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Faunal surveys were performed in Mtirala National Park (Georgia, Caucasus). Oribatid mites were collected from four microhabitats (soil, moss, litter, decaying wood) at 15 locations from 250 to 1000 m a.s.l. Forest types included walnut (Juglans regia) plantations, mixed chestnut (Castanea sativa) forests, and beech (Fagus orientalis) forests. Our surveys revealed 124 species of oribatid mites. One species, Feiderzetes latus (Schweizer, 1956), is new for Georgian fauna and was found only in decaying beech wood at various stages of decay. Chamobates voigtsi (Oudemans, 1902) was present in all types of habitats and dominated in soil and litter samples. Liebstadia pannonica (Willmann, 1951) was numerous in decaying wood, and Mycobatidae were abundant in moss. Other species were present in moderate quantities. Simpson s index of diversity (1 D) revealed low to moderate diversity in nearly all samples, with sampling completeness of about 80%. Hierarchical cluster analyses showed the highest similarity between the soil and litter fauna, with dead wood being the most distinct, indicating special communities of oribatid mites exist there. No pattern of faunal changes along the altitudinal gradient was observed.

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The key subject of this investigation was to study distribution patterns of oribatid mites in the main habitats and ecosystems of Kolkheti National Park. Oribatida were studied in 1) sand dunes, 2) Juncus bogs, 3) flooded alder (Alnus barbata C. A. Mey) forests, and 4) humid alder forests. Sampling was conducted in November 2009 at 18 sites along three transects. For exploratory analysis, we applied clustering techniques. Correlation between species number, density and humus was calculated. Chao1 statistics were used to estimate the completeness of sampling. Forty six oribatid species were recorded. The highest Shannon diversity index was registered for alder forests, whereas the lowest index was observed for dunes. In sand dunes 16 species were found, three of which occurred only in this landscape. In Juncus bogs, 32 species were recorded, and 16 were unique to this landscape, including bog specific Zetomimus furcatus (Warburton & Pearce, 1905), Euzetes globulus (Nicolet, 1855) and Punctoribates manzanoensis Hammer, 1958. Twenty two species were found in flooded forests, seven being exclusive. Ten species were recorded in humid forests, and Metabelbella macerochaeta Bulanova-Zachvatkina, 1965 and Eremobelba geographica Berlese, 1908, typical inhabitants of humid forest soils, appeared as exclusive species. Faunal comparisons among landscapes show high similarity between dune and bog oribatid mite communities, followed by flooded and humid alder forests. In dunes and bogs, total faunal density is determined by euryecological species, whereas in alder forests density was determined by high abundance of humid and extremely humid specific species.

Comparison of Earthworm (Lumbricidae) and Oribatid Mite (Acari, Oribatida) Communities in Natural and Urban Ecosystems. Murvanidze M., Kvavadze E., Mumladze L., Arabuli T. -This study investigates earthworm and oribatid mite communities in urban, semi-natural and natural ecosystems of Tbilisi (Georgia). Ten species of earthworms and 100 species of oribatid mites were registered in 45 soil samples. Two species of oribatid mites, Microzetes auxilaris Grandjean, 1936 and Multioppia laniseta Moritz, 1966, are new for the Caucasian fauna. We hypothesized that species number and abundance of invertebrate animals tend to decrease from natural to urban ecosystems. The hypothesis was supported only partially. Number of species of oribatid mites and earthworms decreased together with increase of urbanization, whereas abundance showed no significant changes due to high density of stress tolerant and ubiquitous species in urban sites. Accordingly, species abundance is considered to have minor indicatory value. Our studies support ecological "time-hypothesis" in a way that older (natural) sites were presented with more diverse fauna than recent (urban) ones. Statistical analyses showed that studied ecosystems should be grouped in two rather than three categories: in urban and natural ones.K e y w o r d s: earthworms, oribatid mites, urbanisation, ecological "time-hypothesis", Tbilisi.Ñðàâíåíèå ñîîáùåñòâ äîaeäåâûõ ÷åðâåé (Lumbricidae) è ïàíöèðíûõ êëåùåé (Acari, Oribatida) â ïðè-ðîäíûõ è óðáàíèçèðîâàííûõ ýêîñèñòåìàõ. Ìóðâàíèäçå Ì., Êâàâàäçå Ý., Ìàìëàäçå Ë., Àðàáóëè Ò. - ñòàòüå ïðåäîñòàâëåíû ðåçóëüòàòû èññëåäîâàíèÿ ñîîáùåñòâ äîaeäåâûõ ÷åðâåé è ïàíöèðíûõ êëå-ùåé â óðáàíèçèðîâàííûõ, ïîëóïðèðîäíûõ è ïðèðîäíûõ ýêîñèñòåìàõ ã. Òáèëèñè (Ãðóçèÿ).  45 ïî÷âåííûõ ïðîáàõ áûëè íàéäåíû 10 âèäîâ äîaeäåâûõ ÷åðâåé è 100 âèäîâ ïàíöèðíûõ êëåùåé. Äâà âèäà êëåùåé -Microzetes auxilaris Grandjean, 1936 è Multioppia laniseta Moritz, 1966 ÿâëÿþòñÿ íîâû-ìû äëÿ ôàóíû Êàâêàçà. Ìû ïðåäïîëîaeèëè, ÷òî êîëè÷åñòâî è ïëîòíîñòü íàñåëåíèÿ áåçïîçâîíî÷-íûõ äîëaeíû óìåíüøàòüñÿ îò ïðèðîäíûõ ê óðáàíèçèðîâàííûì ýêîñèñòåìàì. Íàøà ãèïîòåçà ïîä-òâåðäèëàñü ÷àñòè÷íî. Êîëè÷åñòâî âèäîâ äîaeäåâûõ ÷åðâåé è ïàíöèðíûõ êëåùåé ñîêðàòèëîñü ñ óâå-ëè÷åíèåì ñòåïåíè óðáàíèçèðîâàííîñòè ñðåäû, òîãäà, êàê ïëîòíîñòü íàñåëåíèÿ ñóùåñòâåííî íå ìåíÿëàñü èç-çà âûñîêîé ïëîòíîñòè îòäåëüíûõ óáèêâèñòîâûõ è òîëåðàíòíûõ ê ñòðåññàì âèäîâ. Ñîîòâåòñòâåííî ñ÷èòàåì, ÷òî ïëîòíîñòü íàñåëåíèÿ íå èìååò áîëüøîãî èíäèêàöèîííîãî çíà÷åíèÿ. Íàøè ðåçóëüòàòû ïîäòâåðaeäàþò ýêîëîãè÷åñêóþ «ãèïîòåçó âðåìåíè» òåì, ÷òî áîëåå ñòàðûå (ïðè-ðîäíûå) ó÷àñòêè áûëè ïðåäñòàâëåíû áîëåå ðàçíîîáðàçíîé ôàóíîé, ÷åì áîëåå íîâûå (óðáàíèçè-ðîâàííûå). Ñòàòèñòè÷åñêèé àíàëèç ïîêàçàë, ÷òî èçó÷åííûå ýêîñèñòåìû äîëaeíû áûòü ñãðóïïè-ðîâàííû ïî äâóì, à íå ïî òðåì êàòåãîðèÿì: ïî ïðèðîäíûì è óðáàíèçèðîâàííûì.