Spiders (Araneae) of Chernivtsi City (Ukraine)

: The spiderfauna of buildings and other urban habitats (city parks, green areas of industrial enterprises, and housing estates) of Chernivtsi city was surveyed. In the period 2002-2011, 21 2 species belonging to 26 families were recorded. Previous studies found a total of 1 73 species of spiders belonging to 26 families from the territories which are now included in the city limits of Chernivtsi. Currently,the total spider species list for Chernivtsi includes 260 species of 30 families, of which 1 25 species (21 families) were recorded both by earlier researchers and by ourselves. The most important reasons for changes in urban spider assemblages are as follows: species habitat change, introduction of alien species,and description of new species unknown in the late 1 9th - early 20th centuries.

Urban habitats are becoming increasingly dominated by human-related factors and processes (GRIMM et al. 2000); yet most ecological studies focus on more natural and less human-altered ecosystems (SHOCHAT et al. 2004).Recent studies of the effect of urbanization on species composition show that urbanization can increase or decrease species richness, depending on the taxonomic group, the spatial scale of analysis, and the intensity of urbanization (McKiNNEY 2008).Certain studies focusing on changes in spider assemblages in urban habitats were undertaken during the last decades (KRZYZANOWSKA et al. 1981, AnTOV et al. 2004, ShOCHAT et al. 2004, HORVÄTH et al. 2010, VARET et al. 2010).Yet, we do not know enough about the causes of changes in spider assemblages in urban environments.Some of them are due to alien spider species introduced to Europe ( KOBELT &NENTWIG 2008).Habitat structure and productivity were shown to influence spider diversity and abundance in urban environments (SHOCHAT et al. 2004), as well as fragmentation of natural habitats due to urbanization (Gibbs & Stanton 2001, Gibb & Hochuli 2002).However, changes in spider assemblages over time and under increasing urbanization are still poorly understood.

Material and methods
The material treated in this paper was collected in 2002-2011 within Chernivtsi city.Chernivtsi is the administrative centre of the Chernivtsi Region in western Ukraine; its population is 240,000 people.The city's area is 153 km^ (the range of longitude is N 48°14'44.56"-48°23'53.55"; the range of latitude is E 25°49'59.96"-26°2'5.46";the range of altitude is 151-510 m a.s.L).The city is situated on the river Prut.According the physiographic subdivision by MARYNYCH et al. (2003), this area belongs to the Ukrainian Carpathians Mountain Region.We collected the material using different methods (hand collecting, pitfall traps, sweeping with a net, and beating) in various urban habitats such as forests and open patches at the city's edge, city parks, green areas of industrial enterprises and housing estates, and buildings.The largest fraction of spider specimens from semi-natural habitats in Chernivtsi was collected by pitfall traps.The traps, with a diameter of 7 cm, were placed in a line, about 6 meters apart from each other and contained ethylene glycol as a preservative; traps were opened during the schedules shown below, and were emptied twice a month.A description of the city parks was given by FE-DORIAK et al. (2010a); the green areas of industrial enterprises and other urban habitats were analyzed by Fedoriak et al. (2010b).A total of 2496 adults and 499 juveniles (of which 155 were identifiable to species level) were captured by pitfall traps from the 21 localities.
We also collected 499 adults and 1191 juveniles (231 identifiable to species level) inhabiting the trees Aesculus hippocastanum L., Tilia cordata Mill., Picea abies (L.) Karst, Thuja occidentalis L., 2 ind Acer negundo L. during the periods May to October 2006-2008 from the aforementioned city parks and from planted trees on both sides of the streets J. Hlavka, Golovna, Chervonoarmiyska, Kyiivska, Komarova, Korduby, L. Ukrainka, and Y. Fedkovych.Spiders from tree trunks included 197 adults and 576 juveniles (100 identifiable to species level) captured by hand collecting.A total of 302 adults and 615 juveniles (131 identifiable to species level) were collected from lower branches of trees by beating.Other spider specimens from different trees -171 adults and 534 juveniles (79 identifiable to species level) -were collected in localities such as Tsetsyno Landscape Conservation Area, the Botanic Garden of Chernivtsi University, and public gardens in Cathedral Square and Chervonoarmiyska str.
A total of 43 adults and 647 juveniles (159 identifiable to species level) were obtained from birds' nests collected from trees in different parts of the city.Additionally we used collecting methods such as hand-sorting litter samples and sweeping from nearly all the mentioned localities at different time periods as well as from the bank sediments of the river Prut; using these methods we caught a total of 476 adult specimens.
In this paper, we also include material collected from different indoor habitats such as the aforementioned industrial enterprises, multi-storey apartment buildings, and greenhouses.The characteristics of buildings and study methods have been already published by Fedoriak et al. (2010c).A total of 7959 specimens of spiders from buildings were collected: 2995 adults and 4964 juveniles (4464 identifiable to species level).
We also assembled data on urban spiders inhabiting Chernivtsi on the basis of all available literature records for the period of 1874-1986(NOWICKI 1874, R 05 CA 1930, 1935, 1936a, 1936b, 1937, 1938, LegoTAI 1964, ChumAK & PiCHKA 1982, ChUMAK 1986).We included the species recorded by earlier researchers both from Chernivtsi and from settlements such as Tsetsyno, Hot Urban, Klokuchka, Rosha, and Zhuchka, which later became parts of Chernivtsi.NOWICKI (1874) recorded 26 species without mentioning details of collecting methods and habitats.RO^CA (1930-1938) recorded 159 species from Chernivtsi, as the area of the city is currently defined.A description of habitats and collecting methods was not provided, but the author mentioned such habitats as the beech forest on Mt.Tsetsyno, banks of the river Prut, the Botanical Garden, and buildings.RO^CA (1936) provided each species with information on the 'ecological group' to which it belonged, depending on its habitat preferences and other peculiarities: terrestrial forms, plant forms, domestic forms, and hydrophilic forms.Recently, we discussed the distribution of spiders in Chernivtsi according to Ro^ca's publications (FEDORIAK & ZHUKOVETS 2011).LEGOTAI (1964) mentioned two species from Chernivtsi without any details of collecting methods and habitats.CHUMAK & PiCHKA (1982) and CHU-MAK (1986) recorded three spider species collected in greenhouses of the Botanic Garden of Chernivtsi from plants, walls, and the soil surface.
The scientific nomenclature follows PLATNICK (2012).Invalid species names in the literature-derived data are omitted from the analysis (appendix 1).Lephtyphantes collinus (L.Koch, 1872) (RO^CA 1936) is considered to be Megaleptyphantes pseudocoUinus Saaristo, 1997(see SAARISTO 1997).According to the division by KLAUSNITZER (1987), all urban habitats are subdivided into two large groups (buildings and other terrestrial habitats).Thus we analyzed spiders inhabiting buildings (indoor habitats) separately from those inhabiting other (outdoor) habitats.
No publications of earlier researchers contained precise numerical data on abundances of the recorded species.RO^CA (1936, 1937) provided almost every species with information on how often it was observed in Bukovyna: Very often', often', 'not often' or 'rarely'.Therefore we applied only a presence/absence comparison.When discussing our own material, in order to separate the most abundant species in each of the treated spider assemblages, we followed STÖCKER & Bergmann (1977) with dominance classes such as: 31.7-100% -eudominant; 10.1-31.6 % -dominant; 3.2-10.0% -subdominant; 1. 1-3.1 % -recedent; less than 1 % -subrecedent.All calculations in this paper relate to adult specimens.
In total, 107 epigeal species were captured using pitfall traps from different green areas of Chernivtsi.Pardosa lugubris sensu stricto is the most abundant species of the epigeal spider fauna (19.6 % of adults) dominating in city parks, public gardens and other green territories; yet, it is the eudominant species in the industrial enterprises areas sampled.PROKO-PENKO (2000) mentioned R lugubris as a dominant species in five parks of Donetsk (Ukraine).However, it was not abundant in other localities we surveyedonly three specimens were trapped from the Tsetsyno Landscape Conservation Area and from the orchards.The cumulative percentage of Pachygnatha degeeri (Tetragnathidae) was nearly the same as for P lugubris (19.5 %).P degeeri is the only species that dominates the epigeal spider faunas of all the sampled localities, apart from the orchards.Alopecosa pulverulenta (5.1 %) is the subdominant species of the Tsetsyno Landscape Conservation Area (5.7 %), green areas of industrial enterprises (7.2 %), and the orchards (6.0 %).Pardosa agrestis (4.6 %) is distributed very unevenly in the investigated sites: 42.2 % of the adults were trapped from the orchards, 2.8 % -from the Tsetsyno Landscape Conservation Area, and 0.3 % -from the city parks.Some other Lycosidae species were also abundant in the epigeal fauna of Chernivtsi city (in descending cumulative percentage): Pardosa prativaga (4.7 %), P paludicola (3.7 %), Trochosa terricola (3.5 %), 77 ruricola (3.3 %).The cumulative percentages of the other species did not reach 3 % of the adult spider specimens captured by pitfall traps in the sampled localities.Of the representatives of other families some linyphiids, such as Diplostyla concolor (2.6 %) and Diplocephalus picinus (1.8 %), and thomisids, cristatus (2.2 %), were also abundant in the epigeal spider fauna of Chernivtsi.
Nine species were recorded from buildings and 166 from other urban habitats.
Taking into account the information provided by earlier researchers and that resulting from own work, the total spider fauna of Chernivtsi city consists of 260 species from 131 genera and 30 families (appendix 2).Of these, 125 species were mentioned in the literature and occurred in our data.We found 87 species that were not previously reported from Chernivtsi, whereas 48 species of those reported earlier were not found during our survey.Obviously, there were 'exclusive species' that were mentioned only in the literature or occurred only in our data.The share of 'exclusive species' is higher at present (Tab.2); the majority of them belong to Linyphiidae, Lycosidae, Theridiidae, Thomisidae, Gnaphosidae, and Agelenidae.
Differences between the historical records and our data were found in species numbers of various families (Tab.2).In 15 families the number of species increased by 50 %.We noticed the greatest increase in species numbers for Gnaphosidae (4.5-fold), Dictynidae (2-fold), Agelenidae (1.6-fold), and Theridiidae (1.5-fold).Species numbers remained the same in eight families.In comparison with the historical data, we found a smaller number of species of the following three families: Thomisidae, Lycosidae, and Miturgidae.We found no species of Cybaeidae, Sparassidae, Uloboridae, and Zoridae in the area of Chernivtsi, whereas earlier researchers recorded one species from each of these families.

Discussion
R0 §CA (1936) singled out synanthropic species ('domicole') as a separate ecological group of spiders.Overall, he mentioned seven species as synanthropic.Of these, following Ro^ca's terminology, four species were collected 'very often': viz., Pholcus opiliojioides, Ph. phalangioides^ Steatoda bipunctata, and S. castanea\ three were collected 'often': viz., Tegenaria atrica, T. domestica, and Steatoda grossa.We collected all these species in buildings in Chernivtsi.Percentages of all of them, except S. bipunctata^ are higher indoors than in any of the semi-natural habitats such as city parks, lawns.At the same time, RO §CA (1936) regarded Parasteatoda tepidariorum as a species living in trees Tab.2:Total numbers of species of different families collected during 2002-201 1 (our data) and recorded during 1 874-1 986 (historical, literature-derived data) from Chernivtsi.
In general, RO^CA (1936, 1937)  Thus, it seems fair to conclude that the spider assemblages of these areas have undergone some changes.Several reasons are likely to be responsible for such changes: 1. Species habitat change.The spider fauna of urban green areas differs from that of natural and even suburban habitats (KrZYZANOWSKA et al. 1981, ShOCHAT et al. 2004).Regarding our study area, some species were recorded by earlier researchers from the city, whereas we found them only outside the city.For example, we collected Araeoncus humilis, Erigone atra, and Arctosa stigmosa only on the banks of mountain rivers in the Chernivtsi Region (Evtushenko &FED0RIAK 2003)  Other reasons for the changes in the species assemblages of Chernivtsi spider fauna cannot be excluded: e.g., possible differences in the collection methods used by earlier researchers and by ourselves, or collections that were not taken from comparable sites.

Conclusions
Spiders are shown to be a species-rich group in urban habitats of Chernivtsi city (212 spider species belonging to 114 genera and 26 families were found during [2002][2003][2004][2005][2006][2007][2008][2009][2010][2011].This suggests the necessity of surveying urban habitats while estimating spider biodiversity of different regions.Pardosa lugubris and Pachygnatha degeeri were the most abundant species of the epigeal spider fauna, Enoplognatha ovata of trees, and Pholcus phalangioides of the synanthropic spider fauna. Differences in spider species composition between the data recorded in 1874-1986 and our own (2002-2011) may reflect changes in the spider fauna of Chernivtsi city as a result of the combination of several processes, namely: species habitat change, introduction of alien species and description of new species unknown in the late 19th -early 20th centuries.