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Russian Entomol. J. 21(2): 169178 © RUSSIAN ENTOMOLOGICAL JOURNAL, 2012 How many forest and steppe ground and darkling beetles (Coleoptera: Carabidae, Tenebrionidae) are there in West Siberian faunal assemblages? Ñêîëüêî ëåñíûõ è ñòåïíûõ æóæåëèö è ÷åðíîòåëîê (Coleoptera: Carabidae, Tenebrionidae) â ñîîáùåñòâàõ çàïàäíî-ñèáèðñêîé ëåñîñòåïè? V.G. Mordkovich Â.Ã. Ìîðäêîâè÷ Institute of Systematics and Ecology of Animals, Siberian Branch of the Russian Academy of Sciences, Frunze 11, Novosibirsk, 630091, Russia. Èíñòèòóò ñèñòåìàòèêè è ýêîëîãèè æèâîòíûõ ÑÎ ÐÀÍ, óë. Ôðóíçå 11, Íîâîñèáèðñê 630091, Ðîññèÿ. KEY WORDS: forest-steppe zone, taiga, steppe, tree stand, grass stand, West Siberian Plain, beetles, ecological spectrum, community, species richness, abundance. ÊËÞ×ÅÂÛÅ ÑËÎÂÀ: ëåñîñòåïü, òàéãà, ñòåïü, äðåâîñòîé, òðàâîñòîé, Çàïàäíî-Ñèáèðñêàÿ ðàâíèíà, æóêè, ýêîëîãè÷åñêèé ñïåêòð, ñîîáùåñòâî, âèäîâîå áîãàòñòâî, ÷èñëåííîñòü. ABSTRACT: Zoodiversity of the forest-steppe zone ÐÅÇÞÌÅ: Çîîðàçíîîáðàçèå ëåñîñòåïíîé çîíû is commonly believed to be resultant of the forest and îáû÷íî ñ÷èòàåòñÿ ñìåñüþ ëåñíîé è ñòåïíîé áèîò. steppe faunas mixture. According to this notion, the Ñîãëàñíî ýòîé âåðñèè îæèäàåòñÿ, â ñâåòå ãðÿäóùå- further climate warming is expected to shift the bal- ãî ïîòåïëåíèÿ, ñìåùåíèå áàëàíñà ëåñíûõ è ñòåï- ance between the forest and steppe biotic components íûõ ýëåìåíòîâ áèîòû â ïîëüçó áîëåå àðèäíûõ. Ïî towards more aridophilous ones. Many years of terres- èòîãàì ìíîãîëåòíèõ èññëåäîâàíèé íàïî÷âåííûõ trial beetles investigation revealed that their forest- æóêîâ âûÿñíèëîñü, ÷òî ñðåäè îáèòàòåëåé ëåñîñòå- steppe assemblages are dominated by species with po- ïè ïðåîáëàäàþò âèäû ñ ïîëèçîíàëüíûìè àðåàëàìè, lyzonal areas, but having maximal density populations íî èìåþùèå ïîïóëÿöèè ñ ìàêñèìàëüíîé ïëîòíîñ- in the forest-steppe zone. Proportion of species with òüþ â çîíå ëåñîñòåïè. Äîëÿ âèäîâ ñ ïðåèìóùåñòâåí- mostly forest and steppe metapopulations does not ex- íî ëåñíûìè è ñòåïíûìè ìåòàïîïóëÿöèÿìè íå ïðå- ceed summarily 30%. The forest-steppe terrestrial bee- âûøàåò â ëåñîñòåïè, ñóììàðíî, 30%. Ëåñîñòåïíûå tle assemblages displayed specific ecological group ñîîáùåñòâà íàïî÷âåííûõ æóêîâ îòëè÷àþòñÿ ñïå- structure dominated by species preferring meadow hab- öèôè÷åñêîé ñòðóêòóðîé äîìèíèðîâàíèÿ â ñïåêòðå itats. Analysis of beetle faunal assemblages similarity ýêîãðóïï âèäîâ, ïðåäïî÷èòàþùèõ êîëè÷åñòâåííî in respect to ecological group dominance structure re- ëóãîâûå ìåñòîîáèòàíèÿ. Àíàëèç ñòåïåíè ðàçëè÷èÿ vealed four series of phylogenesis in the forest-steppe. ñîîáùåñòâ ïî ñòðóêòóðå äîìèíèðîâàíèÿ ýêîãðóïï Each series begins from the transformation of different âûÿâèë íàëè÷èå ÷åòûðåõ ñåðèé ôèëîãåíåçà â ëåñî- archetype coenoses, apparently inherited from the peri- ñòåïè. Êàæäàÿ èç íèõ íà÷èíàåòñÿ ñ ïðåîáðàçîâàíèÿ glacial savanna of the last Glacial period, namely peat- ðàçíûõ öåíîçîâ-àðõåòèïîâ, óíàñëåäîâàííûõ, âèäè- lands, park forests, halocoenoses and dry meadows. In ìî, îò ïåðèãëÿöèàëüíîé ñàâàííû ïðåäøåñòâîâàâøå- course of succession all these coenoses are transformed ãî ëåäíèêîâüÿ òîðôÿíûõ áîëîò, ëåñîïàðêîâ, ãàëî- into a single reference one, i.e. meadow coenosis. Bee- öåíîçîâ è ñóõèõ ëóãîâ. Âñå îíè â õîäå ñóêöåññèé tle faunal assemblages in the forest-steppe are charac- ïðåâðàùàþòñÿ öåíòðîñòðåìèòåëüíî â åäèíûé ýòà- terized by the most original and dynamically stable ëîí ëóãîâîé öåíîç. Ëóãîâûå ñîîáùåñòâà â ëåñî- composition and structure, occupying more than 70% ñòåïè îòëè÷àþòñÿ íàèáîëåå îðèãèíàëüíûì è óñòîé- of the zonal area with a wide range of habitats. There- ÷èâûì â äèíàìèêå ñîñòàâîì è ñòðóêòóðîé, çàíèìàþò fore the meadow coenoses, rather than the fragmentary áîëåå 70% ïëîùàäè çîíû â øèðîêîì äèàïàçîíå ìåñ- quasi-steppes and forest-like insular tree stands, repre- òîîáèòàíèé. Ïîýòîìó èìåííî îíè, à íå ôðàãìåíòàð- sent the indigenous element of the latitudal zone be- íûå êâàçèñòåïè è ëåñîïîäîáíûå êîëêè ïðåäñòàâëÿ- tween taiga and steppe. It makes more sense to refer to þò êîðåííîé ýëåìåíò øèðîòíîé çîíû ìåæäó òàéãîé the corresponding original biome as a meadow, rather è ñòåïüþ. Ñîîòâåòñòâóþùåé åé îðèãèíàëüíûé áèîì than steppe, one. ëîãè÷íåå èìåíîâàòü ëóãîâûì, à íå ëåñîñòåïüþ. 170 V.G. Mordkovich Introduction Ecological criteria enable to answer the question to what degree the composition and structure of insect Landscape ecology of pedobionts has always at- faunal assemblages of the forest steppe tree and grass tracted significant attention of soil zoologists, such as stands resembles the reference forest and steppe as- M.S. Ghilarov [1965] and his immediate followers, semblages. The issue becomes increasingly actual in including B.R. Striganova. The book about pedobiont respect to the global warming, which is often identified assemblages and their structure in the latitudal zones of with aridisation. In fact the global warming is quite a the West Siberian Plain is the most recent major gener- controversial phenomenon, and in different regions of alization in the field [Striganova, Poryadina, 2005]. the world may result either in aridisation or humidifi- In the system of those latitudal zones of particular cation of the environment. Judging by the meteorologi- interest is the forest-steppe zone as it is generally char- cal data of the recent decades, in the forest-steppe zone acterized as a marginal mosaic complex of biota at the of the West Siberian Plain the global warming appar- interface of forest and steppe. The latitudes occupied ently results in the drastic intensification of annual and by the forest-steppe display some extraordinary fea- seasonal climatic fluctuations [Beresneva, 2006], the tures in the gradient of environmental conditions from latter being quite pronounced even without any warm- the Equator to the Northern Pole: the broadest environ- ing. mental conditions range, the balance between evapora- Under such environmental conditions the assem- tion and precipitation, the balance between soil humifi- bling of insect species into the forest-steppe communi- cation and mineralization and very high natural soil ties, presumably, should be directed against the organ- fertility, etc. Thanks to all these the forest-steppe may isms with narrow specialization to hyper-humid or su- be regarded as a zone of environmental comfort for per-arid conditions, favouring the species that are tol- biota. As a result, species richness along the latitudal erant to a broad environmental range. To test this hy- gradient reaches its maximum in the forest-steppe. The pothesis we analyzed the taxonomical composition and total biodiversity of arthropods, comprising 90% of the ecological structure of a) predator ground beetles as- total fauna biodiversity, amounts to 4,000 species, that semblages, that are abundant and diverse in the forest, is 1.52.0 times higher than in the neighbouring forest forest-steppe and steppe zones, and b) sapro-and phy- and steppe zones [Mordkovich et al., 2002]. tophagous darkling beetles as most of them, excepting What is the mechanism causing such a high rate of forest and water-dwelling species, are considered to be species richness? The most common concept tends to indicative of aridisation. attribute the latter to the result of a mere summation in the forest-steppe zone of all the species expanding Materials and methods from the north and from the south. Areal analysis seems to confirm this view as no less than 80% of the forest- The study region. The study was carried out in the steppe biota species, and primarily insects, enjoy po- Plains in the south of West Siberia, Russia (Baraba and lyzonal areas, embracing forest-steppe and forest zones Kulunda) and in Central Kazakhstan (Atbasar, Tengiz or forest-steppe and steppe zones, or even all three and Balkhash Plains, Kazakhstan) in the geographical ones. The major issue here is that there are few reasons region within 6544°N and 7080°E, embracing 3 taiga to consider such species as truly autochtonous forest- subzones (the northern, middle and southern ones), 3 steppe ones, intruding to the north and south, and vice forest-steppe subzones (northern, typical and southern versa. ones) and 3 steppe subzones (arid-chernozemic, The occurrence of endemic species can serve as an kastanozemic dry and deserted ones), as well as in the objective criterion for faunas specificity. There are northern subzone of the temperate desert (Cis- and endemic species in the forest-steppe zone. Analyzing Trans-Balkhash areas). A typical catena with represen- the ground beetles and other insects faunas in the East tative ecosystems (eluvial, EL, transit, TR, and accu- European forest-steppe, K.V. Arnoldi [1965] observed mulative, AC) were chosen. Typical zonal biogeo- dozens of endemic species. According to Siberian en- coenoses that had never been ploughed, regularly hayed, tomologists, the degree of endemism for the West Si- overgrazed or otherwise subjected to anthropogenic berian forest-steppe fauna ranges from 12 to 1015% land use impact were chosen as reference ecosystems. for various taxa [Mordkovich et al., 2002]. Nonethe- Beetle sampling. Ground beetles (Coleoptera: Cara- less, arealogical argumentation is not sufficient to infer bidae) and darkling beetles (Coleoptera: Tenebrion- the indigenous character of the forest-steppe entomo- idae) were samples using pitfall traps of 12 cm diame- logical assemblage. ter. Ten traps were placed at each site. Trapping was Alongside with the size and contour of the area of conducted monthly since May till August during con- crucial importance