Arthropoda Selecta 17 (34): 175184 © ARTHROPODA SELECTA, 2008 Fauna and ecology of gnaphosid spiders (Aranei: Gnaphosidae) in clay semidesert of Western Kazakhstan Ôàóíà è ýêîëîãèÿ ãíàôîçèä (Aranei: Gnaphosidae) ãëèíèñòîé ïîëóïóñòûíè Çàïàäíîãî Êàçàõñòàíà T.V. Piterkina1 & V.I. Ovtcharenko2 Ò.Â. Ïèòåðêèíà1, Â.È. Îâ÷àðåíêî2 1 Institute of Ecology and Evolution, Russian Academy of Sciences, Leninsky Prospect 33, Moscow 119071 Russia. E-mail: [email protected] Èíñòèòóò ïðîáëåì ýêîëîãèè è ýâîëþöèè ÐÀÍ, Ëåíèíñêèé ïðîñïåêò, 33, Ìîñêâà 119071 Ðîññèÿ. 2 Hostos Community College of the City University of New York, New York 10451 USA. E-mail: [email protected] Õîñòîñ Êîëëåäæ Ãîðîäñêîãî Óíèâåðñèòåòà ã. Íüþ-Éîðê, Íüþ-Éîðê 10451 ÑØÀ. KEY WORDS: ground spiders, fauna, structure of population, Caspian Lowland, desert steppe, climate changes. ÊËÞ×ÅÂÛÅ ÑËÎÂÀ: ãíàôîçèäû, ôàóíà, ñòðóêòóðà íàñåëåíèÿ, Ïðèêàñïèéñêàÿ íèçìåííîñòü, îïóñòûíåí- íûå ñòåïè, èçìåíåíèÿ êëèìàòà. ABSTRACT. Gnaphosids of 41 species of 14 gen- íàíòíû è âûðàâíåíû. Ñîîáùåñòâà ãíàôîçèä ëåñî- era were collected in the clay semidesert in the envi- ïîñàäîê ñèëüíî îáåäíåíû, õàðàêòåðíî íàëè÷èå îä- rons of Dzhanybek Research Station, West Kazakh- íîãî-äâóõ âûñîêîîáèëüíûõ âèäîâ. Òàêæå îöåíåíà stan. A zoogeographical analysis of gnaphosid popula- ñòåïåíü áèîòîïè÷åñêîé ïðèóðî÷åííîñòè âèäîâ ãíà- tion shows that the main role in the formation of the ôîçèä. Ñðàâíåíèå ñîâðåìåííûõ äàííûõ ñ ìàòåðèà- modern fauna is performed by species that are locally ëàìè 20-ëåòíåé äàâíîñòè ïîêàçàëè èçìåíåíèÿ â ñî- or widely inhabiting the territory of the Ancient Medi- ñòàâå è ñòðóêòóðå íàñåëåíèÿ ãíàôîçèä çîíàëüíûõ terranean. They comprise two-thirds of the entire gna- áèîòîïîâ. Âîçìîæíî, ýòî ñâÿçàíî ñ ðåçêèìè òåìïà- phosid population of the region. The rest one-third are ìè «ñìÿã÷åíèÿ» êëèìàòà â ðåãèîíå â ïîñëåäíèå äå- widespread species. The gnaphosid communities of ñÿòèëåòèÿ, âûçâàâøèìè èçìåíåíèÿ â âîäíîì ðåæè- native biotopes (microelevations and microdepressions) ìå ïî÷â, ÷òî, â ñâîþ î÷åðåäü, ïîâëèÿëî íà ðàñòè- are the most diverse. The population of the artificial òåëüíîñòü è æèâîòíîå íàñåëåíèå. associations is much poorer and less equalized. All associations studied have their own complexes of typi- Introduction cal species. The comparing of present-day data and materials obtained 20 years ago shows some changes Gnaphosidae is a spider family that includes about in composition and structure of gnaphosid population 1990 species of 114 genera in the world [Platnick, of native biotopes. Probably it is connected with a 2007]. With rare exception, they are ground and litter- rapid pace of smoothing of the climate of the region dwellers, diurnal or nocturnal wandering hunters. As a during recent decades that caused changes in water rule, representatives of the family are thermophilic. On regime of soils that in its turn influenced the plant and the latitudinal gradient from the arctic tundra to deserts, animal communities. the gnaphosids show an increase in their abundance and diversity. In the semidesert, where our material ÐÅÇÞÌÅ.  ãëèíèñòîé ïîëóïóñòûíå Çàïàäíîãî was collected, Gnaphosidae is one of the leading fami- Êàçàõñòàíà (îêðåñòíîñòè Äæàíûáåêñêîãî ñòàöèî- lies. The Gnaphosidae occupies a special position íàðà) ñîáðàí 41 âèä ãíàôîçèä, îòíîñÿùèõñÿ ê 14 among semiarid ground-dwellers displaying all fea- ðîäàì. Çîîãåîãðàôè÷åñêèé àíàëèç ïîêàçàë, ÷òî âå- tures of biological progress: high taxonomical diversi- äóùóþ ðîëü â ôîðìèðîâàíèè ôàóíû ãíàôîçèä ðå- ty, wide adaptive radiation, high abundance during all ãèîíà ñûãðàëè âèäû, øèðîêî èëè ëîêàëüíî íàñåëÿ- vegetative period, and inhabitation of all types of envi- þùèå òåððèòîðèþ Äðåâíåãî Ñðåäèçåìüÿ. Îíè ñî- ronment. That is why the Gnaphosidae was chosen as a ñòàâëÿþò äâå òðåòè ôàóíû. Îñòàâøàÿñÿ ÷àñòü îáðà- model family for our investigations in clay semidesert çîâàíà øèðîêîàðåàëüíûìè âèäàìè. Íàèáîëåå áîãà- of northern Caspian Sea Lowland. The place studied is òî âèäàìè íàñåëåíèå çîíàëüíûõ áèîòîïîâ (ìèêðî- located at the point of contact of several zoogeographi- ïîâûøåíèé è çàïàäèí), èõ ñîîáùåñòâà ïîëèäîìè- cal provinces, so that it was interesting to see what Printed in 2009. distributional elements took part in the formation of the 176 T.V. Piterkina & V.I. Ovtcharenko modern spider fauna of this territory. In addition, the About 3.000 spider specimens were studied with 1.700 spatial structure of the gnaphosid communities was of these spiders being mature. studied. As well, having an opportunity to examine the The biotopical adherence of species was calculated material collected in this place 20 years ago, we were with the help of the Pesenkos coefficient (F ) [Pesen- ij able to observe the changes of gnaphosid population of ko, 1982] which represents a mathematical transforma- native biotopes over this period. tion of the share of this species in this biotope to its share in all other biotopes: Study area and methods F = (n /N n /N) / (n /N + n /N), ij ij j i ij j i where n number of specimens of i-species in ij Spiders were collected in the territory of the Dzh- samples from j-biotope with total volume N ; n num- j i anybek Research Station of the Institute of Forestry, ber of specimens of i-species in all other biotopes with Russian Academy of Sciences (49o23'N, 46o48'E). This total volume N. station is located in the westernmost point of Kazakh- The single findings of the species were left out of stan, just near the border of Volgograd Area of Russia. the account. The location studied has some interesting features: first, The value of the coefficient changes from 1 (abso- it is situated in the belt of clay semidesert that occupies lute avoidance) up to +1 (absolute adherence). a narrow strip between the deserts of Central Asia in We distinguish the following intervals of the coeffi- the south and the Eurasian steppes in the north; second, cient value: not so long ago by geological criteria, sea covered this 0.7 < F < 1.00 high level of adherence to the ij territory. Therefore, the process of formation of fauna biotope; is still in progress. 0.3 < F < 0.7 preference of the biotope; ij The area studied is a flat plain in the northwest 0.3 < F < 0.3 indifference to the biotope; Caspian Lowland. From the Palaeozoic period until the ij F <0.3 avoidance of the biotope. recent past, the Caspian Lowland was repeatedly cov- ij For comparing the populations, we used Czekanows- ered with waters of ancient seas and more recent seas ki Sorensens Index of Similarity of Species Compo- [Doskatch, 1964]. The last Khvalyn transgression of sition [Pesenko, 1982]: the Caspian Sea occurred in the Upper Quaternary I = 2a / (a+ b)+(a + c), period. Hence, the sea retreated from the Dzhanybek CS plain only 3779 thousand years ago [Varushchenko et where a number of common species for both al., 1980]. As the sea retreated, the continental climate samples, was set and native semidesert landscapes began form- b number of species distinctive for sample 1, ing. Different soil-forming processes in addition to the c number of species distinctive for sample 2; active burrowing work of the ground squirrel (Citellus and Index of Similarity of Structure of Populations: I = min (p , p ), pygmaeus Pall.) resulted in the mosaic landscape, so CS b ∑ ij ik where p share of i-species in j-sample, typical for clay semidesert [Abaturov, 1985]. It is char- ij acterized by a complex pattern of soils and vegetation p share of i-species in k-sample. ik and is composed of mosaics of desert and steppe plant In view of high specificity of spring population and communities. Microelevations are desert biotopes with the absence of spring samples in 1984, we used for Kochia prostrata and Artemisia pauciflora associa- comparison only summer and autumn collections. tions on solonetzic soils. Microdepressions are steppe biotopes with forb-grass vegetation (Stipa spp., Festu- Results and discussion ca valesiaca, Agropyron cristatum, etc.) on dark chest- nut and meadow chestnut soils. Besides native associa- Taxonomical and zoogeographical structure. tions, there are areas of 50-year-old plantations in the Gnaphosids of 41 species of 14 genera (Table 1) were territory of the Station. collected in the clay semidesert on the territory of the The spiders were collected in 1984 (JuneSeptem- Dzhanybek Station. The genus Zelotes is the richest by ber) by Kirill G. Mikhailov and in 20042005 (April its diversity; it is represented by 11 species. The other October) years by Tatyana V. Piterkina in 2 native genera are much poorer. Seven genera are represented communities (microelevations and microdepressions) by 24 species. The remaining six genera are repre- and 3 artificial ones: oak (Quercus robur) forest belts, sented by single species. an oak community in local park, and elm (Ulmus pum- In the typology of ranges we follow terminology ila) forest belts. Both in 1984 and in 20042005, the of O.L. Kryzhanovskii [2002] with some modifica- same methods were used: pitfall trapping and manual tion. We consider the steppe zone of Eurasia to be the sorting of serial soil-litter samples (0.25x0.25 m). A subregion of the Ancient Mediterranean region. To 4% formaldehyde solution was applied as fixative to generate the distribution patterns of gnaphosid spi- pitfall trapping. The traps were checked every 57 ders collected at Dzhanybek, we selected 10 types of days. Soil-litter samples were taken in 10 replications ranges and united them into 3 groups (Table 2). The 3 every 10 days. groups are: Over the course of the study total of 15.000 pitfall 1. Widespread (includes Circum-Holarctic, Trans- traps per day were set, 570 soil-litter samples taken. Palearctic and West-Central-Palearctic patterns); Fauna and ecology of gnaphosid spiders in clay semidesert of Western Kazakhstan 177 Table 1. Checklist of gnaphosids of the clay semidesert of Western Kazakhstan. AM Ancient Mediterranean, CH Circum-Holarctic, E Conventionally endemic, EAM East Ancient Mediterranean, EuAM Euro-Ancient Mediter- ranean, S Scythian, TP Trans-Palearctic, WAM West Ancient Mediterranean, WCP West Central Palearctic, WS West-Scythian.