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RESPONDENT
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Vasili Baranyuk
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SITE NAME
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Tundrovaya River valley, Wrangel Island, Russia
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| Contact details
(phone/fax//e-mail//address): |
| (095)441-12-16 // vvbar@vvbar.msk.ru // Lomonosovsky Pr., 35-40, Moscow, Russia
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PROJECT DETAILS |
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Start of survey:
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End
of survey: |
Team
size: |
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WEATHER
CONDITIONS
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Weather conditions: |
| Prolonged warming with heavy rains in the second half of October 2004 resulted in formation of thick ice on the tundra. Snow accumulation was low during winter. The spring of 2005 was characterized by early snow melt with warm late May and June, cool July, warm August and September. In general weather was dry during breeding season 2005 on Wrangel Island.
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| Date of ice-break on
rivers: |
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| Date of final loss of
snow: |
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BIOTIC
CONDITIONS
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| Rodents abundance evaluation: |
low
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Breeding conditions:
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Numbers of Snowy Owls were low and they did not breed. Survival of Reindeers was low during winter 2004-2005, maim mortality occurring in the second half of winter. Thousands of Reindeer carcasses were found on Wrangel Island in 2005, and approximately 1500-2000 individuals of about 7500 survived to spring.
Numbers of Arctic Foxes on the island were low, as many of them died during winter. The sea around Wrangel Island did not freeze until mid November and Arctic Foxes had to stay on the island. Low lemming abundance after October rains resulted in shortage of food in the first half of winter and perishing of many foxes prior to appearance en masse of reindeer bodies. Breeding activity of Arctic Foxes was very low, and we found only 4 litters on the whole Wrangel Island and a single one at the Tundra River Colony.
Breeding phenology of Snow Geese was 4-5 days earlier that average in 2005. First nests were initiated on May 26 at the Tundra River colony, and the peak of nest initiation occurred on 29-31 May. Mean clutch size was 4.16ñ0.12 (n=123) at the Tundra River colony in 2005. Less that five hundred eggs were abandoned in the colony (approximately one egg per 100 nests). About 200 000 eggs were produced by geese at the Tundra River colony in 2005, of which about 145 000 (72.5%) survived to hatching. Hatching started on 24 June in geese, which was earlier than the average for the period from 1970, June 27. The peak hatching occurred on June 26-28. The first broods started to leave the colony on 25 June, as in 2004, moving to the north plain of the Tundra of Academy. Majority of broods followed the Tundra River, because the tundra was dry elsewhere due to low precipitation in summer. Mixing-up of broods occurred at this time, and approximately 5% of pairs with broods adopted goslings from different broods. A record number of goslings in a brood at this time was 17, while mean brood size just after leaving the colony was 3.78ñ0.08 (n=480). 5.5% of all families consisted from 7 or more goslings, and these large broods included 23.6% of all goslings. Mixing-up of broods can represent a mechanism of gene exchange between two populations of Snow Geese on Wrangel Island.
The area of the Tundra River colony did not change considerably in 2005 compared with the last 15 years. However, the high density of 48 000 nests in 900 ha was revealed using ground transect counts. Nesting success (proportion of nests hatching at least one egg) was high (82.3%) in 2005, but activity of predators was high too. There were about 8500 unsuccessful nests. Numbers of Arctic Foxes were below average, but not low in the colony. Glaucous Gulls occurred in high numbers, up to 100 birds at a time. Similarly to the situation in 2004 three adult males of muskoxen visited the colony and were flushing incubating geese from nests, which resulted in depredation of eggs by Glaucous Gulls. Apart from traditional predation by Arctic Foxes and Glaucous Gulls, goose nest were also destroyed in 2005 by Wolverine. The number of Wolverines has increased on the Wrangel Island in recent years, and they became regular visitors to the goose colony.
We observed a family of geese departing from the colony on June 29 in which male belonged to dark blue phase and female was white. This pair led 4 goslings: two dark and two light.
Breeding number of Snow Geese outside of the Tundra River colony did not exceed 200 pairs across Wrangel Island. They nested in association with territorial Snowy Owls, but we did not find nests of the latter species.
Goose families occupied the whole Tundra of Academy and even north-eastern part of the island by mid July, at about two weeks time after the peak of hatching at the Tundra river colony. Goslings had to move at a distance exceeding 120 km after hatching. Snow Goose families were everywhere in this part of the island. Numbers of predators were low (about one Arctic Fox per 100 km of survey) in the Tundra of Academy which favoured survival of goslings even in large families. Mean brood size was 3.25ñ0.14 (n=307) before departure of geese from Wrangel Island in August, while the largest family consisted from 31 (!) gosling. 4.9% of all families consisted from 7 or more goslings, and these large broods included 16.8% of all goslings. This indicated very low impact by predators on survival of goslings during this period.
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Rodent dynamics:
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| Numbers of lemmings were very low in all part of Wrangel Island in 2005, which was also due to their low survival following thaws and icing in October 2004.
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Rodent species recorded:
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Summary
of fauna studies: |
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