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RESPONDENT
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Pavel Tomkovich
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SITE NAME
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Neizvestnaya River, middle reaches, Wrangel Island, Russia
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| Contact details
(phone/fax//e-mail//address): |
| (495)6294474/(495)629-48-25(fax, for P. Tomkovich) // pst@zmmu.msu.ru // Zoological Museum, Bolshaya Nikitskaya St., 6, Moscow, 125009, 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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5.07
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14.08
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WEATHER
CONDITIONS
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| Season phenology: |
average
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Weather conditions: |
Snow accumulation was high during the winter 2006/2007. Accordingly there were winter conditions when the first birds arrived. Snow Buntings appeared on 16 April in the Ushakovskoe settlement, Glaucous Gulls and Black Guillemots on 21 April at coastal rocks on the east of the island, Snow Geese on 19 May in inland tundra, Red Knot on 22 May, Lapland Buntings on 24 May, Turnstones and Pectoral Sandpipers on 25 May, Grey Plovers on 26 May, Dunlins and Arctic Redpolls on 28 May, Long-tailed Skuas and Sabine's Gulls on 30 May. By the time of start of melting the tundra surface was almost 100% snow covered in the area of the "Middle Neizvestnaya" field station. Rapid warming in the end of May led to intensive snow melt. Ice on islands in the rivers (Gusinaya, Tundrovaya and Neizvestnaya) broke simultaneously on 1 June. This resulted in a very high flood with water levels reaching record high values compared with previous years in the station area. The water table in the river started to decrease on 12 June and dropped to the normal summer level already on 15 June. Waterbirds arrived to inland parts of the island already after the ice-break on the rivers; the first Common Eiders and Buff-breasted Sandpipers were recorded on 2 June, Brent Geese, Pintails, Long-tailed Ducks and Grey Phalaropes on 6 June, King Eiders on 7 June.
In 2007 air temperatures did not drop below freezing during the whole summer until late September. This was a unique situation for the area. Not a single period of cold weather was recorded in the central part of the island during the breeding period. Dry and clear weather prevailed in June, with a particularly warm period from 19-23 June, when day-time air temperatures were above +20把, according to a subjective evaluation. During the whole month intermittant rain and drizzle occurred on 5 and 6 June, and were accompanied by fog associated with snow melting. Warm, dry, clear weather prevailed in the central part of the island also in July and August. Minimum night temperatures varied from +1.5-13.7把 in July, and from +5.7-10.3把 in the first half of August. Maximum day-time temperatures exceeded +20把 on 10 days in July and on 8 days in the first half of August, and only dropped below +10把 on a single days during this period (+7.6把 on 20 July). Precipitation occurred on 6 days in July and on 6 days in the period from 1-23 August, but was only heavy on 19 July and 18 August. The dry weather resulted in the drying of most bogs, many streams and decrease of the water level in lakes and rivers by July. The warm weather caused melting of the permafrost. This, in spite of the absence of notable precipitation, resulted in appearance of water in depressions and some streams from the second half of July.
Flowering of dryad was already over in the first week of July, and there was mass flowering of forbs in the second 10-day period of the month. Warm weather led to appearance of mosquitoes, which were generally uncommon on the island. They were observed from 4 July and were annoying on some nights during the second week of July. Butterflies were common until mid July, but almost disappeared by August. Yellowing of horsetail, sedges and grasses was recorded in some depressions on the first days of August, which were the first indications of phenological autumn. However, a repeated flowering of several species of early summer plants (Purple Saxifrage, locoweeds, Nakedstem Wallflower, louseworts, cinquefoils, etc.) occurred in the second week of August. Milk Mushrooms appeared in the dryad tundra in early August, while the growth in various other mushrooms, including champignons, was observed until mid September. Plants with berries are practically absent on the island.
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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: |
low
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Breeding conditions:
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Arctic Foxes were either seen, or heard daily. They apparently occurred in the area at a high density. They bred, and most of the dens were inhabited. Several Snowy Owls stayed in the station area during the whole summer, but the clutch of a single breeding pair was destroyed. One Peregrine Falcon was recorded. Pomarine Skuas were absent, while Long-tailed Skuas were common and bred successfully at a density of 1 pair/km2 (only one pair out of 5 in the station area failed to raise chicks). Wandering Glaucous Gulls were only regularly observed near waterbodies in the Tundra of Academy and they rarely visited the upland parts of the island.
Grey Plovers and Turnstones were the most numerous waders in the hillocky tundra of the study area; the former nested in the study plot at a density of 3.6 pairs/km2. Based on brood counts densities of Red Knots and Buff-breasted Sandpipers were the same at 0.85 pairs/km2, with local densities up to 2.5 and 2.1 pairs/km2, respectively). Dunlins and Pectoral Sandpipers were common waders in the Tundra of Academy.
We monitored 1 nest of Red Knots, 2 nests of Buff-breasted Sandpipers and 19 nests of Grey Plovers in the vicinity of the "Srednaya Neizvestnaya" field station. Chicks hatched in all nests of Red Knots and Buff-breasted Sandpipers, and in 12 nests of Grey Plovers (63%). Three nests of Dunlins were checked again 10 days later, yet prior to hatching, and all of them were still active. All eggs in 2 clutches of Grey Plovers (2 and 4 eggs) were unfertilized or contained dead embryos, and chicks did not hatch from another 4 eggs in 13 clutches (including 1 nest at the "Nizhnaya Tundrovaya" field station). Thus, the rate of embryonic failure estimated for a sample of 15 clutches with 58 eggs was unusually high in the Grey Plover (17.2%).
Four of 19 Grey Plover clutches (21%) were destroyed by avian predators and Arctic Foxes during incubation, and chicks in two nests were predated after hatching. Overall failure due to predation was 31.6%. Wader catching and ringing activities could have attracted predators and, thus, affected nest success; however, two of the predated nests were not visited by observers for a long time after finding and no catching was undertaken there. Predation pressure on clutches of waders and Long-tailed Skuas can be evaluated as low in 2007. Generally good reproductive performance by waders on the island was also indicated indirectly by the commonness of juvenile waders of all common species in late July - early August. Regular observations of broods of the Common Eider on rivers, broods of the King Eider and Long-tailed Duck on lakes in the Tundra of Academy, and high abundance everywhere of broods of the Snow Goose indicated successful reproduction of these birds also.
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Rodent dynamics:
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| The distribution of lemmings was uneven across the island, and their abundance was low. Lemmings were observed at several sites, but regular encounters were made only in the vicinity of the buildings of some field stations in the reserve. Lemmings were recorded several times in the area of the "Srednaya Neizvestnaya" field station, and their multiyear burrows in the river floodplain and on the slopes of hills were not cleaned out by animals in July. At this time inhabited burrows were found only on the Northern Plain (Tundra of Academy), but in August we begin to encounter them also in the foothills, which indicated some reproduction and dispersion of lemmings in summer.
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Rodent species recorded:
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Summary
of fauna studies: |
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