Vleermuizen

A Catastrophe in the Making

A “biodiversity crisis”: that’s how some conservationists describe new numbers released this week by the federal Fish and Wildlife Service on so-called white-nose syndrome. According to the agency, 5.7 million to 6.7 million bats have died from the fungal ailment in eastern North America since an epidemic first broke out in upstate New York in 2006. The new numbers are striking, and far higher than the previous bat mortality estimate of one million released in 2009. What is known is that when the fungus gets into a cave or mine where bats are hibernating, 70 to 90 percent of the bats die. In some cases, the mortality rate is 100 percent.
Over the past three years, the disease has spread from 88 sites in nine states in 2009 to at least 200 sites in 16 states today. Jeremy Coleman, the lead white-nose syndrome coordinator for the Fish and Wildlife Service, said that officials can’t keep up with new site infections and are now working on the assumption that all caves and mines are infected in areas where the ailment has existed for several years.

Sommige experts vermoeden dat het immuunsysteem van vleermuizen - net als bij honingbijen - wordt verzwakt door neonicotinoide insecticiden

De vleermuizenpopulatie in de Verenigde Staten en Canada staat onder grote druk door een geheimzinnige schimmelziekte die intussen bekendstaat als het 'witteneuzensyndroom'. Wetenschappers hebben becijferd dat de aandoening in Noord-Amerika aan ten minste 5,7 miljoen vleermuizen het leven heeft gekost. De onderzoekers troffen vleermuizenkolonies aan waar 99 procent van de dieren door de schimmel bleek omgekomen. Sommige experts vermoeden dat het immuunsysteem wordt verzwakt door blootstelling aan subletale hoeveelheden van neonicotinoide insecticiden, waardoor vleermuizen - in analogie met honingbijen - zeer gevoelig worden voor pathogene organismen.

Fledermäuse als fleißige Gartenhelfer

In Wien leben 20 verschiedene Fledermausarten, österreichweit kommen 28 Arten dieser Insektenjäger vor. Fledermäuse arbeiten nächtens fleißig. Ihre Beutetiere sind häufig nachtaktive Insekten, darunter auch einige Schädlinge wie Apfel- und Pflaumenwickler, verschiedene Spanner, Mücken, Käfer und Fliegen. Fledermäuse sind stark bedroht: „Pestizide vergiften die Beutetiere der Fledermäuse und gefährden deren Bestand. Das Verzichten auf giftige Spritzmittel im Garten ist besonders wichtig für Fledermäuse und andere nützliche Tiere im Garten“, erklärt Mag.a Bernadette Pokorny, Gartenexpertin von "die umweltberatung".

Der Nahrungsmangel ist sicherlich eines der großen Probleme für unsere Fledermäuse

Wenn man bedenkt, dass etwa die Hälfte der mitteleuropäischen Insektenarten in der Roten Liste der vom Aussterben bedrohten Tierarten geführt wird, ist es unmittelbar nachvollziehbar, dass Tiere, die sich von Insekten ernähren, Schwierigkeiten haben, satt zu werden. Fledermäuse als einzige flugfähige Säugetiere stellen mit rund 1000 verschiedenen Arten weltweit die zweitgrößte Säugetierordnung. Nach einer überaus erfolgreichen Entwicklungsgeschichte über 60 Millionen Jahre hinweg kommt ein wenige Jahre währender dramatischer Rückgang. In Baden-Württemberg gelten 22 Arten als heimisch. In den letzten 30 Jahren brachen die Bestände um 80% ein, in Baden-Württemberg sind in dieser Zeit 4 Arten ausgestorben. Der Einsatz von Gift in Land- und Forstwirtschaft ist hier maßgeblich dran beteiligt. Zum einen werden die Insekten abgetötet und stehen den Fledermäusen nicht mehr zur Verfügung. Zum anderen werden Insekten durch Gift geschwächt und stellen dann eine besonders leichte Beute dar. Fledermäuse vergiften sich so selbst, sterben oder werden unfruchtbar oder bringen kranke oder tote Junge zur Welt. Das eigentlich hohe Lebensalter der Fledermäuse wird durch vergiftete Nahrung verkürzt, so dass eine ausreichende Reproduktion nicht möglich ist. Durch den Einsatz von Herbiziden auf den Äckern werden zahlreiche Wildkräuter verdrängt, die ebenfalls Nahrung für Insekten sind. Die Landschaft verarmt. Die Beseitigung von Hecken und Feldgehölzen, die Trockenlegung von Feuchtwiesen etc. beispielsweise im Rahmen von Flurbereinigungen zerstören ebenfalls Lebensräume für zahlreiche Insekten.

Bat populations are rapidly declining in North America

Bats are an amazingly diverse group of flying mammals that can be found in virtually every corner of the world. Most bats are harmless insect-eaters. Bat populations are declining worldwide, mostly because of habitat destruction and overuse of pesticides. One woman in the Washington area, who is working to improve public understanding of bats, is doing what she can to help them survive. As sunlight fades from the evening sky, Leslie Sturges checks on a colony of bats she has been monitoring. She's concerned that her count reveals only half the number of bats as last year. Sturges is director of a conservation group called Bat World NOVA. Sturges also teaches the importance of bats at nature centers and in schools. Her goal is to promote their protection and conservation by stressing the positive things bats contribute to the environment. “One of the things they contribute, well around here in North America, is pest control for plant-eating insects," said Sturges. "So anyone who grows anything is getting an assist from bats.”

With global value of $980 million in 2008, imidacloprid provides insect control for crops and noncrops

Imidacloprid, developed by Bayer CropScience in 1985, is an insecticide, a seed treatment insecticide and seed treatment insecticide/fungicide combination. Bayer still holds patents on the active for some formulations, specifically when combined with fertilizer. Its mode of action is nicotine acetylcholine receptor agonist/antagonist, and it is registered in more than 100 countries worldwide for use on more than 140 crops. It is used primarily on canola, cereals, corn, cotton, oil seed rape, pastures, potatoes, rice, sorghum, sugarbeet and sunflowers for approved control of aphids, fruit flies, leafhoppers, grubs, termites, thrips, white fly, wireworms, various beetles (including flea beetle and pygmy beetle), various weevils, nematodes and various fungal diseases. It also has widespread applications in noncrop, including nursery, landscape, forestry, pest control and veterinary applications. Bayer Animal Health has been using a 10% imidacloprid formulation for its popular Advantage/Advantix flea treatments for dogs and cats as early as 1986.

In Obstgärten finden unzählige Tiergruppen ihren Lebensraum

In Obstgärten finden unzählige Tiergruppen ihren Lebensraum: Vögel, Fledermäuse, Schläfer, Igel, Spinnen, Schmetterlinge, Schwebfliegen, Käfer und weitere Insektengruppen. Über 1000 Arten von Insekten, Spinnentieren und Tausendfüssler wurden in Obstgärten festgestellt. Besonders wichtig sind Obstgärten für Vögel: Rund 40 Brutvogelarten leben in der Schweiz im Lebensraum Obstgarten. Dies entspricht einem Fünftel der einheimischen Brutvögel.

Pipistrelles are thought to have undergone a significant decline in numbers in Britain

Bats are the world's only true flying mammals and one of the most diverse mammal groups on Earth. There are 16 recognised species of bats breeding in the UK. The Pipistrelles are Britain's smallest bats. Pipistrelles are the most common bats in towns and suburbs. Pipistrelles catch their food in flight and usually eat while on the wing. They mainly eat flies such as Midges and Caddis flies. They will also take Mosquitoes, Gnats, Mayflies, Lacewings and occasionally small Moths. Pipistrelles are thought to have undergone a significant decline in numbers. Estimates suggest a population decline of approximately 70% between 1978 and 1993. The increased use of insecticides has reduced the amount of insect prey available to Pipistrelles during their active season.

Our gardens become feeding stations for bees, butterflies, bats, hedgehogs, birds and other wildlife provided you don't use pesticides

We grow flowers in our gardens for our own enjoyment. But colour and perfume are really the plants’ way of advertising themselves to insects. Sweet nectar and protein-rich pollen are bait to encourage insects to visit. In return, pollen is carried from one flower to another on their bodies so the flowers are fertilised. Bees are among the most beneficial insects for a garden. The best way to attract them to your garden is to provide them with some of their favourite plants such as lavender, foxgloves, rosemary, sunflowers and bluebells. Flowers with long narrow petal tubes, such as evening primrose and honeysuckle, are visited by moths and butterflies. Only their long tongues can reach deep down to the hidden nectar. Short-tongued insects include many families of flies and some moths. They can only reach nectar in flowers with short florets. Hoverflies, wasps, ladybirds, lacewings, ground beetles and centipedes are the gardener’s friends and will help control garden pests such as aphids and caterpillars. Insects such as spiders, mites, millipedes, sow bugs, ants, springtails and beetles inhabit the soil food web in the uppermost 2 to 8 inches of soil. They participate in decomposing plant and animal residue, cycling nutrients, creating soil structure and controlling the populations of other soil organisms, including harmful crop pests. Decaying organic matter in soil is the source of energy and nutrients for garden vegetables and ornamental plants. By growing flowers attractive to a range of insects, our gardens can also become important feeding stations for bats, hedgehogs, birds and other wildlife. The most important factor when encouraging wildlife into your garden is not to use insecticides.

U.S. bat populations have been declining at an alarming rate since 2006

The appropriately named fungus Geomyces destructans is the cause of deadly white-nose syndrome (WNS) in bats, according to research published in the journal Nature. The study by U.S. Geological Survey scientists and partners, conducted at the USGS National Wildlife Health Center in Madison, Wisc., provides the first direct evidence that the fungus G. destructans causes WNS, a rapidly spreading disease in North American bats. U.S. bat populations have been declining at an alarming rate since 2006, when white-nose syndrome first appeared in New York State. Since then, the fungus G. destructans has spread southward and westward and has now been found in 16 states and 4 Canadian provinces. Bat declines in the Northeast, the most severely affected region in the U.S., thus far have exceeded 80 percent.