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SITE NAME
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Cape Vostochny, Piasina delta, Taimyr, Russia
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| Contact details
(phone/fax//e-mail//address): |
| +31 317 478729/+31 317 419 000 (fax) // bart.ebbinge@wur.nl // Alterra, PO Box 47, NL-6700AA, Wageningen, The Netherlands
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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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5.06
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14.08
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23
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WEATHER
CONDITIONS
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Weather conditions: |
Spring was very late, and an unusual amount of snow had accumulated. Snow covered 100 % of the tundra on 5 June 2008 with very deep snow. Snowcover was reduced to 50 % by 26 June and had finally completely melted by 10 July. Most ice disappeared from the Lidia Bay on 7 July, but Bird Islands and large island Farwaterniy were much longer surrounded by strong ice, which allowed Arctic Fox from Farwaterniy to visit these islands and cache eggs of Brent Geese and Taimyr gulls until 11 July.
From 4 June till the end of July the wind was mainly from a northerly direction and temperatures were low. Minimum temperature was -6°C on 8 June and the maximum temperature +21°C on 25 July. Between 4-30 June the mean temperature was 0.9°C, minimum -5.8°C and maximum + 9.7°C. From 1-31 July the mean temperature was +6.3°C, minimum -1.8°C and maximum + 21.3°C. In August between 1-14 August the mean temperature was +8.4°C, minimum +6.7°C and maximum +19.1°C. Apart from some snowfall in early June there was hardly any precipitation. The tundra was very dry in the end of July. In early August the wind changed to the south and higher temperatures were reached. On 3 and 4 July the melting water reached its highest level (about one week later than usual). The large amount of snow resulted in such a high water level in spring that several low-lying islands in the Pyasina Delta (e.g., Verkhny Island and Beacon Islands) were flooded on 3 July resulting in complete losses of many clutches of Brent Geese, gulls and divers.
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| Date of 50%
snow-cover: |
26.06
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| Date of ice-break on
rivers: |
7.07
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| Date of final loss of
snow: |
10.07
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BIOTIC
CONDITIONS
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| Rodents abundance evaluation: |
average
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Breeding conditions:
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Arctic foxes were seen regularly. Two fox dens were occupied by breeding foxes. One with 10 cubs and one with at least 5 cubs. Two dead foxes in winter fur were found after the snow had melted. One Wolf was seen eating an Arctic Fox on the ice-covered Lidia Bay, and in early August was observed near our camp. After the snow had melted also one dead Polar Bear (young female of about 100 kg)) was found. Least Weasels were regularly observed initially, but most seemed to have disappeared by early August. The occurrence of Least Weasels also indicates that lemmings must have been abundant during the preceding winter.
Snowy Owls were present and observed regularly early in the season, but less so in July and August. Snowy Owls did not nest. Rough-legged Buzzards were seen even less, and also did not nest. Pomarine Skuas were very abundant on the tundra till mid July, but only one nest was found. Two nests of Long-tailed Skuas were found, but both were predated.
Waders started to nest extremely late, and predation rate was quite high.
The daily nest survival was 91.16%, which means that over a 21-day nesting period nest survival is only 14%. 40 nests were predated out of 62 nests found and checked more than once. Surprisingly Pacigfic Golden Plovers and some Grey Plovers still nested or re-nested very late and managed to hatch some chicks in early August. The last Grey Plover chicks hatched and were ringed on 2 August. The last Pacific Golden Plover chicks hatched and were ringed on 12 August. In case of the Grey Plover this was quite surprising, because we rarely observed Grey Plovers on the tundra after mid July, whereas Pacific Golden Plovers kept displaying until late in the season.
In August some larger flocks of Dotterels (up to 35 birds) were observed on migration.
Geese did very poorly. Very few nests of White-fronted Geese were found, and though at least one nest hatched successfully, later not a single brood was observed of this species. Brent Geese did only somewhat better on Bird Islands, and some nests survived until hatching. Only some families with small goslings were seen, but by early August all goslings had disappeared. Red-breasted Geese, though low in numbers, did remarkably better and managed to raise some goslings on Bird Islands.
Taimyr Gulls did lay eggs, but predation pressure was so heavy, even by conspecifics, that only very few chicks survived. Just like in 2007 Glaucous Gulls were somewhat more numerous than in the years 2004, 2005 and 2006, and also more successful than Taimyr Gulls.
Among the passerines in particular Lapland Buntings were very abundant, and even though quite a number was predated (a.o. by Arctic Foxes, and presumably also by Weasels, Taimyr Gulls and skuas). 28 nests of Lapland Buntings were found and checked more than once. Twelve of these were predated during egg-phase, and daily nest survival rate was 94,6%. In 14 of these 28 nests eggs hatched. Parents managed to raise their offspring until fledging in 16 of 19 Lapland Bunting nests with chicks. Snow Buntings nesting in the stony areas, did less well than Lapland Buntings and suffered a lot from predation by Least Weasels. Shorelarks also managed to raise some chicks till fledging, and also a few nests of grouse all hatched successfully. Altogether the daily nest survival of the songbirds was 93,89%, and thus considerably higher than for the waders. Red-throated Pipits were only rarely seen in 2008, and were not found nesting.
Moult migration of White-fronted Geese from the west in early July was much less intensive than in previous years, and also our standard survey in the Pyasina delta yielded only half the number of moulting White-fronted Geese. In 2006 92,000 moulting White-fronted Geese were counted on this standard survey of 89 km of streams, whereas in 2008 only 39,000 were counted here.
Only about 10 moulting Bean Geese were counted during this survey.
No moulting Barnacle Geese were observed in 2008. The number of only 4,000 moulting Brent Geese on Bird islands (including the Beacon Islands) was also much lower then in previous years.
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Rodent dynamics:
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| Spring was very late, and numerous Siberian Lemmings were recorded on first snow-free patches, which indicated their high abundance during the previous winter. These lemmings were immediately captured by Arctic Foxes and Least Weasels, as well as by abundant non-breeding predators (Snowy Owls, skuas and gulls). By the start of trapping on 27 June lemming numbers dropped dramatically, and their density per 100 trap-nights was evaluated as 1.25 Siberian Lemmings and 0.25 Collared Lemmings. Counts on plots yielded density 4 Siberian Lemmings per 1 hectare. All captured females were either already having bred in this season, or pregnant, and juvenile lemmings were seen in tundra in early August.
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Rodent species recorded:
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| Latin | Abundance |
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| Lemmus sibiricus | common |
| Dicrostonyx torquatus | rare |
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Summary
of fauna studies: |
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