Arachnologische Mitteilungen 58

Spiders from steppes of Pláně Nature Monument (Czech Republic) 87 by sweeping. Spiders collected by pitfall trapping consisted mainly of actively hunting guilds such as ground and other hunters and several species of specialists from the family Dys- deridae (Fig. 2). The most abundant species were Alopecosa cuneata with 2603 individuals and Pardosa palustris with 1884 individuals. The next dominant species were Alopecosa farinosa with 537 individuals and Alopecosa pulverulenta with 487 individuals. The aforementioned spiders of the genus Alopecosa are typical for open steppe habitats (Buchar & Růžička 2002). Alope- cosa striatipes , which is very rare in the Czech Republic and occurs only in the south-eastern part of the country (Kůrka et al. 2015), was caught from a high number of 387 individu- als, mostly in Site 1 and can be considered abundant in the Pláně NM. The next result was the significantly high abun- dance of Thanatus arenarius , which is rare and only found in warm areas of central and south-eastern parts of the Czech Republic (Buchar & Růžička 2002, Košulič & Hula 2014). However, in the study area, a high number of 704 individuals were found mostly at Site 2. Both Sites 1 and 2 are typical of sparse herbaceous vegetation and stones/rocks on shallow soil, thus meeting the ecological requirements of these species (Ratschker & Roth 2000). The family Linyphiidae was the most dominant with 32 species recorded (Tab. 1). However, only a few individuals of each species were caught. Agyneta rurestris was found to be quite common due to the non-restriction of ecological re- quirements and aerial dispersal using silk. The next species- rich families were Gnaphosidae (22 species), Lycosidae (14 species), Salticidae (12 species) and Theridiidae (12 species). The suitability for xerothermic herb-dwelling spiders is cor­ roborated by the high abundance of 149 individuals of the scarce Evarcha laetabunda , which inhabits herbs on rock steppes (Buchar & Růžička 2002). The Lycosidae with 7104 and Gnaphosidae with 1367 individuals were the most abun­ dant families. From the family Lycosidae, there were also spe- cies that are typical of forest edges (Buchar & Růžička 2002): Pardosa lugubris and Trochosa terricola were abundantly found at Site 3, which is adjacent to a forest. At Site 3, the xerothermic species Alopecosa trabalis , which inhabits forest steppes and light south-exposed forests (Buchar & Růžička 2002), was also abundant (260 individu- als). Site 3 is a good example of a xerothermic slope habi- tat with a south-eastern exposure that is adjacent to a forest, hence it provides suitable conditions for both typical steppe species and species typical of ecotones like forest edges. In the family Gnaphosidae there were a number of regionally important rare/scarce species like Civizelotes pygmaeus , Dras- syllus pumilus, Haplodrassus dalmatensis , Micaria formicaria , Zelotes aeneus , Zelotes aurantiacus , Zelotes electus and Zelotes longipes , which all live under stones on rock steppes (Buchar & Růžička 2002). Their presence is due to the large amount of scattered small rocks and stones which serve as shelter for these ground hunters. For the record, these species are mostly found in their northernmost territory of distribution in Sou- thern Moravia. Zelotes electus was abundantly found at Site 1 (84 individuals) and Site 2 (86 individuals), whereas Zelotes auranticaus was found at Site 3 (24 individuals). Site 2 had a xeric character while Site 3 had a lower amount of sparse vegetation and was adjacent to the forest. Both species have similar habitat preferences, therefore, it may be an effect of competition like that of other related species (Michalko et al. 2016). In general, a valuable arachnofauna composition inclu- ding 36 rare and scarce species (7 %) belonging to the Red List of Czech spiders (Řezáč et al. 2015) were discovered. It includes mainly species whose occurrence is typical of open steppes and grasslands at the early stages of succession: CR (critically endangered): Alopecosa striatipes; EN (endangered): Drassyllus pumilus ; VU (vulnerable): Neottiura suaveolens , Tri- choncus affinis , Trichopterna cito , Cheiracanthium oncognathum , Phrurolithus minimus , Haplodrassus dalmatensis , Micaria formi- caria , Civizelotes pygmaeus , Thanatus arenarius , Evarcha laeta- bunda , Talavera petrensis . It should be noted that the total spider diversity (154 species) was relatively high and this significantly enriches the surveyed area due to new findings. Altogether, 230 spe- cies of spiders are now known from the study area (faunistic square 6663) due to the presented faunistic study and pre- viously published data (Křížová 2001). The occurrence of a wide spectrum of species also confirms the importance of xeric grasslands within the Pláně NM as a refuge for spider communities in the intensified agricultural landscape of Mo- ravia.These stepping stones are very important in the overall biodiversity of arthropods in the modern landscape (Košulič et al. 2014, Šálek et al. 2018). The results also suggest that Fig. 2: Guild composition of spi- ders in steppe habitats of the Pláně NM 45 40 35 30 25 20 15 10 5 0 Species number Ground hunters Other hunters Sheet web Space web Specialists Ambush hunters Orb web Sensing web