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RESPONDENT
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Sergey Paskhalny
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SITE NAME
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Lower Ob floodplain, western Siberia, Russia
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| Contact details
(phone/fax//e-mail//address): |
| (34992) 5-19-10 // spas2006@yandex.ru // Zelyonaya Gorka, 18-1, Labytnangi, Tumenskaya oblast, 629400, Russia
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PROJECT DETAILS |
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Project name:
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Lower Ob ornithologocal expedition
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Start of survey:
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End
of survey: |
Team
size: |
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1.04
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30.09
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1
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WEATHER
CONDITIONS
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| Season phenology: |
average
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Weather conditions: |
April was relatively warm and windless with air temperatures ranging from -20-22°C to +8°C; warming was recorded on 6-9, 15 and 17-25 April. Pelting rain had started on 17 April in the evening and continued until the morning of the next day. The next warming on 21-22 April was also accompanied by drizzling to pelting rains.
The period from 1-20 May was fairly cold, and air temperatures dropped to -20 C on 1 May. Snowfall occurred on 4 May, and then nearly incessant snowfalls of varying intensity were recorded from 7-13 May. The weather changed on 17 May when air temperature rose above the freezing point, and snowfall turned into heavy rain. Air temperatures reached +2-8°C on 17-19 and 21-22 May. Ice-break had started on 20 May on the main channel of the Ob River, and the latter cleared quickly because the ice was thin and loose. The flood was not high. The weather turned cool again later with short-term snowfalls on 20-23 May and more prolonged snowfalls on 29-30 May. There was a strong south-westerly gale on 28 May with wind speeds reaching 20-25 m/s.
The first half of June was cold and air temperatures generally did not exceed +5°C from 1-13 June. Air temperature dropped below the freezing point for the last time on 11 June, when it reached -2°C. Snowfalls occurred regularly on 1-3 and 5 June, with the last record on 11 June. Air temperatures increased to +15°C on 20 June, and daytime maximum temperatures reached +22-26°C later. The first thunderstorm was recoded on 23 June in the evening, and phenological summer had started. The weather was generally wet in June with precipitation occurring on one third of all days; rains of different intensity were observed on 4, 8-10, 15-18 and 23-24 June. The first half of the month was windy with prevailing northerly winds of 5-10 m/s (up to 12 m/s).
July was hot and dry. Air temperatures were above +15°C most of the time, on some days remaining above +20°C during the whole 24 hour period. Conditions were particularly hot on 1-7 and 16-18 July, with temperatures reaching +27-29°C. A single light rain was recorded before 18 July, then a thunderstorm occurred on the latter date, after which periodic light rains or short-term showers were recorded on 19-23 and 25 July.
August was warm but wetter than July. Prevailing temperatures ranged from +10°C to +16-18°C (on 1-5, 15-21 and 30-31 August), and +19-23°C were reached on the warmest days, 18 and 19 August. Minimum temperature (0°C) was recorded at night on 29/30 August. Rains occurred rarely and were mostly light and short-term; there were weak variable winds.
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| Date of 50%
snow-cover: |
20-25.05
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| Date of ice-break on
rivers: |
20.05
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| Date of final loss of
snow: |
30.05
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BIOTIC
CONDITIONS
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| Rodents abundance evaluation: |
average
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Breeding conditions:
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The Hooded Crow and Snow Bunting arrived on 1 and 5 April, Whooper Swan on 18, White-tailed Sea Eagle on 21, and Herring Gull on 25 April, Rough-legged Buzzard on 3 May, Fieldfare on 5, Chaffinch on 6, Short-eared Owl on 11, Shorelark on 13, geese and White Wagtail on 18, Northern Harrier and Lapwing on 19. A majority of species appeared after 20 May: Merlin on 21, Redstart on 22, Redwing on 24, Little Gull and Meadow Pipit on 26, Wood Sandpiper, Siberian Accentor, Willow Warbler, Bluethroat, Brambling and Little Bunting on 29. The intensity of migration was low, and it was not recorded on some days even at the end of May. However, early migrants appeared on the usual dates or approximately one week earlier, while late migrants arrived on the usual dates or later, in the second half of May or in June. This difference was, probably, explained by a relatively cold weather during the last 10 days of May and early June.
Birds of floodplain habitats depend heavily on the height and duration of the flood, and the latter was long in 2007. The second flood was caused by precipitation in the second half of July, and the water table remained at a high level until mid September. This resulted in the flooding of extensive floodplain areas, including patches with high willow trees and causeways. An associated shortage of nesting habitats for ground and shrub nesting birds caused changes in their distribution in the floodplain. Breeding density increased locally, but overall species diversity and density decreased. Nesting of the Ringed Plover, Little Ringed Plover, Terek Sandpiper and Temminck's Stint was recorded on dams. Wood Sandpipers, Greenshanks and Common Snipes were recorded locally on unsubmerged ridges, but their numbers decreased considerably.
The Hooded Crow, Herring Gull and Common Gull were the principal avian predators in the floodplain. Dogs regularly visited the area. No evidence of breeding of rodent specialists was recorded on watersheds.
The breeding success of waders was not high, judging by behaviour of birds and finding of nests. Four of 6 monitored clutches of Terek Sandpipers were lost; one clutch of 4 eggs produced 3 chicks, but the chicks apparently died, and a single pair managed to raise chicks to fledging. Nesting was successful in 2 of 3 pairs of Little Ringed Plovers and in 1 of 2 pairs of Ringed Plovers. One of 3 clutches of Temminck's Stints was probably lost.
Common Terns nesting on artificial dams near floodplain lakes were the most successful among other birds. With the exception of the Tufted Duck, numbers of ducks were extremely low, but some pairs managed to raise chicks. Abundant juvenile pipits, wagtails, warblers and buntings appeared in the floodplain in August, apparently having arrived from other habitats, because breeding opportunities for birds in the floodplain were very limited.
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Rodent dynamics:
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| Rodents were not recorded in the floodplain due to the high flood, with an exception of the Water Vole which was common in late May and early June. The abundance of rodents in watershed habitats near the Labytnangi town was also low.
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Rodent species recorded:
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| Latin | Abundance |
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| Arvicola terrestris | common |
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Summary
of fauna studies: |
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