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RESPONDENT
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Vladimir Pozdnyakov
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SITE NAME
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Lena Delta, southern and eastern parts, Yakutia, Russia
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| Contact details
(phone/fax//e-mail//address): |
| (411-2)33-68-15/(411-2)42-13-72(fax) // vpozd@mail.ru // Kulakovskogo St., 12-59, Yakutsk-7, 677077, Russia
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PROJECT DETAILS |
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Project name:
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Waterfowl monitoring in the Lena River delta
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Start of survey:
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End
of survey: |
Team
size: |
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2.06
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6.08
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3
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WEATHER
CONDITIONS
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Weather conditions: |
| Spring was late and early summer was colder than usual. A single day with mean temperature above freezing was recorded during May (22 May) at the meteorological station "Stolb" in the southern part of the delta (72ø24'N, 126ø48'E), and daily temperatures rised persistently above freezing on 10 June. Generally May and June were 1.5ø and 2.4ø, respectively, colder that average. Flat tundra became 20% free from snow on 5 June, 50% on 10 June, 90% on 16 June and 100% on 20 June in the southeastern part of the delta (72ø11'N, 127ø04'E). Snow covered 50-60% of surface on 25 June in a 20 km-wide belt of coastal tundra in the northeastern part of the delta (72ø52'N, 129ø22'E), where it melted completely by 1 July. Snow and ice retained in pools of polygonal bogs and on low islands until July. Long-lasting snowfalls did not occur in June, but the ones on 5 and 8 June resulted in formation of a continuous snow layer, which however melted during a day. Wind speed reached 7-10 m/s on 5-7, 9-10 and 12 June, while storm wind of 14-20 m/s was recorded on 18-21 June. Ice started to break at average time (7 June) in the southern part of the delta on the Bykovskaya Channel, but was more prolonged (until 18 June) and associated with jams due to low water table.
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| Date of ice-break on
rivers: |
7-21.06
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| Date of final loss of
snow: |
20.06-1.07
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BIOTIC
CONDITIONS
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| Rodents abundance evaluation: |
high
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Breeding conditions:
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Snowy Owls and Pomarine Skuas nested in the eastern part of the delta, where lemmings were abundant, but in lower numbers than in the previous lemming peak year (2000). Clutch size was also lower in Snowy Owls. If lemmings further increase in numbers in 2005 and expand to the western part of the delta, Snowy Owls and Pomarine Skuas will have a chance to breed the second season in a row. Solitary Short-eared Owls were seen several times in the southeastern part of the delta in the first half of June. Breeding numbers of Peregrine Falcons remained stable, while Rough-legged Buzzrds nested in numbers typical for years of low lemming populations even in the southeastern part of the delta. Merlin and Raven bred only in the south of the delta. Although total numbers of Arctic Foxes were not high, they bred and were regularly observed. Ermines were relatively numerous and bred everywhere.
Cold spring and early summer adversely affected reproduction of most birds. Perishing of Little Buntings and Bramblings due to food shortage, wind and cold was observed already during spring migration in the SE delta. We observed 2 Little Stints with ice-covered legs on 5 June, and bodies of 3 Brant Geese, Ruff, Little Stint, Grey Phalarope, Brambling and Willow Warbler were found in late June - early July in the east of the delta. Mass perishing of waders and large gulls was reported from Dunai Island in the northern extremity of the delta by the staff of meteorological station. We got an impression the vagrant forest birds appear in tundra in higher numbers in years with cold spring, e.g., Bramblings and Dusky Thrushes were observed in 2004, as well as in also cold 1996. Other vagrants included Willow Warbler, Siberian Tit and Daurian Redstart.
Waders nested in considerably lower numbers compared with 2003, with the exception of Grey Plover and Turnstone which numbers appeared stable. Nesting density of Sabine's Gull was not affected by the cold spring, but Ross's Gulls bred in a single colony of 4 monitored from 2000. Size of the colonies of Brant Geese under observation decrease by a factor of 2-5 compared with 2003, and most nests were located in the elevated coastal areas of the islands which resulted in circular pattern of nests' spatial arrangement. However, several small colonies ranging from 1-3 pairs were established on islands which had not been used for nesting previously, and in atypical habitats. Nesting numbers of Steller' Eider and King Eider were similar to ones in the previous year. Egg-laying was delayed and prolonged in almost all species of birds.
Predation of clutches in colonies by Arctic Foxes was not observed. Herring and Glaucous gulls and skuas destroyed up to 30% of Brant Goose cluthces during incubation. Wandering and nesting Pomarine Skuas destroyed completely 27.3% and partially 13.6% of Steller's Eider yet incomplete clutches in the beginning of the nesting period. Monitored nests of waders included 8 nests of Turnstone, 6 of Grey Plover, 2 of Dotterel, 6 of Grey Phalarope, 2 of Curlew Sandpiper and 4 of Little Stint, of which a single nest of Turnstone and 2 nests of Grey Plovers were destroyed (apparent nest success 89.3%). This indicates high nest success, but overall reproductive performance of most birds was, probably, low due to low breeding effort caused by poor weather in spring.
Effects of human activities were not significant due to the huge size of the area.
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Rodent dynamics:
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| Lemming numbers were high in the eastern part of the delta, to the east of 127øE.
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Rodent species recorded:
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| Latin | Abundance |
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| Lemmus sibiricus | abundant |
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Summary
of fauna studies: |
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