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RESPONDENT
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Vasili Baranyuk
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SITE NAME
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Tundrovaya River valley, Wrangel Island, Russia
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| Contact details
(phone/fax//e-mail//address): |
| (095)441-12-16 // vvbar@vvbar.msk.ru // Lomonosovsky Pr., 35-40, Moscow, Russia
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PROJECT DETAILS |
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Project name:
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Monitoring and population ecology of Snowy Geese on Wrangel Island
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Start of survey:
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End
of survey: |
Team
size: |
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27.05
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18.08
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1
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WEATHER
CONDITIONS
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| Season phenology: |
average
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Weather conditions: |
| A small amount of snow was accumulated during the winter 2003-2004 (41 mm of winter time precipitaion vs. 79 mm on average for 1927-2004). However, snowstorms in May resulted in preservation of snow cover on more than 90% of surface by the end of the month across most of the island and also in the Snow Geese colony area in the middle reaches of the Tundrovaya River. Snow layer was only 10-15 cm thick on flat surfaces, while southern slopes of the mountains were already free from snow in late May. May was relative warm, and mean monthly air temperature -4.2øC was above long-term average -6.8øC for 1927-2004. Air temperature rised above freezing at day time on 29.05 and continued to increase rapidly from this date. Temperatures rised above +10øC on 2.06 resluting in intensive snow melt. Snow cover dropped to 50% by 6 June, and completely melted on flat surface by 10 June. Water table was increasing in creeks from 2-4.06, and ice broke on the Tundrovaya River on 4.06. Clear sunny weather prevailed until 18.06, with maximal temperatures reaching +25øC on some days, which resulted in drying of tundra, disappearance of many snowbanks and creeks. Cool weather with alternating nebulosity, fogs and rare rains prevailed from 19-26.06, and was followed by war period lasting until 4.07. July was mostly cold with frequent fog and rain. A single warm period of sunny weather with air temperatures above +20øC on 10-11.07 ended in the evening on 11.07, when speed of unusually strong for summer western wind was reaching 30 m/s. Air temperatures dropped below freezing at night, while rain on 14.07 turned into wet snow which blanketed the ground and melted on the next day. Generally, the season was average in timing, with generally warm and dry June and cold and wet July. August was and dry compared with July. Mean monthly air temperatures were 2.9øC above long-term average in June, 0.4øC below average in July, and 3.0øC above average in August.
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| Date of 50%
snow-cover: |
6.06
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| Date of ice-break on
rivers: |
4.06
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| Date of final loss of
snow: |
10.06
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BIOTIC
CONDITIONS
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| Rodents abundance evaluation: |
low
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Breeding conditions:
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Wrangel Island population of Snow Geese is currently estimated from 115-120 thousand birds. Breeding of geese on the main colony in the Tundrovaya River valley occurred 2-3 days earlier than average in 2004. Mass arrival of geese in the area happened on 29-30.05, but first nests were found already on 28.05. While much of the area was still snowcovered at this time, geese were lacking sufficient territory for nesting. Thin snow melted first in willow bushes, and these habitats attracted geese, resulting in increased competition for nesting territories, increased breeding density (up to 240 nests/hectare), abandonment of nests due to hostile social environment, nest parasitism and laying of eggs on bare ground in clamps of up to 28 eggs. Rapid snow melt in June allowed geese to establish colony of 28.4 thousand nests. Mean clutch size was 3.60ñ0.05 (n=645), and was signiuficantly higher in area of intense competition for nesting territories. Hatching started on 24.06, which is earlier than average for the period 1970-2004 is 27.06, and first broods started to leave the colony on 25.06, moving to the northern plane of the Tundra of Academy. The main flow of broods was moving along the Tundrovaya River, because elsewhere tundra was dry due to dry season conditions. Mean brood size was 3.16ñ0.08 (n=455) for the broods which left the colony. Hatching occurred in about 75% of nest on the main colony, which means that approximately 7 thousand of nests perished primarily due to numerous predators. Approximately 67 thousand chicks left the main colony area. Unfavourable weather conditions in the brood-raring period, in particular in the first two weeks of July, and abundant predators in the Tundra fo Academia should have adversely affected number of goslings surviving to fledging. Generally reporductive performance of Snow Geese was slightly below average in 2004. Proportion of juveniles on the wintering grounds was reduced to about 12%, while normally it should have been about 20% for a relative large colony size in 2004.
Numbers of Arctic Foxes were high in the colony vicinity, they were in good condition, and many of them bred despite low lemming numbers. This resulted from rapid warming with rain and glaze on tundra followed by mass perishing of reindeers in late October - early November, after which 50 corpses were left only in the colony area of about 100 sq.km. Abundant food provided for survival and good physical condition of Arctic Foxes during the snow period, however low lemming numbers adversely affected survival of the young. Many cubs were in poor condition already in July and perished from deseases. However, lemming numbers were considerably higher and reached the rank of average in some parts of the Tundra of Academia, where Arctic Foxes and Snowy Owls bred, and fledglings of Pomorine Skuas were recorded. Snowy Owls and Pomarine Skuas were rare and did not breed in the colony vicinity.
Apart of tradition predation by Arctic Foxes and Glaucous Gulls, nests were also destroyed in 2004 by Wolverine and Red Fox. Number of Wolverines has increased on the island during the last years, and they became regular visitors of the gees colony. A visit of a pair of Walverines was documented in 2004. Red Fox was observed eating eggs on the colony in the beginning of incubation. Red Fox and Wolverine are larger predators compared with Arctic Fox, and unlike the latter they cannot be moved away from nest by a pair of geese protecting their clutch. Similarly, while geese can stop or change direction of moving flock of reindeers, they are not able to impact approaching muskox, whether a single animal or flock. Habitats used by geese for breeding also attracted muskoxen, which normally appeared there already after hatching. However, 2 males came to the colony before hatching in 2004 and stayed in area with high density of nests. Muskoxen apparently did not care about eggs and could trample them, but the harm from disturbance was by far greater. Geese were flashed from nests on approach of muskoxen at a distance of 3-4 m, and unattended eggs were destroyed by Glaucous Gulls which did not fear muskoxen. Approximately 600 geese nests were destroyed by up to 50 Glaucous Gulls associated with 2 muskox males in 2004.
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Rodent dynamics:
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Rodent species recorded:
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Summary
of fauna studies: |
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