Algemeen

Rund 600.000 Einzeldatensätze für 33 heimische sowie 14 eingeschleppte Amphibien- und Reptilienarten, die einen bundesweiten Überblick über deren Verbreitung vermitteln. Das ist das Ergebnis eines Projektes, das die Deutsche Gesellschaft für Herpetologie und Terrarienkunde (DGHT) im Auftrag des Bundesamtes für Naturschutz durchgeführt hat. Daraus entstanden ist der erste Online-Atlas der Amphibien und Reptilien für Deutschland, der ab sofort auf der Website www.feldherpetologie.de/atlas abrufbar ist. Der Online-Atlas liefert nun – 18 Jahre nach dem Standardwerk der Amphibien und Reptilien Deutschlands von Rainer Günther – einen umfassenden Datenfundus für eine zukünftige Revision der Roten Listen der Amphibien und Reptilien Deutschlands und zeigt, welche Arten am häufigsten und welche besonders selten sind. Zu den sehr häufigen Arten zählen bei den Amphibien die Erdkröte und der Grasfrosch, bei den Reptilien Blindschleiche, Waldeidechse und Zauneidechse. Sehr selten ist bei den Amphibien der Alpensalamander, der seinem Namen entsprechend tatsächlich nur im Alpengebiet vorkommt. Bei den Reptilien sind fast die Hälfte der 13 Arten extrem selten, beispielsweise die Europäische Sumpfschildkröte, die Würfelnatter und die Aspisviper.

A new federal study documents for the first time that a specific fungus is the cause of a disease that is killing an unusually high number of snakes in the Eastern and Midwestern U.S. The findings announced Tuesday by the U.S. Geological Survey determined that a fungus known as Ophidiomyces ophiodiicola is the cause behind the skin infections known as snake-fungal disease. Outbreaks of the sometimes fatal disease have been confirmed over the past decade in nine states: Illinois, Florida, Massachusetts, Minnesota, New Jersey, New York, Ohio, Tennessee and Wisconsin. By pinpointing the cause of the disease, scientists can better help conserve snake populations threatened by the disease that play an important role in the environment, said Jeffrey Lorch, a USGS National Wildlife Health Center scientist and lead author of the study published in the online journal mBio. Among other benefits, snakes help keep rodent populations in check and serve as a food source for other predators including hawks and eagles, scientists say. “We don’t know what will happen if snakes disappear, but there is a concern it could be bad for the ecosystem as a whole,” said Mr. Lorch, who is based in Madison, Wis. Rising snake mortality has been a concern world-wide. A 2010 study by Britain’s Centre for Ecology and Hydrology documented “alarming” declines in 17 snake populations from the U.K. to France, Italy, Nigeria and Australia.

China’s wildlife is vanishing at an alarming clip, a new report has found. The Middle Kingdom’s population of terrestrial vertebrates – including mammals, amphibians, birds, reptiles – has fallen by nearly one half over the past four decades, according to the World Wildlife Fund. That gloomy stat is in keeping with trends around the globe, which saw the number of vertebrates drop by 52% between 1970 and 2010, WWF said. Reptiles and amphibians took the biggest hit during the 1970-2010 period, with their numbers dropping by a staggering 97%. Likewise, numbers of forest mammals—such as musk deer and snub-nosed monkeys—fell by 78%.

Things aren’t looking good for reptiles and amphibians lately, especially frogs. John Alroy at Macquarie University in Australia published a study last month examining recent extinctions for the two groups of animals, and the results are alarming. “About 200 frog extinctions have occurred and hundreds more [frog species] will be lost over the next century, so we are on pace to create a mass extinction,” according to the study. Alroy chose to study reptiles and amphibians partly because “there was a large amount of global data available for these groups, and partly because of a growing concern in the scientific community over the health of frog populations, which are thought to be in a state of decline in many places,” says the Washington Post. Alroy also looked at salamanders, snakes and lizards, but “he found that frogs seemed to be the most vulnerable to extinction—the results suggested that more than 3 percent of all frog species have disappeared, largely since the 1970s,” according to the Washington Post. The findings are especially alarming because the research method known as a Bayesian approach is “highly conservative,” meaning that the estimated number of past and future frog extinctions could, in fact, be even higher.

There is broad concern that a mass extinction of amphibians and reptiles is now underway. Here I apply an extremely conservative Bayesian method to estimate the number of recent amphibian and squamate extinctions in nine important tropical and subtropical regions. The data stem from a combination of museum collection databases and published site surveys. The method computes an extinction probability for each species by considering its sighting frequency and last sighting date. It infers hardly any extinction when collection dates are randomized and it provides underestimates when artificial extinction events are imposed. The method also appears to be insensitive to trends in sampling; therefore, the counts it provides are absolute minimums. Extinctions or severe population crashes have accumulated steadily since the 1970s and 1980s, and at least 3.1% of frog species have already disappeared. Based on these data and this conservative method, the best estimate of the global grand total is roughly 200 extinctions. Consistent with previous results, frog losses are heavy in Latin America, which has been greatly affected by the pathogenic chytrid fungus Batrachochytrium dendrobatidis. Extinction rates are now four orders-of-magnitude higher than background, and at least another 6.9% of all frog species may be lost within the next century, even if there is no acceleration in the growth of environmental threats.

Die Juraviper (Vipera aspis), auch Aspisviper genannt, und die nahe verwandte Kreuzotter (Vipera berus) sind die beiden einzigen in der Schweiz vorkommenden Vipernarten. Die Ringelnatter (Natrix natrix) ist die grösste Schlangenart im Jura und wird im Schnitt etwa einen Meter lang. Die Nahrung der Juraviper besteht vor allem aus Mäusen und Eidechsen. Jedes erwachsene Tier verzehrt pro Saison etwa 120 % seines Körpergewichts, was bedeutet, dass es etwa ein Dutzend grössere Beutetiere pro Jahr verschlingt. Die Hauptnahrung der Ringelnatter sind Frösche, Molche, geschwächte Fische, selten Kröten, Mäuse oder Salamander. Die Juraviper und die Ringelnatter waren in der Region bis zur Mitte des 20. Jh. weit verbreitet. Wie viele andere Tierarten sind sie aber durch Lebensraumveränderungen stark zurückgedrängt worden. Die wärmeliebende Juraviper wird im Baselbiet nur noch sehr selten beobachtet und gilt als vom Aussterben bedroht. Die Ringelnatter kommt noch häufiger vor, doch sind auch ihre Bestände rückläufig und gefährdet.