Ardelean, Gavril (szerk.): Satu Mare. Studii şi comunicări. Seria ştiinţele naturale 6. (2005)
The epigeic spider communities (araneae) of three winter wheat fields in Gherla region (Cluj district)
THE EPIGEIC SPIDER COMMUNITIES (ARANEAE) OF THREE WINTER WHEAT FIELDS IN GHERLA REGION (CLUJ DISTRICT) KINGA FETYKÓ Unirii Sfr. IA/28, Sighetu Marmatiei, Maramureş, 'Romania E-mail: kinga78@freemail.hu Satu Mare - Studii şi Comunicări Ştiinţele Naturale — Voi. VI (2005) Rezumat Lucrarea de faţa prezintă un studiu al comunităţilor de păianjeni din grâul de toamnă. Studiul a fost realizat în vara anului 2001, cu o frecvenţă de 7 zile, mai-august, folosind capcane tip Barber. Au fost colectate un număr de 4540 păianjeni adulţi reprezentând 57 de specii din 12 familii. Familia Lycosidae s-a dovedit a fi eudominant, reprezentat fiind cu 17 specii, din care Pardosa agrestis a fost cea mai dominantă specie epigeicagrobiontă. în fiecare caz, zona marginală a terenurilor cultivate cu grâu de toamnă, a avut un profil de diversitate mai crescută în comparaţie cu celelalte zone investigate. Summary The epigeic spider communities of three winter wheat fields were investigated. A total of 4540 adult individual of 57 spider species from 12 families were collected from May to August 2001 with 7 day frequency. The eudominant family was Lycosidae represented with 17 species, and Pardosa agrestis was the dominant epigeic agrobiont species. Diversity analyses reveal a higher diversity profile of every margin rows in each sampling siteintroduction Investigations of the spider community of arable lands, including winter wheat (De Clerq 1984, Alderweireldt 1993, 1987; Basedow et al. 1991; Gajdos 1992; Kromp & Steinberg 1992; Sunderland & Topping 1993; Tóth 1997, Kiss et al. 1998;), reveal a special community structure characterized by a limited number of dominant species called agrobiont species. Agrobiont spiders were able to adapt themselves to these highly variable conditions. Therefore they are capable to form larger populations in cultivated fields than in other undisturbed natural habitats (Luczak 1979; Nyffeler 1982). To estimate the most relevant agrobiont spider species in this Eastern region of Europe we had studied several published papers in this matter. In Hungary, Slovakia and Austria the most abundant agrobiont species were from the family Lycosidae: Pardosa agrestis (Westring 1861), Pardosa prativaga (Koch 1870) and Trochosa ruricola (De Geer 1778). In the field margin Trochosa terricola (Thorell 1856) and Aulonia albimana (Walckenaer 1805) were presented the more abundant lycosid species. Other well represented spider families were Linyphiidae and Thomisidae with to two agrobiont species: Oedothorax apicatus (Blackwall 1850) and Xyticus kochi (Thorell 1872) (Gajdos 1992, Kromp & Steinberg 1992, Tóth 1997). A comparative analysis of epigeic spider assemblage of winter wheat and their adjacent margins from Hungary showed that the species diversity was higher at the field margin than in the field (Tóth & Kiss 1999). These field margins, hedgerows are often used for diversification of agricultural landscapes, but they are also important in overwintering as refuge habitats for beneficial arthropods like spiders. Non-crop spiders also live in these microhabitats enhancing higher species diversity than in the centre of the field (Alderweireldt 1993, Kromp & Steinberg 1992). The Romanian rural agricultural landscape is partly characterized by small-sized agricultural fields cultivated with different types of cereals and vegetables. Although spider assemblages in various habitats have been studied in Romania (Fuhn & Oltean 1969, Niculescu —Burlacu 1968, Oltean 1967, Urák 2001), but no former studies on epigeic spider communities of arable lands were carried out. The objectives of the present study were: (1) Describe the epigeic spider fauna of three winter wheat field and their margins. (2) Investigate dominancy structure of the epigeic spider communities. (3) Investigate the diversity of different sampling rows of the three winter wheat field. Material and methods The study fields were in three locations of the arable land of Livada and Iklod villages (near Gherla city, Cluj district). The three sites data: 1) Livada 1:- 0.8 ha (200m x 50m), treated with mineral fertilizer and herbicide in spring of 2001 2) Iklod 2: - 0.5 ha (100m x 50m), untreated, weeds were removed manually in spring 3) Iklod 3: - 0.96ha (120m x 80m), untreated Each winter wheat field had a common margin with an alfalfa field and the density of weeds was estimated in every sampling row. Spiders were collected by pitfall trapping. The traps consisted of two plastic cups, one inside the other, both with an upper diameter of 10 cm, containing 20% vinegar and a few drops of detergent. These traps were arranged in three rows: ■ -6 traps on the field margin (alfalfa was the neighbour field) 40
