Throughout the past decade, valuable strides have been made in the studies of tiger health and recovery. A major finding in tiger health research occurred in 2001, when WCS field veterinarians and molecular scientists were first to genetically characterize and discover the presence of canine distemper virus (CDV) in the rare Amur tiger (also known […]Read more...
Throughout the past decade, valuable strides have been made in the studies of tiger health and recovery. A major finding in tiger health research occurred in 2001, when WCS field veterinarians and molecular scientists were first to genetically characterize and discover the presence of canine distemper virus (CDV) in the rare Amur tiger (also known as the Siberian tiger). Now WCS teams are expanding their studies to better understand how the disease is spread to tigers and might impact the larger population.
Canine distemper virus is the second most common cause of infectious disease death in domestic dogs, but also poses a significant threat to endangered and non-endangered wildlife around the globe. With the pressures of habitat loss, poaching, depletion of prey species, and CDV, WCS scientists and conservationists remain tireless in their efforts to combat these risk factors and protect and grow the remaining tiger population.
It is now understood that canine distemper virus tragically causes abnormal behaviors among tigers before eventually killing them. This is a distressing realization because there are likely no more than 3,500 tigers left in the wild, and all of the living subspecies are currently listed as Endangered by the International Union for the Conservation of Nature. Specifically, the Amur tiger is among the most endangered cat species on the planet, with only 400-500 individuals left across their range in the Russian Far East and China.
Since the discovery of distemper among Amur tigers, WCS has participated in further studies to delve into various transmission scenarios and impact. One study involves extracting genetic information from archived tiger tissue as well as from a variety of species in their territory. These samples are being tested and compared with the intent of pinpointing the most likely sources of infection among wild tigers. This testing is crucial in understanding the risk that the virus represents to wild tigers and local communities, and in developing methods to managing this risk, such as through the design of targeted oral vaccination programs.
WCS also participated in a study which extrapolates known CDV metrics to the larger tiger population. While the illness has been shown to lead to the deaths of individual tigers, its long-term impacts on tiger populations had never before been studied. The authors evaluated impacts on the Amur tiger population in Russia’s Sikhote-Alin Biosphere Zapovednik (SABZ), where tiger numbers declined from 38 individuals to 9 in the years 2007 to 2012. In 2009 and 2010, six adult tigers died or disappeared from the reserve, and CDV was confirmed in two dead tigers—leading scientists to believe that the disease likely played a role in the overall decline of the population. Using models, scientists were able to simulate the effects of the infection on isolated tiger populations of various sizes through various transmission scenarios. The study found that smaller populations of tigers are more vulnerable to extinction by CDV. Populations consisting of 25 individuals were 1.65 times more likely to decline in the next 50 years when the distemper virus was present. This was an alarming finding given that more than half the world’s tigers in 2010 were limited to populations of less than 25 individuals.
The results are alarming, but will allow teams to plan conservation strategies that address the finding and design new conservation approaches.
While canine distemper virus has presented an additional concern in tiger repopulation efforts, WCS has seen great success in the reintroduction of orphaned and rehabilitated tiger cubs back into the wild. In the spring of 2014, five young tigers were released into the wilderness of the Russian Far East as part of WCS’s effort to recolonize lost Amur habitat.
As studies increase our knowledge of the threats facing tigers and reintroduction efforts show success there continues to be greater hope for the overall survival of the species.
Volcanoes can have multiple personalities, peaceful one minute, explosive the next. A geologist who has untangled these complicated states on land and at sea, improving our ability to see deadly eruptions coming, will receive the 2015 Vetlesen Prize. Stephen Sparks, a volcanologist at the University of Bristol, will be awarded a medal and $250,000 at […]Read more...
After finishing his PhD in 1974, Sparks worked with colleagues to model eruptive processes during stints at Lancaster University in Britain and the University of Rhode Island. In a 1977 study inNature, he showed how magma deep within the earth could mix with material closer to the surface to trigger an explosive eruption. Working with physicist Lionel Wilson, he explained how explosions sometimes shoot ash high into the stratosphere, but at other times unleash deadly flows of ash and gas down the flanks of volcanoes. He went on to show in Icelandic volcanoes that the sideways flow of magma could cause the spectacular collapse of a caldera up to 40 miles away. Off the coast of Greece, his analysis of deep-sea volcanic rocks added support for the idea that the Thera eruption around 1500 BC may have influenced the fall of the ancient Minoans on the island of Crete.