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Based on the notion of age distribution stationarity in thanatocenoses, a reconstruction algorithm of the recruitment dynamics in Conchifera populations is advanced. The number of individuals that achieved an age of 1+ is taken as the recruitment size because in the populations of long-lived mollusks the formation of generations is completed not earlier than during the second year of life. The average long-term annual value of recruitment is proposed to be considered as an index of the background state of such populations.
Magomedov M. Sh.
Quantitative and qualitative characteristics of the feeding of rodent species coexisting in woodland associations in the foothill zone of the Republic of Daghestan were studied. The food species composition, the shares of food items and the index of diet similarity in the model rodent community were revealed per season. Various rodent species consumed different plant species. The diet of Sylvaemus fulvipectus, Apodemus agrarius, Cricetulus migratorius, Microtus socialis and Dryomys nitedula consisted of 22, 18, 19, 21 and 17 plant species, respectively. The number and percentage of exclusively consumed plant species, the total share of which in the diet did not exceed 30%, were estimated. The index of interspecies diet similarity varied within a wide range. This index in different rodent species was shown to correlate with the structure of herbaceous vegetation in the environment. Thus, a growth in overground phytomass and in the share of grasses in a plant community determined a significant increase in diet similarities.
Monakhov V.G., Kolobova O.S.
We provide an overview of the main results of a 4-year long study of the present distribution of furbearer mus-telid species in the Middle Urals, Sverdlovsk Region. We applied a new non-invasive genetic method based by PCR analysis of DNA extracted from animal excrements. Altogether, 151 samples were involved in the analysis, species identities established for 135 samples. Among the latter, 80% belonged to the American mink, 14.1% to the otter, 2.2% to the pine marten, and 3.7% to the sable, while the European mink seems to be absent from the study area. A species dominating the near-floodplain habitats in the Middle Urals is the American mink, followed by the otter.
Prokina K.I., Mylnikova A.P., Galanina O.V., Philippov D.A.
The species composition and morphology of heterotrophic flagellates collected from bog hollows, bog pools, bog streams and watercourses were studied in the Pinega District, Arkhangelsk Oblast', NW Russia. 50 species of flagellates belonging to 4 macrotaxonomic clusters were recorded. Most of the flagellates were bacte-rivorous, 2 species were predators and further 2 species were omnivorous. The mire type in general and mire waterbodies in particular supported their own set of species (ANOVA: F = 15.5, p < 0.001). Thus, 34 species of heterotrophic flagellates were revealed in eutrophic mires (space between hummocks and streams), 26 in oligotrophic mires (hollows, bog streams, bog pools). The protist fauna was extremely poor in bog pools (2 species). Non-parametric MDS-analysis revealed 4 groups of communities: 1) hollows and laggs; 2) space between hummocks, hollow and stream; 3) degrading hollows-rimpi; 4) small lake. The species richness depended on electric conductivity (т = 0.65, p = 0.002). Descriptions, drawings and pictures of the most poorly-known species are presented, taking into account particular structures of the cell. All species discovered are new to the fauna of Arkhangelsk Oblast'
Gimranov D.O., Kosintsev P.A.
The structure of both upper and lower incisors is studied in the brown ( Ursus arctos) and polar ( Ursus mariti-mus) bears, and incisor morphotypes are delimited. A description and the frequency of occurrence of each morphotype are given. The brown bear is revealed to show a greater degree of morphotypic variability of the incisors, both upper and lower. This species is characterized by a more complex structure of the corona compared to the polar bear. A west-east trend in increasing tooth complexity is observed in U. arctos populations. Based on incisor structure, mainland brown bears somewhat differ from those from Hokkaido. Within that island, differences are noted between the western, central and eastern populations. The incisors of the polar bear are generally better adapted to carnivory than those of the brown bear. The main evolutionary trend in the development of incisors in Ursus representatives is grinding surface simplification.
Results of the studies and publications of the last decades on the origin of active flight in bats and birds are rigorously analyzed (Norberg, 1985; Ковтун, Леденев, 1999; Long et al., 2003; Курочкин, Богданович, 2008; Панютина и др., 2012; Ковалева, 2013; Богданович, 2014; and others) with expressed different views on the origin of bats and the emergence of powered flight in birds and bats. The main question discussed is whether or not gliding in bats had occurred prior to active flight. According to comparative morphological, embryological and cytological studies, the key morpho-functional alterations of the walking thoracic limbs of bat ancestors during the emergence and development of flapping flight are shown to have occurred in au-topodia. The most significant of autopodial reorganizations seem to have been the elongation of the second to fifth metacarpals (Mc 2-5), this having served as a root cause for the formation of an embryonic interdig-ital membrane. The first finger was not involved in the evolutionary transformations of the wrist and thus was capable of providing locomotion (climbing tree trunks) at transitional stages in the evolution of walking limbs into the wing. The defended hypothesis is that gliding is a dead-end direction in terms of the development of active flight.
Rubtsov A.S., Tarasov V.V.
We studied the phenotypic composition of populations and the variability of the song in two Bunting species in three localities at the western border of the sympatry zone: in the south of the Tyumen region and in the centre and south of the Kurgan Region. Over the last several decades, the zone of contact of the studied species has expanded significantly. The Pine Bunting started breeding regularly in the area in the end of the 20th century and at present it is considered as a common species comparable in abundance to the Yellowhammer. The share of phenotypic hybrids varies from 25% to 50% reaching its maximum at the boundary of the Pine Bunting nesting range. East of this boundary the hybridization level is reduced, this being seen in a sharp decrease in the share of "leucocephala hybrids". An aalysis of the phenotypic variability of the hybrids shows that they may be divided into two groups similar in coloration to the parent species. The study results let us presume that the hybridization is limited and hybrids return mostly to backcrossing with the parent species. This presumption also finds its support in an analysis of song structure: there the Yellowhammer and the Pine Bunting have songs of different, easily distinguishable dialects.
Andreychev A.V., Lapshin A.S., Kuznetcov V.A.
A new technique of eagle owl registration is offered based on acoustic signals recorded with the use of a portable digital voice recorder. The recorder allows recording the vocal activity of a large owl at a distance of 4 km from the place of installation to the screaming bird, depending on wind direction and speed, as well as on terrain relief. The continuous operation time of a recorder using one set of external alkaline batteries lasts about 140 hours. The method was tested in the conditions of the forested steppe zone in the Volga region. Applying this technique, at a preliminary stage 7 new nests and 17 additional nesting sites were revealed during one year alone. The older techniques of direction-finding and combing the area used earlier (2008-2014) spotted only 6 nests. The benefits of the new technique proposed lie in covering larger areas and saving time.
Rozenfeld S.B., Sheremetev I.S., Baranyuk V.V.
The Lesser Snow Goose (Anser caerulescens caerulescens) is one of the most abundant geese globally. Its nesting distribution area which mostly lies in North America is presently expanding, with the numbers over the last 50 years grown from 1 to 15 million. Yet this goose species which has been exterminated in Eurasia fails to recover its historical range. The only large breeding colony in Eurasia has persisted on Wrangel Island, where the birds share food resources with ruminants. To find out what prevents the geese from dispersal and the establishment of new colonies on the island, we estimated the trophic niche overlap and competitive advantages in habitat choice. We show that ruminants are stronger trophic competitors to geese, while in most of the habitat types associated with the goose colony the level of trophic competition and/or resource shortage is higher than in post-colonial ones, where the resources are more diverse and abundant. We conclude that, in the present conditions of goose numbers growth on Wrangel Island, neither the restoration of extinct nor the initiation of new colonies is hampered by resource shortage and/or the stronger competitors (ruminants). The factors related to the distribution of food resources and to competition fail to determine the choice of a nesting site. This probably concerns arctic Eurasia in general.
Afanasiev R.G., Vinogradov V.V., Lineicev S.N.
In the 20th century, both the distribution area and numbers of the Siberian ibex decreased considerabtly in the near-Yenisei part of the West Sayan, Siberia After filling the Sayano-Shushensky Reservoir with water, the distribution area became disrupted into three territorial groups: the Usinsk, the Urbansky and the protected left-bank. Currently the area totals 89000 hectares, and the numbers 3000 animals. The population density is higher in the steppe areas of mountain slopes not accessible to the wolf of the rock, coupled with available closed shelters, forest or high shrubs, and relatively safe drinking places. The sex and age composition is usual for the species: males ~30-35%, females ~45-50%, young ~20%. The largest flocks are formed during spring and amount to 500-600 individuals. In summer, most of the males and females stay separated. The herds consisting of females and their young are composed of up to 80 individuals. In October to early November, mating games start while the animals form mixed herds numbering 7-15 individuals. The most conservative both in composition and size are the herds of females with the young joined for a short time by males of different age groups. In general, the Siberian ibex population in the near-Yenisei part of the West Sayan is presently in a stable condition, the human impact being minimal.
С позиций теории жизненных циклов проанализированы размеры тела, продолжительность жизни, скорость роста и интенсивность размножения особей периферической популяции полчка Жигулевской возвышенности. Характерная особенность размножения вида на всем протяжении ареала - периодически повторяющиеся годы полного отсутствия потомства. В репродуктивно успешные годы наблюдается опережающее размножение: рождение детенышей предшествует периоду максимального обилия пищи. В оптимуме ареала, в Центральной и Западной Европе, в неблагоприятные годы механизм регуляции размножения основан на подавлении репродуктивной активности самцов в начале активного сезона. В жигулевской популяции регуляция рождаемости осуществляется на основе массовой резорбции - рассасывания всех эмбрионов у подавляющего большинства самок грызунов. В этой популяции размеры и масса тела животных минимальны: разница по массе тела при сравнении с особями из других популяций может достигать трех раз. Особенности биологии полчка в периферической популяции связаны с параметрами жизненного цикла. В отличие от центральноевропейских популяций, здесь размножение вида отмечается ежегодно. Однако у беременных самок в годы недостаточного урожая основных кормов происходит гибель эмбрионов. У самцов в этой популяции, ежегодно участвующих в спаривании, не выявлено репродуктивных плат, связанных с потерями массы тела. Более низкая скорость роста по сравнению с таковой в популяциях, обитающих в оптимуме ареала, проявляется в том, что по морфометрическим параметрам можно условно выделить четыре возрастные группы. У годовалых самцов, рост которых не закончился, начало периода спариваний зависит от массы тела. Продолжительность жизни в данной популяции обычно не превышает четырех лет, что значительно ниже, чем в других исследованных популяциях, в которых она составляет 7-9 лет.
ЗУДОВА Г.А., ПРОСКУРНЯК Л.П., НАЗАРОВА Г.Г.
Разработан метод определения возраста и пола водяной полевки (Arvicola amphibius L.) по промерам костей тазовой конечности. Материал получен на животных виварного разведения известного возраста. С применением дискриминантного анализа найдены классификационные функции для разделения животных анализируемой выборки (n = 56) на возрастные классы с точностью до года, а также для идентификации пола. Проверка на контрольной группе (n = 34) показала, что возраст 90.0% самцов и 92.9% самок определен правильно. Корректность классификации по полу составляет 100%.