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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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29.05
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24.07
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5
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WEATHER
CONDITIONS
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Weather conditions: |
Spring was earlier and warmer than average in the area. According to the data of the weather station "Stolb" in the south of the delta (72ø24'N, 126ø48'E) mean daily air temperature was 0.8øC and 1.7øC abobe the long-term average in May and June, respectively. Mean daily air temperature reached +2øC on 24-25 and 29 May. Temperature consistently rose above freezing on 6 June which is close to long-term average. The period from 10-20 June was the warmest in June, with mean daily air temperatures reaching +17.8øC and mean temperature for the period 5.2øC above long-term average. The last 10 days of June were 2øC colder than usual. Snow cover reduced to 50% by 29 May, 90% by 1 June on level areas in the southern and south-eastern parts fo the delta, and completely disappeared by 5 June. Strong snowfalls occurred on 9 and 11 June, and snow blanketed the ground with a layer 5 cm thick, but melted on the next day. High tide in the seaside parts of the delta was caused on 13 July by strong winds and resulted in flooding of replacement clutches of Temminck's Stints and Arctic Terns on small islands of low floodplain.
The timing of ice-break was average, and it developed quickly from 9-17 June at an average water level. The south-easternmost channel of the delta, Bykovskaya, cleared from ice in 3 days (8-10 June). Parts of channels closest to the sea cleared by 18 June.
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| Date of 50%
snow-cover: |
29.05
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| Date of ice-break on
rivers: |
9-17.06
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| Date of final loss of
snow: |
5.06
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BIOTIC
CONDITIONS
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| Rodents abundance evaluation: |
low
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Breeding conditions:
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Arctic Foxes were rare, their breeding and events of predation on bird clutches were not observed. Non-breeding Pomarine Skuas concentrated in June in a 20-30 km coastal belt of the delta where lemmings were present during snowmelt, but most of skuas departed in early July. Long-tailed Skuas bred, while numbers of Arctic Skuas were lower than in the previous years and their breeding in the surveyed parts of the delta was not confirmed, although they could have bred elsewhere. Solitary non-breeding Snowy Owls were observed from time to time, and a Short-eared Owl was recorded on 2 June in the south of the delta. Rough-legged Buzzards nested only in the south of the delta at a typical density for years of low lemming abundance. Breeding abundance of Peregrine Falcons was stable. The first confirmed breeding record of Ravens was made in the south of the delta.
The weather was favourable for birds, and they arrived earlier than average. Most species of waterbirds were already present in the delta by early June. A vagrant Barn Swallow was observed in the south of the delta on 14 June. Abundance of waterbirds was high on plots and transects during prenesting period, but only geese and swans nested successfully. Breeding numbers of Brent Geese, Bean Geese, White-fronted Geese and Bewick's Swans were the record high for the whole period of studies. However, nest success of Brent Geese was the lowest (62.3%) on record for 8 years due to predation by skuas and large gulls. A single nest of White-fronted Geese of 7 under observation was destroyed.
Ducks, Sabine's and Ross's gulls nested at a very low density in coastal parts of the delta due to high abundance and strong predation pressure by Pomarine Skuas, Glaucous and Herring gulls. All nests of ducks and small gulls were destroyed and mostly at a stage of egg-laying. All nests of Steller's Eiders in their typical habitat, polygonal bog, failed, as well as found there nests of King Eiders, Sabine's Gulls, Arctic Terns and a single found nest of Baikal Teal. Bird nesting was more successful in colonies of Brent Geese on small isolated islands. Some Steller's Eiders probably laid replacement clutches, as we found 3 nests with 1, 2 and 4 eggs in mid July. Two of these nests were situated in an atypical habitat - low willow stand on a periphery of the Brent Geese colony.
Most nests of waders on large and medium-sized islands were destroyed, with overall nest success 20.3% on the main plot. Apparent nest success was 0% in Grey Plover (n=1), 33.3% in Pectoral Sandpiper (n=3), 33.3% in Turnstone (n=3), 26.3% in Red Phalarope (n=19), 0% in Curlew Sandpiper (n=2), 20% in Little Stint (n=15) and 11.5% in Temminck's Stint (n=26). Most nests of waders survived on small isolated islands, in particular, those with Brent Geese colonies, although available scarse data resulted in a value of nest success (90.5%, n=21) that appears to be an overestimate.
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Rodent dynamics:
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| Lemming abundance was low in 2006, following a two-year period of high numbers. Lemmings were recorded only during snowmelt in a 20-30 km coastal belt of the delta.
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Rodent species recorded:
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Summary
of fauna studies: |
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