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RESPONDENT
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Vasily Sokolov
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SITE NAME
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Erkatayakha and Payutayakha rivers, Yamal, Russia
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| Contact
details (phone/fax//e-mail//address): |
| (343) 210-3858, add. 104/89028432787 // vsokolov@inbox.ru // Lab. of biocenological processes, Inst. of plant and animal ecology, 8 Marta Str, 202, Ekaterinburg, 620144 Russia |
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PROJECT DETAILS
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Project name:
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Dynamics of bird numbers on south-western Yamal |
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Start of survey:
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End
of survey:
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Team
size:
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8.06 |
27.07 |
6 |
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WEATHER CONDITIONS
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| Season
phenology: |
average |
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Weather conditions: |
| According to reports of local people spring development was very rapid which resulted in early nesting of some bird species belonging to early migrants (geese, swans, some passerines). However, adverse weather conditions (frequent snowfalls, rains, northern wind and relative low temperature) prevailed during arrival of most species, thus arrival and start of nesting of most passerines and waders were prolonged. Pelting rain was replaced by abundant snow in the period from 16 to 18 June, and water table in rivers and connecting lakes reached flood-time level. Presumably, high water was responsible for flooding of duck and wader nests, as hatching in all found nests of ducks started only after 25 July. Weather was favourable for bird breeding in the second half of June to mid July. Air temperature was especially high from mid June to mid July and reached +36øC on some days. Second broods were found in some species of passerines. |
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| Date of 50%
snow-cover: |
25-30.05 |
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| Date of ice-break
on rivers: |
27.05-10.06 |
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| Date of final loss
of snow: |
15-18.06 |
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BIOTIC CONDITIONS
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| Rodents abundance evaluation: |
average |
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Breeding conditions:
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According to reports of local people Willow Grouse were more abundant in winter compared with previous years, and hares also occurred in high numbers. Arctic Foxes were numerous until November, but then they migrated elsewhere. Numbers of Snowy Owls in winter were not high and reached previously observed levels only in October.
Predation was low in summer as solitary Arctic Foxes were recorded, numbers of skuas were low, Rough-legged Buzzards were seen only in June and their nests failed due to low numbers of rodents. We observed falling of nests of birds of prey on bluffs after the period of inclement weather from 16-18 June.
Reproductive success was very high in passerines and ptarmigans due to favourable conditions during egg-laying, incubation and brood-raring. Nests of waterfowl and divers near shoreline of rivers and lakes presumably were flooded in mid June judging by high numbers of non-breeding geese in late June and late hatching in ducks. |
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Rodent dynamics:
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Local people explain low numbers of predators in winter by frequent rains in October-November 2002 which caused freezing of thin snow into ice layer. Then snow was removed from this layer surface by winds, and bushes were not covered by snow during the whole winter. Presumably, winter weather conditions adversely affected lemmings and Microtus voles and did not allow them to reach peak numbers which should have occurred according to our prognosis. Local herdsmen reported findings of dead rodents during winter, and also characterized winter as very unfavourable for reindeer.
We captured 5, 25 and 3 Collared Lemmings, Middendorff's Voles and Narrow-skulled Voles, respectively, using snap-traps. Numbers of Middendorff's Voles and, probably, Collared Lemmings have increased by the end of July, and pregnant females were found in the latter species.
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Rodent species recorded:
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| Latin | Abundance |
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| Dicrostonyx torquatus | rare |
| Microtus middendorffi | common |
| Microtus gregalis | rare |
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Summary
of fauna studies: |
| Absolute bird counts were conducted on plots of different size depending on species: 3.5 sq.km for waders and some passerines, 10 sq.km for ducks, ptarmigans and some waders and 100 sq.km for geese, swans and birds of prey. |
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