In the late nineties, sudden mass mortalities in amphibian populations from pristine or protected areas were observed. Habitat destruction, alteration and fragmentation, commercial over-exploitation for pet-trade and food, introduction of non-native species, infectious diseases and climate disturbance have been identified as stressors of decline. According the latest assessment of the IUCN Red List of Threatened Species (update 2015) at least 41% of all extant amphibian species is at risk of extinction. Furthermore, we pinpoint areas in which more detailed studies are necessary or which have not received the attention they merit.Īmphibians worldwide are dwindling both in numbers and distribution area.
#Second extinction golden egg skin#
salamandrivorans with the host’s skin are integrated. With this review we aim to provide the reader with a state-of-the art of host-pathogen interactions for both fungi, in which new data pertaining to the interaction of B. Other striking differences between both fungi include gross pathology and thermal preferences. salamandrivorans it is limited to European salamanders. dendrobatidis is mainly limited to Australian, neotropical, South European and West American amphibians, while for B. salamandrivorans seems limited to urodeles.
dendrobatidis infects the skin of a large range of anurans, urodeles and caecilians, whereas to date the host range of B. The clinical outcome of infection is highly dependent on the amphibian host, the fungal virulence and environmental determinants. Not all amphibians respond equally to infection and host responses might range from resistant, over tolerant to susceptible. The skin disease caused by these fungi is named chytridiomycosis and affects the vital function of amphibian skin.
#Second extinction golden egg drivers#
Infectious drivers of these declines include the recently emerged fungal pathogens Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans (Chytridiomycota). This has played a large part in the recovery of some species.Amphibian declines and extinctions are emblematic for the current sixth mass extinction event. A voluntary withdrawal of the pesticides began in 1962, with a total ban in place by 1982. Peregrines fell to 360 pairs in Britain by 1963, largely because of pesticide poisoning. Peregrines and sparrowhawks were particularly affected by organochlorines. This caused severe problems of eggshell thinning and increased adult and chick mortality. These pesticides were able to persist in the environment for a long time and were soluble in fat, allowing them to accumulate up the food chain, concentrating in top predators such as birds of prey. Organochlorine pesticides were widely used in agriculture throughout the 1950s and '60s.
The introduction of myxomatosis in 1955 to control the rabbit population contributed to declines in buzzards, and many birds of prey were poisoned by organochlorine pesticides such as DDT, leading to widespread declines. However, killing by game managers increased again at the end of the wars, and peregrines were killed on government orders to protect carrier pigeons during the Second World War. Less destruction occurred, and some species like the sparrowhawk increased in numbers. By the end of the First World War, five of our 15 breeding birds of prey (goshawk, marsh harrier, honey buzzard, white-tailed eagle and osprey) had been driven to extinction in the UK.įive more species (golden eagle, hobby, hen harrier, red kite and Montagu's harrier) all declined to fewer than 100 pairs at some stage between the 1870s and 1970s.ĭuring the World Wars, gamekeeping declined as keepers went off to fight.
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