fledermaus beinah lautlos durch die Luft. Das Säugetier orientiert sich per Echolot und Ultraschall und ernährt sich von Insekten. Sie fressen Insekten, die sie im Flug erbeuten, indem sie ihren »Mantel« als Kescher einsetzen. Von den weltweit rund 750 Fledermausarten leben 22 in Deutschland. Alle sind bedroht und stehen auf der Roten Liste der gefährdeten Säugetiere. Viele verunglücken schlicht im Straßenverkehr. Mit jedem Totholz- Baum, der aus dem Wald verschwindet, vergrößert sich ihre Wohnungsnot. Durch den Einsatz von Insektiziden wird das Nahrungsangebot der Insektenfresser vergiftet. Und ohne Nahrung und Herberge können Fledermäuse nicht überleben.

Weltweit sind rund 850 Fledermausarten bekannt. 25 der 28 Fledermausarten der Schweiz sind heute bedroht und alle Arten geschützt. Drei Fledermausarten haben so kleine Bestände, dass sie vom Aussterben bedroht sind. Die Verarmung der Landschaft und der massive Rückgang der Insektenvielfalt sind Hauptgründe für den starken Rückgang. Einheimische Fledermäuse ernähren sich ausschliesslich von Insekten. Der Rückgang der Insektenvorkommen ist eine Folge der Intensivierung der Landwirtschaft (durch Insektizide, Kunstdünger, Monokulturen). Zudem wirkten sich Bodenverbesserungen(Meliorationen) und Strukturausräumungen in der Landschaft negativ aus.

“White-nose syndrome is causing such catastrophic mortality that it may be the worst wildlife catastrophe in the last hundred years,” said Rob Mies, who is director of the Organization for Bat Conservation. A deadly fungus that has been in the United States for only five years, white-nose syndrome has already killed more than a million bats. One of the most affected species is the little brown bat, a mouse-sized bat that often roosts in suburban attics. Because of white-nose syndrome, Mies said, the “little brown bat could go from one of the most common mammalian species in North America, to one of the least common, if not extinct.”

A disease spreading rapidly through the state’s bat population has led to a 70 percent decline in the number of bats hibernating in mines and other sites surveyed by state researchers over the past two years, wildlife officials said.

A fungus known as White Nose Syndrome is killing off many species of bats in New Hampshire and across the Northeast after it first appeared in the state a few years ago. “A 70 percent decline in our small sample of hibernation sites is dramatic,” said John Kanter, a wildlife biologist with state Fish and Game who runs the state’s non-game and endangered species wildlife program. The state monitors the bat population by regularly surveying eight mine sites around the state where bats are known to hibernate.

In Jefferson County, the bat population has declined more than 50 percent during the past couple of years. White-nose syndrome, a white fungus that collects on the noses and wings of hibernating bats, has killed more than 1 million cave-hibernating bats in the state since it was first discovered near Albany in 2006. Since then, the fungal disease has spread to other states and several provinces in Canada.

We have been pondering on the significance of the laboratory evidence from Bee Researchers in France and the US that the administration of tiny amounts of a systemic neonicotinoid, imidacloprid, to bees was associated with a weakening of bee immunity, such that they became more susceptible to bee diseases. and decided to look more closely at the patterns of recent deaths/epidemics in the UK, Europe and the US, involving a variety of other wildlife. In March 2009 (published Feb 2010), Puechmaille et al. found the White-nose Syndrome Fungus (Geomyces destructans) on a single bat in a cave in France, but without other evidence of disease [1]. They raised the possibility that the fungus was not the primary cause of death “but acts as an opportunistic pathogen in bats already immune-compromised by other pathogens such as viruses or bacteria”.

We have been pondering on the significance of the laboratory evidence from Bee Researchers in France and the US that the administration of tiny amounts of a systemic neonicotinoid, imidacloprid, to bees was associated with a weakening of bee immunity, such that they became more susceptible to bee diseases. and decided to look more closely at the patterns of recent deaths/epidemics in the UK, Europe and the US, involving a variety of other wildlife. It was 2006 when White Nose Syndrome (WNS), a virulent and fatal fungus disease of hibernating bats, came to the attention of ecologists [1]. It was first found in a cave in New York State in the 2005/6 winter and rapidly spread through the north-eastern states. A powdery white nose tip was pathognomonic of the disease and when the powder was cultured a fungus, Geomyces destructans was grown. This infected the skin and wing membranes of bats and was associated with unprecedented numbers of deaths. It affected six different species of bat.