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RESPONDENT
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Irina Menyushina
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SITE NAME
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Neizvestnaya River upper reaches, Wrangel Island, Russia
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| Contact details
(phone/fax//e-mail//address): |
| (495)687-06-57 // v.n.ira@mail.ru // Prospect Mira, 103-109, Moscow, 129085, 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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20.05
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24.08
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WEATHER
CONDITIONS
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Weather conditions: |
| The season was late and rainy. A substantial fraction of island area was still snow-covered by the start of bird reproduction. Snow was unevenly distributed, and vast areas in the floodplain of the Gusinaya River, and about 40% of slopes at the west were snow-free in late May. At the east of the island snow-free patches were almost absent in the end of the first 10-day period of June. Birds were short of habitat suitable for reproduction in the central parts of the island. Snowcover reduced to 50% on 22 June and was completely gone on 26 June in course of late, but intensive melt. The river broke up on 13-14 June. Flooding of goose and wader nests and of a nest of Snowy Owl was recorded. Snowfalls were common in late May, early June, July and August. A two-day cold spell in mid August resulted in formation of complete snowcover in tundra, which caused high rise of water in rivers when melted.
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| Date of 50%
snow-cover: |
22.06
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| Date of ice-break on
rivers: |
13-14.06
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| Date of final loss of
snow: |
26.06
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BIOTIC
CONDITIONS
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| Rodents abundance evaluation: |
average
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Breeding conditions:
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Numbers of lemmings, Arctic Foxes and Snowy Owls were average. Most predators bred, and the main study plot of 45 sq.km was populated by 13 pairs of Snowy Owls, 5 pairs of Arctic Foxes, 2 pairs of Pomorine and 8 pairs of Long-tailed skuas. Arctic Foxes occupied about 40% of known dens, and had 5 to 9 pups in broods in August. Reproduction of Pomarine Skuas was unsuccessful, while success of Snowy Owls varied from 0 to 5 fledglings per a pair.
Insufficient supply of lemmings led to a substantial predation pressure on tundra birds, and Snowy Owls were taking not only chicks, but also adult waders. Almost no wader broods or alarming adults were seen on regular excursions at the study plot in August, and only twice fledged young of Long-tailed Skuas were encountered. Thus, reproductive success of tundra birds was low due to shortage of suitable breeding habitats in June and high predation pressure by rodent-specialised predators.
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Rodent dynamics:
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Rodent species recorded:
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Summary
of fauna studies: |
| Field research was focused on ecology and behaviour of rodent-specialised predators on Wrangel Island. Data on spatial structure and reproductive parameters were gathered at a model plot of 45 sq. km. in the centre of island, and on transect counts in its different landscape regions.
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