Amphibians, a unique group of vertebrates containing over 7,000 known species, are threatened worldwide. A 2004 global assessment found that nearly one-third (32%) of the world's amphibians are threatened, representing 1,856 species. Amphibians have existed on earth for over 300 million years, yet in just the last two decades there have been an alarming number of extinctions, nearly 168 species are believed to have gone extinct and at least 2,469 (43%) more have populations that are declining.
Scientists and public health experts are alarmed by the phenomenon, which they suspect to be symptomatic of underlying toxicity in the environment and the food chain. “Missing eyes, deformed hind legs, missing limbs, extra limbs, partial limbs, limbs that are bent or bony, and abnormally thin or weak limbs are some of the reported frog abnormalities in the Western ghats,” said Dr. S. Muralidharan from the Division of Ecotoxicology at Salim Ali Centre for Ornithology & Natural History.
A deadly amphibian disease called severe Perkinsea infections, or SPI, is the cause of many large-scale frog die-offs in the United States, according to a new study by the U.S. Geological Survey. Frogs and salamanders are currently among the most threatened groups of animals on the planet. The two most common frog diseases, chytridiomycosis and ranavirus infection , are linked to frog population declines worldwide. The new study suggests that that SPI is the third most common infectious disease of frogs.
Neonicotinoids are prophylactically used globally on a variety of crops, and there is concern for the potential impacts of neonicotinoids on aquatic ecosystems. The intensive use of pesticides on crops has been identified as a contributor to population declines of amphibians, but currently little is known regarding the sublethal effects of chronic neonicotinoid exposure on amphibians.
Initial assessments that considered these insecticides harmless to aquatic organisms may have led to a relaxation of monitoring efforts, resulting in the worldwide contamination of many aquatic ecosystems with neonicotinoids. The decline of many populations of invertebrates, due mostly to the widespread presence of waterborne residues and the extreme chronic toxicity of neonicotinoids, is affecting the structure and function of aquatic ecosystems. Consequently, vertebrates that depend on insects and other aquatic invertebrates as their sole or main food resource are being affected.
Kiebitze (Vanellus vanellus) gehören zu den absoluten Verlierern, sagt Jutta Over vom Nabu Emsland/Grafschaft Bentheim. Sie sind im Jahr 2017 im Emsland kaum noch zu sehen und stehen wie fast die Hälfte der 140 Brutvogelarten auf der Liste der gefährdeten Arten. Over hat für unsere Redaktion zum heutigen Tag des Artenschutzes eine Liste bedrohter Tiere und Pflanzen im Emsland erstellt. Von den 140 Brutvogelarten im Emsland seien fast die Hälfte auf der Roten Liste Niedersachsens als gefährdet eingestuft, sieben davon sogar vom Erlöschen bedroht.
Wereldwijd gaat het niet goed met amfibieën en infectieziektes zijn een zeer belangrijke factor die achteruitgang en uitsterven van soorten versnellen. Twee van de bekendste amfibieziektes zijn Chytridiomycose en Ranavirus. Beide komen ook in Nederland voor en zorgen lokaal voor de achteruitgang van populaties. Er zijn echter meer ziektes waar amfibieën mee te maken hebben, waaronder Amphibiocystidium-infecties. Amfibieën die zijn geïnfecteerd met soorten uit het genus Amphibiocystidium vertonen wittige tot doorzichtige blaasjes op de huid (<1 cm).
A new study finds that frogs, toads, salamanders and other amphibians in the U.S. are dying off so quickly that they could disappear from half of their habitats in the next 20 years. For some of the more endangered species, they could lose half of their habitats in as little as six years. The nine-year study, published on May 22 in PLoS One by scientists from the U.S. Geological Survey (USGS), examined population trends for 48 species at 34 sites across the country. The researchers found that on average amphibian populations were shrinking a surprising 3.7 percent per year.
A new strain of ranavirus is currently causing mass mortality in several species of amphibian in the Serra da Estrela, the highest mountain range in continental Portugal. This infectious agent is hypervirulent and also affects fish and reptiles, which complicates the situation, according to a study boasting the collaboration of the National Museum of Natural Sciences in Madrid.
Until recently, the Bunderbos was the best place in the Netherlands to find fire salamanders. With tall broadleaf trees shading small streams, the small forest was home to thousands of the 20-centimeter-long creatures, glistening black with bright yellow spots. "It's a very charismatic animal," says Annemarieke Spitzen-van der Sluijs, a conservation biologist with Reptile, Amphibian & Fish Conservation Netherlands (RAVON), a nonprofit group based in Nijmegen. "It's like a dolphin among amphibians, always smiling, with pretty eyes."