The main natural changes related to the climate variations and the economic activities over the past 250 years in the area of the clay semi-desert along the interfluve between the Volga River and the Ural River have been considered. The authors define four climate periods based on humidity in the region: the mid-18th century to the 1820s, the 1830s to the 1950s, the 1960s to the end of the 1980s, and the 1990s to the 2010s. For each period, the area features related to humidity and human economic activities, which are followed by altering life for plants and animals in the region, are described. It is proven that only the existence and patterns of aquatic and waterfront communities are directly dependent on the climatogenic factors. Most changes in wildlife of the other communities reflect the impact of regional economic activities representing different stages and types, while the climate variations only adjust them. The ravine forests that existed in lake depressions until the 19th century could ensure the presence of a ravine-woodland complex in the regional fauna. After clearing these forests, a part of the ravine-woodland species complex completely disappeared from the region, some part became synanthropes, while others, once extinct from the region, then recolonized with the occurrence of polydominant woody-shrub thickets in lake depressions and afforested plains. A shift from a steppe vegetation formation to a desert formation across the plain occurred because of overgrazing during the dry season. Therefore, some steppe animal species also became extinct in the region, while the desert animals occupied the niches left vacant. Plowing of the flatlands caused the occurrence of wildlife species using the arable fields in the region as feeding habitats. Anthropogenic activities of various kinds contributed to the arrival of the range-shifting species.

The results of long-term monitoring of the long-legged buzzard, which nests in artificial tree–shrub communities of the clay semidesert of the Trans-Volga region, are presented. Observations, which started in the 1980s and were carried out in the Pallas district of the Volgograd oblast (Russia) and in the West Kazakhstan oblast (Republic of Kazakhstan), show that the lack of natural objects suitable for nest building made this bird dependent on human activity. The forest belts created in the 1950s–1970s dramatically expanded the potential nesting area of the long-legged buzzard and brought it out of local habitats like lake basins and spiraea gullies into the zonal plain. Here, around transportation routes and in the environs of settlements in the areas especially strongly developed by man, first a stable and then an oversized population of this bird was formed by the beginning of the 21st century. Since the 2010s there has been a decrease in the numbers of nesting birds, the reason for which being a drop in the numbers of ground-squirrels and the development of a tall-grass cover, thus making it difficult for birds to find prey. The degradation of artificial plantations deprived of care still renders little effect on the numbers of nesting pairs. Birds stubbornly maintain the preferred distance between the nests of 1.5–2 km. A decrease in this distance is noted sporadically, indicating both a shortage of nesting places and a high food capacity of the territory.

The results of a 30-year long monitoring of the long-legged buzzard nesting in natural tree-shrub communities in a clay semi-desert of the Trans-Volga region are presented. In such communities, buzzards are shown to nest exclusively in crab-trees or 3-4-meter high common buckthorn growing in polydominant shrublands both in lake depressions and in large depressions on the plain. Since these plant species in plain depressions are subject to strong anthropogenic impact and fail to reach the required height, only polydominant shrubs are suitable for long-legged buzzard nesting and form sufficiently dense thickets in nesting areas. A tiny area of such communities cannot ensure the conservation of the species within the region. The maintenance of the buzzard and other bird species is currently due to the presence of artificial woods. Biodiversity in the Volga-Ural interfluve clay semi-desert primarily depends on the preservation of existing artificial woodlands, as well as on the conservation and restoration of endangered natural tree-shrub ecosystems.

RUSSIAN JOURNAL OF FOREST SCIENCE. 2017, No. 3, pp. 221-227 NESTLING BIRDS OF RAVINE FORESTS INHABIT FOREST BELTS IN CLAY SEMI-DESERT IN TRANSVOLGA REGION A. V. Bykov, O. A. Bukhareva Institute of Forest Science, Russian Academy of Sciences Sovetskaya st. 21, Uspenskoe, Odintsovsky District, Moscow Oblast, 143030, Russia E-mail: buola@yandex.ru Received 27 May 2016 There were the natural shrublands and woodlands growing in ravines and depressions of salt lakes and rivers in clay semi-desert in Volga and Ural River interfluve in early 19 th century. They formed the faunistic character of the region with impoverished vertebrate complex typical for ravine forests and steppe and semi- desert species nestling in the trees. Thanks to human impacts these shrubs and woods communities including the fauna had nearly extinct by the onset 20 th century. The network of shrubs and woods had been planted in 1950s and the faunistic complex had started to recover. By early 21 st century dendrophilous birds are only outnumbered in species richness to those of wetland complex, and triple the species number of steppe birds. However currently the 50–60 year old plantations degrade, and the destiny of forest and dendrophilous nestling birds is a challenge. Keywords: clay semi-desert in Transvolga, birds of ravine forests, plantations. REFERENCES Bol'shakov A.F., Erpert S.D., Sheinin L.B., Puti sel'skokhozyaistvennogo osvoeniya polupustyni (Ways of agricultural devlopment of semi-desert), Moscow: Nauka, 1983, 73 p. Bykov A.V., Znachenie drevesno-kustarnikovoi rastitel'nosti dlya pozvonochnykh zhivotnykh glinistoi polupustyni Zavolzh'ya (The significance of arboreal vegetation for vertebrates of the clayey semi-desert of Trans-Volga region), Aridnye ekosistemy , 2010, Vol. 16, No. 45, pp. 90-97. Bykov A.V., Bukhareva O.A., The current state of ravine type shrub vegetation in the area of lake Elton, Arid Ecosystems , 2016, Vol. 6, No. 1, pp. 58-62. Bykov A.V., Bukhareva O.A., Izmeneniya v naselenii lesnykh i dendrofil'nykh ptits glinistoi polupustyni Volgo-Ural'skogo mezhdurech'ya za 60 let (Changes in the population of forest and dendrophilous birds of the clay semi-desert of the Volga-Ural interfluve for 60 years), Povolzhskii ekologicheskii zhurnal , 2015, No. 2, pp. 148-158. Bykov A.V., Olovyannikova I.N., Sapanov M.K., Rol' zoogennykh faktorov pri sozdanii kolochno-zapadinnogo landshafta v glinistoi polupustyne Zavolzh'ya (Role of zoogenic factors in creating kolok-rading landscape in clay semideserts of Zavolzhye), Lesovedenie , 1993, No. 6, pp. 27-33. Chernetsov N.S., Bulyuk V.N., Ktitorov P.S., Rol' Dzhanybekskogo oazisa kak mesta migratsionnykh ostanovok dendrofil'nykh vidov vorob'inykh ptits (Role of Dzhanybek oasis as a migratory stopover site for forest passerines), Povolzhskii ekologicheskii zhurnal , 2010, No. 2, pp. 204-216. Dinesman L.G., Izmenenie prirody severo-zapada Prikaspiiskoi nizmennosti (Environmental change in northwestern Caspian Depression), Moscow: Izd-vo AN SSSR,, 1960, 160 p. Doskach A.G., Prirodnoe raionirovanie Prikaspiiskoi polupustyni (Natural zoning of Caspian semi-desert), Moscow: Nauka, 1979, 142 p. Lindeman G.V., Kurgannik ( Buteo rufinus Cretzschm.) v mezhdurech'e Volgi i Urala (The long-legged buzzard ( Buteo rufinus Cretzschm.) at Volga - Ural watershed), Byulleten' Moskovskogo obshchestva ispytatelei prirody. Otdel biologicheskii , 1985, Vol. 90, No. 6, pp. 27-37. Lindeman G.V., Bykov A.V., Letnie skopleniya negnezdyashchikhsya orlanov-belokhvostov Haliaeetus albicilla (L.) v zavolzhskoi glinistoi polupustyne (Summer gatherings of non-breeding ernes Haliaeetus albicilla (L.) in the clay semidesert of the left bank of the Volga-River), Byulleten' Moskovskogo obshchestva ispytatelei prirody. Otdel biologicheskii , 2010, Vol. 115, No. 5, pp. 28-32. Magomedov M.-R.D., Dinamika naseleniya pozvonochnykh zhivotnykh Zavolzhskoi polupustyni (Moscow: Nauka, 2005, 250 p. Naglov V., Zagorodnyuk I., Statisticheskii analiz priurochennosti vidov i struktury soobshchestv (Statistic analysis of spatial patterns of species and communitites), In: Teriofauna shodu Ukrai'ny (Mammal fauna of Eastern Ukraine) : 2006, Vol. 7, pp. 291-300. Pesenko Y.A., Printsipy i metody kolichestvennogo analiza v faunisticheskikh issledovaniyakh (Principles and methods of quantitative analysis in studies of fauna), Moscow: Nauka, 1982, 287 p. Rode A.A., Pol'skii M.N., Pochvy Dzhanybekskogo statsionara, ikh morfologicheskoe stroenie, mekhanicheskii i khimicheskii sostav (Soils of Dzhnybek station: morphology, structure, grain size and chemical composition), In: Pochvy polupustyni Severo-Zapadnogo Prikaspiya i ikh melioratsiya. Po rabotam Dzhanybekskogo statsionara (Melioration of soils of semi-desert in northwestern Caspian region: studies from Dzhanybek station) Moscow: Izd-vo AN SSSR, 1961, pp. 3-214 (295 p.).

The modern situation of the vertebrate population in the clay semidesert of the interfluve of the Volga and Ural rivers differs significantly from that observed 50–60 years ago. This is due to the fact that reduction of ravine forests and steppe shrubs (which began in the 18th century) has extremely affected the forest and dendrophilous animals. The artificial afforestation, especially intense since the middle of the 20th century, provided surrogate “forest” sites in the region by the end of the 1970s. This helped to restore the missing species and raise the abundance and dispersal of forest and dendrophilous animals. By the beginning of the 21st century, afforestation had stopped in the region and the plantation areas had begun to shrink. Some trends in the populations of mammals and birds can be already noticed.

By the end of the XX century, the ravine forests of the Volga–Ural interfluve degraded as a result of anthropogenic impact and turned into polydominant shrubberies, the area of which continues to decrease. In 2013–2014 the current state of such plant communities was studied on the northwestern coast of Lake Elton. The total area of shrubberies has already decreased by 50% because of fires, and their fire resistance declines constantly as a result of grazing.

The current state and resilience to wildfire disturbances of the natural tamarisk ( Tamarix laxa Willd) communities at on the coasts of Lake Buluchta, a salt lake, Caspian Depression (the Volga and Ural Rivers interfluve) is considered. The unique ecosystems of the natural Tamarisk communities are able to persist in specific biotopes of natural water basins only.

There are preserved areas that have been minimally disturbed by erosion processes on the eastern shore of Lake Buluhta. It was shown on two profiles, which start from the bottom of the lake and extend up to the second lake terrace, that not dissected shoreline leads to poor reedbeds and not swamping of shore-land. This restricts the ability for nesting of many species. At the same time, not dissected coastline ensures the preservation of relict tamarisk thickets, which are characterized by a habitat of rare forest species of mammals and leads to migration birds flocking.

The structure and metric parameters of social vole burrowing systems of different ages are considered. The data on temperature in holes and on the soil surface during growing season are presented.

A NEW METHODOLOGY INVENTORYING INVERTEBRATES IN GALLERIES OF SMALL MAMMALS O. A. Bukhareva Institute of Forest Science, Russian Academy of Sciences, Uspenskoe, Moscow region 143030, Russia e-mail: buola@yandex.ru Anew methodology inventorying moving invertebrates in the burrows of small mammals is proposed. The data obtained are expressed in the number of individuals per a trap-day that enables to compare them with the results obtained in the registration of invertebrates by Barber soil traps.

A novel method for surveying motile invertebrates in the burrows of small mammals is proposed. The data obtained are expressed as the number of individuals per trap-day and are therefore comparable with the results obtained using Barber traps.

The social vole (Microtus socialis Pall.) is a landscape species of the Trans-Volga clayey semidesert, which disappeared from the zonal plain in the 1970s but survived in various habitats of lake depressions. In 2009, it settled over the blind plain again. The reasons for the departure and then return of the vole are not known. This phenomenon might be one of the cyclic changes in the specific composition and abundance, which are characteristic of many animals of this region.