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RESPONDENT
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Mikhail Soloviev
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SITE NAME
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Verkhnyaya Taimyra River mouth, central Taimyr Peninsula, Russia
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| Contact details
(phone/fax//e-mail//address): |
| (495)9394424 // mikhail-soloviev@yandex.ru // Dept. of Vertebrate Zoology, Biological Faculty, Moscow State University, 119992 Moscow, Russia
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PROJECT DETAILS |
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Project name:
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Wader Monitoring Project on Taimyr
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Start of survey:
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End
of survey: |
Team
size: |
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19.06
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4.08
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4
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WEATHER
CONDITIONS
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Weather conditions: |
| Spring was early in 2005, and we estimated 9 June as a date of snow melt on 50% of the flat tundra surface. The tundra cleared completely and ice on rivers broke up before our arrival on 19 June. Temperatures were average in July, while amount of precipitation was higher than usual in the second half of the month. Extreme events were not recorded, but the weather turned cold after 20 July when temperatures dropped to +1.5øC on some days and rains were common.
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| Season temperature: |
average
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| Date of 50%
snow-cover: |
9.06
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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: |
high
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Breeding conditions:
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Number of inhabited dens of Arctic Foxes increased from 2 in 2004 to 7 in 2005 in the study area of approximately 86 km2, and they bred successfully. Several observations of the Least Weasel were made in late June - early July in the camp vicinity. Two wolves moved through the study area on 25 July following migrating reindeers in the general south-westerly direction.
Snowy Owls and Pomarine Skuas did not nest in 2004, while 3 nests of the former species were found within a study area of 86 km2 in 2005. Clutches contained 4 and 7 eggs in two nests found before and during hatching, and chicks hatched successfully in all nests. Pomarine Skuas nested at a density 0.77 nest/km2, and occurred in similar numbers across different landscapes. A single nest was predated of 15 monitored, while 14 survived to hatching. Numbers of breeding Long-tailed Skuas and their nest success increased in 2005 compared with the previous year, while Arctic Skuas bred at a very low numbers and only in alluvial landscape in both seasons.
A single nest of Peregrine Falcons in the area contained a clutch of 3 eggs and successfully survived to hatching. Numbers of Rough-legged Buzzards increased from 6 pairs in the area of 86 km2 in 2004 to 8 pairs in 2005, and their clutch size increased significantly in this species from 3.00ñ0.63 (lim 2-4, n=6) in 2004 to 4.86ñ0.69 (lim 4-6, n=7) in 2005. All nests found during incubation in 2005 survived to hatching.
The abundance of Arctic Hares remained very high in 2005. In spite of much earlier spring phenology in 2005 compared with 2004 mass migration of reindeers has started on 22 July 2005, at a delay of 4 days compared with the previous year. The migration was less intensive in 2005, as we observed herds of 100s moving to the south-west during several days which was approximately an order of magnitude lower numbers than in 2004. Trampling of eggs was not recorded in 2005 in contrast to 2004 when approximately 30% of nests with eggs remaining by the time of mass migration had been trampled by reindeers.
Thus, high numbers of lemmings resulted in successful nesting of rodent-specialists (Snowy Owls and Pomarine Skuas), while Arctic Foxes, Long-tailed Skuas and Rough-legged Buzzards responded by increased reproductive effort and nest success.
Birds started breeding early in 2005 with the following first egg dates back-calculated from hatching dates: 11 June in Dunlin, 12 June in Curlew Sandpiper and Little Stint, 13 June in Pacific Golden Plover and Lapland Bunting, 15 June in Grey Plover and Grey Phalarope, 16 June in Long-tailed Skua and 17 June in Pomarine Skua. Start of nesting in Pectoral Sandpiper and Ruff was considerably delayed compared to other species of waders, with clutch initiation on 21 and 28 June respectively.
Total density of waders increased in 2005 compared with 2004 from 53.5 to 100.1 nest/km2 in the terrace plot and decreased from 149.3 to 90.4 nest/km2 in the floodplain plot. Distribution of breeding birds between main landscapes became more even in the area compared with the previous late season, presumably due to early snowmelt in 2005 and associated availability of bogs for nesting. Little Stint and Grey Phalarope were the most abundant species of waders in 2004 and 2005.
Breeding records of White-billed Diver, Spotted Redshank and Long-billed Dowitcher in the area expanded ranges of these species northwards. An observation of Barnacle Goose in a flock of 11 White-fronted Geese on 30 June was the first record of the species on the Taimyr Peninsula, approximately 1350 km to the north-east of the breeding grounds on the Yugorsky Peninsula.
Apparent nest success was 51.5% (n=136) and 59.7% (n=144) in waders, and 64.0% (n=25) and 85.5% (n=62) in other non-passerine birds in 2004 and 2005, respectively. In 2005 nest success was average in Pacific Golden Plover (58.3, n=12) and Grey Plover (64.3, n=14) which represented a considerable improvement compared with nest survival below 20% in 2004. Nesting was very successful in Dunlin (100.0%, n=10), Little Stint (67.6%, n=37) and Grey Phalarope (80.0%, n=20), while success of Pectoral Sandpiper and Ruff decreased dramatically from 77.8% (n=9) to 23.5 (n=17), and from 66.7% (n=12) to 12.5 (n=8), respectively. Late breeding of two latter species could have resulted in their inferior breeding performance, because pressure of abundant avian predators increased in accordance with the decrease of lemming abundance in July.
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Rodent dynamics:
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Lemmings numbers were high, and 4 observers recorded 725 lemmings in total during study period from 19 June to 4 August. The numbers of lemming records per observer-day was the record high in 2005, and exceeded by approximately a factor of 1.5 the second highest value since 1994 recorded in 2000. Number of rodent observations was rapidly growing from 20-24 June, than dropped to average values and produced the second smaller peak in early July. Lemming were still common during July, but they were not recorded daily, and the abundance increased again in the last days of July-early August.
Siberian Lemmings predominated among animals which species was identified, while Collared Lemmings contributed only 1.37% of all encounters. On completion of snowmelt, on 21 June, lemming undersnow nests were counted on a transect, located on the slopes of the first river terrace and watershed slopes. A density of 3.25 nest/km was much lower than could have been expected based on the numbers of rodents recorded in summer, given that the nest density was 7.1 per km in 2000 with lower rate of summer visual records.
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Rodent species recorded:
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| Latin | Abundance |
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| Lemmus sibiricus | abundant |
| Dicrostonyx torquatus | rare |
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Summary
of fauna studies: |
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