Arachnologische Mitteilungen 58

Spiders from steppes of Pláně Nature Monument (Czech Republic) 91 the study area serves as an important refuge for thermophilic spiders that are normally not present in this otherwise colder mesophytic region. This is supported by the high occurrence of typically Pannonian species, for whom this area represents their northernmost distribution limit (Buchar & Růžička 2002, Kůrka et al. 2015). Species richness estimation The species accumulation curve did not reach the asymptote and showed a rising character, which means that the spider diversity was not sampled in their entirety and the diversity is expected to be significantly higher than the 154 species collected. Jackkni- fe 1 estimator calculated a total estimated richness of 194.15 ± 6.26 (standard deviation) species for the study area (Fig. 3). Faunistically remarkable species All the species mentioned below belong to rare, xerothermic species and the Pláně NM is their northernmost distribution not only in South Moravia, but even in Moravia as a whole. Aside from the Thanatus arenarius, the following findings are the first for the faunistic square 6663. Dysdera moravica (Fig. 4 a) This species belongs to a large complex of morphologically similar species which mainly occur in northern Italy and in the northwest of the Balkan Peninsula (Řezáč et al. 2012). Dysdera moravica is European species that occurs in Serbia, Croatia, Romania, Hungary, Slovakia, Austria, Germany and the Czech Republic (Nentwig et al. 2019). In the Czech Re- Fig. 3: Number of spe- cies in 48 samples in relation to the number of species expected by a Jackknife1 estimator in the Pláně NM Species Site 1 Site2 Site 3 Occurence level Habitat preferences Thermo preferences Conservation status Sparassidae Micrommata virescens (Clerck, 1757) . . 1 VA C, SN M – Philodromidae Philodromus albidus Kulczyński, 1911 . . 1 A C, SN, D T, M – Philodromus cespitum (Walckenaer, 1802) . 2 . VA C, SN, D T, M – Philodromus dispar Walckenaer, 1826 1 . 1 S C, SN T , M – Thanatus arenarius Thorell, 1872 318 362 24 R C T VU Thanatus formicinus (Clerck, 1757) 101 39 34 A C, SN T, M LC Thanatus striatus C. L. Koch, 1845 1 . . A C, SN (T), M LC Tibellus oblongus (Walckenaer, 1802) 1 . . S C, SN T, M – Salticidae Euophrys frontalis (Walckenaer, 1802) . 1 . A C, SN T, M – Euophrys petrensis C. L. Koch, 1837 5 4 3 S C, SN T, M VU Evarcha arcuata (Clerck, 1757) 3 1 7 VA C, SN T, M – Evarcha laetabunda (C. L. Koch, 1846) 68 42 39 S C T , (M) VU Heliophanus cupreus (Walckenaer, 1802) 1 1 2 A C, SN T, M – Heliophanus flavipes (Hahn, 1832) 12 6 17 A C (T), M – Hypositticus pubescens (Fabricius, 1775) 1 . . VA C, SN, A M – Pellenes tripunctatus (Walckenaer, 1802) . 1 . S C T LC Phlegra fasciata (Hahn, 1826) 34 21 35 A C, SN T, M – Sibianor aurocinctus (Ohlert, 1865) 1 . . A C, SN T, M LC Talavera aequipes (O. P.-Cambridge, 1871) 3 3 2 A C , SN T, M – Talavera aperta (Miller, 1971) 1 . . R C , SN T, M LC Number of species 220 200 180 160 140 120 100 80 60 40 20 0 Samples Observed Richness Estimated Richness (Jack 1) 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48