Vancouver marmot
| Vancouver marmot | ||||||||||||
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Vancouver marmot (Marmota vancouverensis) (preparation) |
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| Marmota vancouverensis | ||||||||||||
| Swarth , 1911 |
The Vancouver marmot ( Marmota vancouverensis ) is a species of the squirrel family that is only native to Vancouver Island . Within the genus of the marmots , the Vancouver marmot is considered to be the species most threatened by extinction. This species is threatened by habitat loss and genetic impoverishment. There was a massive collapse in populations, especially in the 1990s, which led to an intensive program for the conservation of this species being initiated. This includes a breeding program with captive animals and the reintroduction of sustainable populations in appropriate areas.
Appearance
The Vancouver marmot is one of the largest representatives within the genus of marmots. The weight of the animals varies greatly depending on the season. In September, just before the start of hibernation, they weigh up to 6 kilograms. After the end of hibernation their body weight is often only three kilograms.
The fur color of the Vancouver marmot is predominantly a dark chocolate brown. There are isolated white spots on the underside of the body and around the muzzle. There are also isolated white areas of fur on the forehead of the head.
In addition to this white spotting, the Vancouver marmot also has occasional light brown or ocher-colored spots.
Distribution area
Vancouver marmots are restricted in their distribution to Vancouver Island , off the west coast of Canada . At 32,000 square kilometers, this island is the largest island off the west coast of North America . The island has a very mountainous structure. The highest elevations are at 2200 m . Vancouver marmot colonies were found along the entire northwest to southeast trending mountain range. The area populated today is much smaller. There is an isolated colony on Mount Washington and an area 150 square kilometers southeast of Mount McQuillan and Mount Arrowsmith , where several colonies still exist.
Vancouver marmots prefer to colonize south or west facing mountain slopes and prefer altitudes between 1000 and 1400 meters. Due to regular avalanches, there are no trees or bushes here. Only then do the marmots create the treeless meadows they need, where they can find enough grazing.
Stock and causes of the stock decline
In the mid-1980s, the number of Vancouver marmots still found in the wild was estimated at around 350 individuals. When recounted in 1998, a total of 71 Vancouver marmots were counted and the total population estimated at 85 to 95. Out of a total of 25 known colonies, only 13 are still born. The species is therefore extremely threatened. The main cause of the population impact is considered to be habitat loss due to logging and the effects of climate fluctuations.
The marmots initially seem to benefit from logging. Migrating young animals from existing colonies establish new colonies in these regions. However, these colonies fail within a few years if the lack of avalanches ensures that dense vegetation develops here very quickly, in which the first trees are already coming back up. In these areas the marmots do not find the suitable food plants with which they can build up sufficient fat reserves to survive the period of hibernation. It is known that the Alpine marmot prefers to eat the young shoots of plants that are particularly rich in polyunsaturated fatty acids in summer, when there is plenty of food available . These ingredients cannot be generated independently by the mammalian organism. However, a high concentration of essential fatty acids in the white adipose tissue of hibernators enables them to tolerate lower body temperatures during hibernation. In the absence of suitable food plants, marmots are more likely to not survive the winter months due to a lack of warming fat reserves. The lower the fat reserves, the lower the likelihood that the females will bear cubs in the next year. These two mechanisms of action ensure very quickly that colonies in unsuitable habitats go out again.
Another reason for a population decline is discussed that the vegetation on Vancouver Island has changed due to a rise in temperature in such a way that the animals can no longer find enough plants of the species that they need to build up their fat reserves.
Systematics
The Vancouver marmot is closely related to the Olympus marmot ( M. olympus ) and the ice gray marmot ( M. caligata ). The range of the Olympus marmot is the Olympic Peninsula south of Vancouver Island. The ice gray marmot, on the other hand, is native to North American high mountain regions. It is a relatively young species that may have emerged during the last ice age when ice barriers prevented the exchange of individuals.
Human and Vancouver Groundhog
Various measures have been taken in recent years to ensure that the Vancouver marmot continues to exist as a species. Measures include captivity in Toronto and Calgary zoos . Offspring in zoos should ensure that a sufficient number of animals are available in order to have a sufficient number of animals available for reintroduction programs if necessary.
On Vancouver Island attempts are being made to increase and stabilize the number of animals living there within a protected area. Both in captive breeding and in the colonies observed in the field, it should be ensured that inbreeding depression does not occur. Genetic studies have shown that the number of alleles and the degree of heterozygosity in the Vancouver marmot is significantly lower than that of the Alpine marmot. In addition to the lack of suitable habitats, the depletion of the gene pool poses another threat to this species.
One of the mascots for the 2010 Winter Olympics , Mukmuk , represents a Vancouver groundhog.
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literature
- Luise Kruckenhauser, Wilhelm Pinsker , Andrew Bryant: The marmots on Vancouver Island (Marmota vancouverensis, Rodentia Sciuridae): threat to a rare species through habitat loss and genetic impoverishment. In Monika Preleuthner, Gerhard Aubrecht (ed.): Murmeltiere (= catalog of the Upper Austrian National Museum. NF # 146 =. Stapfia. Vol. 63). Biology Center, Linz 1999, ISBN 3-85474-044-1 , pp. 159–168, PDF (1 MB) on ZOBODAT
- Monika Preleuthner, Gerhard Aubrecht (Ed.): Marmots (= catalog of the Upper Austrian State Museum. NF No. 146 = Stapfia. Vol. 63). Biology Center, Linz 1999, ISBN 3-85474-044-1 , online at ZOBODAT
Individual evidence
- ↑ Kruckenhauser, Pinsker, Bryant: The marmots on Vancouver Island (Marmota vancouverensis, Rodentia Sciuridae): threat to a rare species through habitat loss and genetic impoverishment. In: Preleuthner, Aubrecht (Ed.): Marmots. 1999, p. 160.
- ↑ Kruckenhauser, Pinsker, Bryant: The marmots on Vancouver Island (Marmota vancouverensis, Rodentia Sciuridae): threat to a rare species through habitat loss and genetic impoverishment. In: Preleuthner, Aubrecht (Ed.): Marmots. 1999, p. 161.
- ↑ Kruckenhauser, Pinsker, Bryant: The marmots on Vancouver Island (Marmota vancouverensis, Rodentia Sciuridae): threat to a rare species through habitat loss and genetic impoverishment. In: Preleuthner, Aubrecht (Ed.): Marmots. 1999, p. 160.
- ↑ Ute Bruns, Fredy Frey-Roos, Thomas Ruf, Walter Arnold: Food ecology of the Alpine marmot (Marmota marmota) and the importance of essential fatty acids. In: Monika Preleuthner, Gerhard Aubrecht (Hrsg.): Marmots. In: Stapfia. Volume 63, Linz 1999, pp. 57-66, PDF (950 kB) on ZOBODAT
- ^ Kruckenhauser, Pinsker, Bryant: The marmots on Vancouver Island (Marmota vancouverensis, Rodentia Sciuridae): threat to a rare species through habitat loss and genetic impoverishment. In: Preleuthner, Aubrecht (Ed.): Marmots. 1999, p. 163.
- ^ Kruckenhauser, Pinsker, Bryant: The marmots on Vancouver Island (Marmota vancouverensis, Rodentia Sciuridae): threat to a rare species through habitat loss and genetic impoverishment. In: Preleuthner, Aubrecht (Ed.): Marmots. 1999, pp. 165-166.
- ↑ Meet the 2010 Olympic mascots. Canwest Publishing , January 9, 2009, accessed October 10, 2012 .
Web link
- Marmota vancouverensis inthe IUCN 2013 Red List of Threatened Species . 2. Posted by: Nagorsen, DW & NatureServe (Cannings, S. & Hammerson, G.), 2008. Retrieved December 21, 2013.
- You have to starve to survive