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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: |
| Winter 2000-2001 was windy and amount of snow accumulated by the end of May was low: 10-20 sm on flat areas, which made terrain character easily recognizable. In the end of the third week of May snow cover was still 100% almost everywhere, while air temperatures changed from -15-17øC at night to -7-8øC at day-time. In the last week of May air temperatures increased 15 degrees during two days, and snow cover has been destroying rapidly. Unusually warm weather in late May - early June resulted in rapid snow melt on the territory of main geese colony, when geese did not arrive yet.
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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: |
average
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Breeding conditions:
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Arrival and start of geese reproduction were delayed one week compared with development of spring events. Egg-laying in the main-colony started when air temperature was reaching +11.5øC, while mass arrival of geese to the colony, which normally happened on the date of stable raising of air temperatures above freezing, and mass nesting occurred at maximal temperatures reaching +15.5øC. This situation was never observed on the Wrangel Island in the last 30 years.
Relatively high lemming numbers in some areas favoured nesting of Snowy Owls and related to the latter expansion of Snow Goose nesting range. Approximately 2000 geese pairs nested outside of the main colony in 2001, with principal stimulated by owls concentrations in traditional areas in the upper reaches of the Neizvestnaya River and valley of the Mamontovaya River in its middle reaches.
Around 24,000 nests were initiated in the colony in valley of the Tundrovaya River. Despite participation in reproduction of young birds 2-4 years old, dropping eggs to nests of other birds and outside nests was almost never observed, due to abundance of suitable for nesting territory. A ubstantial fraction of young birds among breeders and difficult spring migration were, probably, responsible for insignificant decrease of average clutch size.
Weather conditions were favourable during the first half of incubation, but one week before hatching air temperatures dropped and night frosts were recorded. Hatching and departing of broods from the colony coinsided with the period of maximal summer temperatures and very dry weather. Approximately 90% of broods were leaving the colony and heading to the Tundra of Academy along the Tundrovaya River in very dry conditions, when rivers became shallow and many streams dried up.
Five pairs of Arctic Foxes bred in the main colony and its vicinity, but level of their activities in the colony and impact on geese was low, and on some days none would appear during 6-8 hours of observations. Death of adult birds from diseases was recorded on the colony, and many bodies were remaining intact for a long time, which also indicated low level of predators' activities. Brood-raring in geese was not affected by anything particular on the part of either predators, or weather. Geese departure from the island was early, as cold weather came early.
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Rodent dynamics:
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| Rapid increase of temperature and associated snow melt caused increased surface activity of lemmings. High numbers of lemming ventilation holes in snow (541 per 16 km) and high abundance of Pomarine Skuas created an impression of very high rodent numbers. However, lemming numbers in the area of the main geese colony were visually evaluated as average after snow melt. Lemmings inhabited northern (Tundra of Academia) and western (Gusinaya River valley) parts of the island in low numbers, and some localities in center and on the south - in high numbers.
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Rodent species recorded:
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Summary
of fauna studies: |
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