© Entomologica Fennica. 1 June 2018

Spider assemblages on tree trunks in primeval deciduous forests of the Bia³owie¿a National Park in eastern Poland

Marzena Stañska, Tomasz Stañski & Joanna Hawryluk

Stañska, M., Stañski, T. & Hawryluk, J. 2018: Spider assemblages ontree trunks inprimeval deciduous forests of the Bia³owie¿a NationalPark ineasternPoland. — Entomol. Fennica 29: 75–85. We analysed spider assemblages of tree trunks in an oak-lime-hornbeam forest, anash-alder riparianforest andanalder carr inthe primeval standsof the Bia³o - wie¿a National Park. Spiders were collected from June 1998 to October 2000 us- ing bark traps. A total of 2,182 spider individuals, belonging to 43 species and 14 families was collected. The forest types differed in the spider abundance and spe- cies richness. The differences probably resulted from different tree species and different environmental conditions in the forest types. The most numerous spe- cies in oak-lime-hornbeam forest and in alder carr was Amaurobius fenestralis, whereas Anyphaena accentuata was the most abundant species in ash-alder ri- parianforest. Four species ( Amaurobius fenestralis, Anyphaena accentuata, Segestria senoculata and Neriene montana) were collected ineach month (March–October), whereas most species were recorded sporadically or insome periods. M. Stañska & T. Stañski, Siedlce University of Natural Sciences and Humanities, Faculty of Natural Sciences, Department of Zoology, ul. B. Prusa 12, 08-110 Siedlce, Poland; E-mails: [email protected], tomasz.stanski@uph. edu.pl J. Hawryluk, ul. Walecznych 3/22, 08-300 Soko³ów Podlaski, Poland; E-mail: [email protected] Received 9 May 2017, accepted 10 October 2017

1. Introduction tat for invertebrates, the bark mainly constitutes the trunk features. The bark differs among tree Trees as large complex structures constitute an species and its structure determines physiological important habitat for many groups of inverte- properties (e.g. thermal conditions) and conse- brates (Nicolai 1986, Koponen et al. 1997, Floren quently affects bark-dwelling arthropods (Nico- 2008, Sebek et al. 2016). They provide a variety lai 1986, 1989, 1995). of unique microhabitats (i.e. foliage, branches, Bark-dwelling arthropod communities are trunks, dead parts of wood, crevices and cavities), very diversified and spiders are one of the domi- diversified interms of structure, food availability nant groups among them (Nicolai 1989, 1993, and microclimatic conditions (Prinzing 2005, Koponen et al. 1997, Koponen 2004). Szinetár Michel & Winter 2009, Regnery et al. 2013, and Horváth (2005) informed about 298 spider Wardhaugh et al. 2013). One of the most distinc- species from Europe intheir review of publica - tive microhabitats of a tree is its trunk. As a habi- tions on tree trunk spiders. Blick (2011) reported 76 Stañska et al. • ENTOMOL. FENNICA Vol. 29 a total of 334 spider species recorded onbark nistic and ecological research in this area (Kar- from Germany, i.e. one third of the spider fauna in piñski 1956, £êgowski 2001, Starêga & Kupry- this country. This seems impressive but most of janowicz 2001, Stañska 2007, Stañska et al. the species are rather facultative trunk-dwellers 2016), noresearch has yet beenpublished onspi - or accidental visitors (Wunderlich 1982, Horváth der assemblages ontree trunks. & Szinetár 2002, Szinetár & Horváth 2005). De- The primary objectives of our study were: 1) spite the richness of the spider fauna inhabiting to determine the species diversity of spider as- tree trunks, it is not a frequent subject of research semblages ontree trunksinalder carr, ash-alder compared to other habitats settled by spiders. Ac- riparian forest and oak-lime-hornbeam forest, 2) cording to Blick (2011), the knowledge about the to compare the number of spider individuals and tree trunk fauna in forests of Central Europe is at number of spider species between the three ana- the level of 5% compared to the epigeal fauna. lysed forest types and 3) to assess how these vari- A considerable part of the studies in Europe ables change in time from month to month during has beenconductedinHungary(e.g. Bogya et al. the sampling period. 1999, Horváth & Szinetár 2002, Horváth et al. 2005), but some of them also in Finland (Kopo- nen et al. 1997, Koponen 2008,), Germany (Blick 2. Materials and methods 2011) and the Czech Republic (Machaè & Tuf 2016). Many of the studies devoted to spider as- 2.1. Study area semblages on tree trunks concern habitats created by manor subjected to humanimpact, like or- The study was conducted in the Bia³owie¿a Na- chards (Koœliñska 1967, Pekár 1999, Korenko & tional Park (BNP), which is the best-preserved Pekár 2010), planted trees or plantations of trees part of Bia³owie¿a Forest, a large forest complex (Horváth & Szinetár 1998, Horváth et al. 2004) (1,500 km2) situated onthe border betweenPo- and urban areas (Horváth & Szinetár 2002, land and Belarus. The major part of BNP, pro- Machaè & Tuf 2016). Although there have been tected since 1921, has never been logged and pos- studies from natural areas (Weiss 1995, Blick sesses many characteristics of primeval forest, 2011), there are no publications (to our knowl- like multi-storey, mixed-species and uneven- edge) describing the spider fauna of tree trunks in aged tree stands with a large amount of dead forests preserved in primeval conditions, like wood (Tomia³ojæ 1991, Bobiec 2002). those inBia³owie¿a Forest, easternPoland.Ad - Our study plots, rectangles of about 40 × 20 m mittedly, there are some studies conducted in insize, were located inthree primeval deciduous Bia³owie¿a Forest oncanopyspiders, but their forest stands: oak-lime-hornbeam forest (Tilio- scope covered not only trunks but also the whole Carpinetum), ash-alder riparianforest ( Circaeo- tree crowns and they were conducted in managed Alnetum) and alder carr (Carici elongatae- forest stands (Otto & Floren 2007, Mupepele et Alnetum) (Fig. 1). The first type of forest stands, al. 2014). the oak-lime-hornbeam forest, covers the largest Bia³owie¿a Forest, the largest and best-pre- area of BNP and is the most diverse in the terms of served natural forest complex in the European structure, with many tree species. Lime (Tilia Lowland, is a refuge for many rare or threatened cordata Mill.), hornbeam (Carpinus betulus L.), plant and animal species (Gutowski & Jaro- Norway spruce (Picea abies (L.) H. Karst), szewicz 2004, Oko³ów et al. 2009). The primeval pedunculate oak (Quercus robur L.), ash (Fraxi- forest stands protected in the Bia³owie¿a National nus excelsior L.) and elms (Ulmus spp.) are the Park are distinguished from other European tem- most numerous in this forest type. perate forests by many features (e.g. diverse fo- Our plot was located inthe poorer type of the rest communities, multi-storey profiles of forest oak-lime-hornbeam forest, Tilio-Carpinetum ca- stands, very high trees, large amounts of dead lamagrostietosum, which is characterised by wood) and should be treated as a model of prime- poor forest-floor vegetation and the dominance of val conditions (Tomia³ojæ 1991, Weso³owski hornbeam, oak and spruce. The second plot was 2007). While spiders have beena focus of fau - located inthe ash-alder riparianforest, which is a ENTOMOL. FENNICA Vol. 29 • Spiders on tree trunks in primeval forests 77

Fig. 1. Location of the study plots in the Bia³owie¿a National Park in eastern Poland, each plot representing a different forest type: Ac –alder carr; Olh – oak-lime-hornbeam fo- rest; Rf –ash-alder ri - parian forest. typical plant community growing along the wa- 2.2. Spider samples and statistical analysis tercourses. It consisted of black alder (Alnus glutinosa Gaertn.) and ash, with some admixture Spiders were collected from June 1998 to Octo- of Norway spruce. The vegetationof the forest ber 2000 onthe three plots located each ina dif - floor inthe ash-alder riparianforest was the most ferent type of deciduous forest stand. Samples luxuriant among the analysed plots. The third plot were collected once a month (excluding Novem- was located inalder carr, which also occupies ber, December, January and February) from marshy, fertile habitats but its existence is deter- trunk traps made of 25 cm wide corrugated card- mined by a permanently high water level without board, which were located at 1.5 m above the outflow. This forest type is characterised by a ground on tree trunks. We placed 5 traps, in a dis- well-developed hummock-hollow structure in tance of 7–10 m from each other, in each forest the forest floor. Trees (the most commonbeing type onlivingtrees of a similar diameter selected black alders, ashes and Norway spruces) grow in from the dominant species within each stand. In clumps onthe hummocks, while the hollows the case of alder carr, those were three black al- (with water present for a considerable part of the ders andtwo spruces, inthe ash-alder riparianfo - year) are dominated by marshland plant species rest two black alders, two ashes and one spruce, (Pawlaczyk 2009). and in the oak-lime-hornbeam forest one lime, 78 Stañska et al. • ENTOMOL. FENNICA Vol. 29

Table 1. Spider species collected on tree trunks in deciduous forest stands of the Bia³owie¿a National Park (spi- der families and species in alphabetical order). In statistical analyses, only adult specimens identified to species level were included. Roman letters in last two columns mean months in which spiders were recorded. Abbrevia- tions: Ac –alder carr, Olh –oak-lime-hornbeam forest, Rf –ash-alder riparian fore st, ad –adult spider individu - als, juv –juvenile spider individuals.

Ac Olh Rf Months

ad juv ad juv ad juv ad juv

Agelenidae Coelotes atropos 2 2 25 6 2 V–X VI, VII (Walckenaer, 1830) Amaurobiidae Amaurobius fenestralis 62 123 124 256 2 3 III–X III, V–X (Ström, 1768) Anyphaenidae Anyphaena accentuata 6 98 8 102 12 53 V,VI,VIII,X III,IV,VIII–X (Walckenaer, 1802) Araneidae Araneus diadematus 1X Clerck, 1757 Cyclosa conica 1 VIII (Pallas, 1772) Leviellus stroemi 4 III, VIII–X (Thorell, 1870) Nuctenea umbratica 1X (Clerck, 1757) Clubionidae Clubiona lutescens 8 4 2 3 VI–X VIII Westring, 1851 Clubiona pallidula 3 1 1 V, IX,X (Clerck, 1757) Clubiona phragmitis 1IX C. L. Koch, 1843 Clubiona stagnatilis 1 4 III,IV,X Kulczyñski, 1897 Clubiona subsultans 2 12 3 IX,X Thorell, 1875 Dictynidae Lathys humilis 1 VII (Blackwall, 1855) Lathys stigmatisata 1VI (Menge, 1869) Gnaphosidae Haplodrassus cognatus 1 2 4 V,VI,VIII,X (Westring, 1861) Haplodrassus signifier 1 III (C. L. Koch, 1839) Linyphiidae Agyneta conigera 1 VIII (O. P. Cambridge, 1863) Agyneta innotabilis 1 1 V,VII (O. P. Cambridge, 1863) Drapetisca socialis 25 13 8 12 14 10 IV,VII–X VI–VIII (Sundevall, 1833) Entelecara erythropus 1V (Westring, 1851) Helophora insignis 1 VIII (Westring, 1851) ENTOMOL. FENNICA Vol. 29 • Spiders on tree trunks in primeval forests 79

Ac Olh Rf Months

ad juv ad juv ad juv ad juv

Labulla thoracica 3936713VIII–X VI–VIII (Wider, 1834) Lepthyphantes minutus 20 7 4 VIII–X (Blackwall, 1833) Lophomma punctatum 1 1 III,X (Blackwall, 1841) Moebelia penicillata 1 III (Westring, 1851) Neriene clathrata 1VI (Sundevall, 1830) Neriene montana 18 70 3 17 V–VII III,IV, VI–X (Clerck, 1757) Neriene peltata 1VI (Wider, 1834) Pityohyphantes phrygianus 1 III (C. L. Koch, 1836) Porrhomma pygmaeum 10 III–V, X (Blackwall, 1834) Lycosidae Piratula hygrophila 2VI (Thorell, 1872) Salticidae Pseudicius encarpatus 1V (Walckenaer, 1802) Segestriidae Segestria senoculata 15 76 6 33 2 24 III–X III–X (Linnaeus, 1758) Tetragnathidae Metellina merianae 1IX (Scopoli, 1763) Metellina segmentata 1IX (Clerck, 1757) Pachygnatha clercki 6 1 III,IV X Sundevall, 1823 Theridiidae Enoplognatha ovata 11VI (Clerck, 1757) Platnickina tincta 2 VII,X (Walckenaer, 1802) Steatoda bipunctata 9 18 7 14 4 7 IV–X V–X (Linnaeus, 1758) Theridion mystaceum 7 5 11 V–VII L. Koch, 1870 Theridion varians 1V Hahn, 1833 Thomisidae Diaea dorsata 15 41 1 12 X III, IX,X (Fabricius, 1777) Ozyptila praticola 1V (C. L. Koch, 1837)

Total no. of individuals 208 431 218 471 89 139 Total no. of species 26 23 27 Total no. of exclusive sp. 9 6 9 80 Stañska et al. • ENTOMOL. FENNICA Vol. 29 silver birch Betula pendula and spruce and two Table 2. Results of the GLM analysis assessing asso- hornbeams. The material of each month from ciation of month, forest type (alder carr, ash-alder ri- each plot was combined as one sample, irrespec- parian forest, oak-lime-hornbeam forest) and year with tive of tree species, because of the low abundance the number of collected spider individuals. of spiders on the examined tree trunks. This yielded intotal 19 samples from each plot, i.e. fo - Variable df F p rest type. Month 7 16.80 <0.001 Some spider species are identifiable only as Forest type 2 20.75 <0.001 adults, others are also easy to identify as juve- Year 2 7.64 0.004 niles. Thus, including into analyses all specimens Month × Forest type 14 3.49 0.007 identified to the species level may cause a bias Month × Year 9 2.32 0.061 Forest type × Year 4 2.42 0.086 (overrepresentation of the easy identifiable spe- Error 18 cies). To avoid this problem, we included into all our statistics, including the Shannon index, only adult specimens identified to the species level. planatory variable. Statistical analyses were con- Spider nomenclature is used according to the ducted using the STATISTICA 12.0 program World Spider Catalog (2017). (StatSoft Inc. 2015). The results with p <0.05 Spider species diversity was calculated using were considered statistically significant. the Shannon diversity index:

H’=–S p ln p (1) 3.Results i i where p is the proportion of individuals belong- A total of 2,182 spider individuals belonging to i ing to species i. 14 families were collected during our study: 853 To assess associations of the numbers of col- inalder carr, 888 inoak-lime-hornbeamforest lected spider individuals and species with the fo- and441 inash-alder riparianforest, but we identi- rest types and sampling periods, the General lin- fied to the species level 639, 689, and 228 speci- ear models (GLM) were used (Miller & Haden mens, respectively. Among the spiders identified 2006). The “forest type” (alder carr, ash-alder ri- to the species level, the adult individuals were: parianforest, oak-lime-hornbeamforest) 208 inalder carr, 218 inoak-lime-hornbeamfo- “month” (eight months from March to October) rest and89 inash-alder riparianforest (Table 1). and “year” (three years of study) were treated as Altogether, we found 43 spider species (three fixed categorical explanatory variables. Both of them were identified only as juveniles) but models (i.e. for the number of individuals and the only 14 species were common to the three ana- number of species) included also interactions be- lysed forest types. We found 26 species in alder tween the above mentioned variables, except the carr (including 9 species recorded exclusively one among all the three fixed explanatory vari- there), 23 inoak-lime-hornbeamforest (6 exclu - ables because of the lack of replicates, i.e. there is sive species) and27 inash-alder riparianforest (9 only one sample from each forest type of each exclusive species). Taking into account only month and year. Moreover, in the case of GLM adult specimens, we found 23 species in alder assessing the associations of the variables with carr, 21 in oak-lime-hornbeam forest and 27 in the number of spider species we included in the ash-alder riparianforest (Table 1). analysis log-transformed “number of individu- The most numerous species in the oak-lime- als” as a continuous explanatory variable, in or- hornbeam forest as well as in the alder carr was der to assess whether possible differences in the Amaurobius fenestralis, whereas Anyphaena number of species can be explained by differ- accentuata was the most abundant species in the ences in the numbers of collected individuals. If ash-alder riparian forest. However, taking into GLM revealed a significant effect of a given vari- consideration only adult specimens changed the able, Tukey’s post hoc test was used to evaluate most numerous species inash-alder riparianfo - the differences between the levels of the fixed ex- rest as Drapetisca socialis. Of the 43 species re- ENTOMOL. FENNICA Vol. 29 • Spiders on tree trunks in primeval forests 81

Fig. 2. Least squares means (± SE) (from the statistical model of Table 3) of the numbers of spider individuals collected during the study months in the three forest types in the Bia³owie¿a National Park. a: months in oak-lime-hornbeam forest, which differ from the month indicated by letter b (Tukey’s post hoc test, p = 0.029), but not with each other. c and d: months that differ from each other in alder carr (Tukey’s post hoc test, p = 0.043). Months without let- ters do not differ from other months.

Fig. 3. The relationship between log- transformed number of individuals and number of spider species col- lected in the Bia³owie¿a National Park. corded on tree trunks, only four (A. fenestralis, A. interaction between month and forest type (Table accentuata, Segestria senoculata and Neriene 2). Onaverage, we foundtwo times less spider in - montana) were collected in each analysed month. dividuals inonesample inthe ash-alder riparian Most of the species were recorded insmall num - forest (least squares mean4.5 ± 1.27 SE) com - bers (one or two specimens) or even if they were pared to the alder carr (10.8 ± 1.27) and oak-lime- collected in larger numbers, they were found only hornbeam forest (11.3 ± 1.27) and the differences ina few months(Table 1). betweenthe first andthe two latter habitats were The highest species diversity, calculated for statistically significant (Tukey post hoc test, p < the whole study period, was recorded inash-alder 0.001). The most spider individuals we caught in riparianforest ( H’ = 2.87), lower inalder carr ( H’ the second year of the study (least squares mean = 2.45) and the lowest in oak-lime-hornbeam fo- 11.8 ± 1.36 SE), less inthe first year (7.4 ± 1.53) rest (H’ = 1.75). and the least in the third year (7.5 ± 1.09). The dif- The number of spider individuals collected ferences between the first and the second year and during our study depended on the sampling between the second and the third year were statis- month, year and the forest type, but not straight- tically significant (Tukey post hoc test, p = forwardly so, because there was also a significant 0.016). Generally, the largest number of adult 82 Stañska et al. • ENTOMOL. FENNICA Vol. 29

Table 3. Results of the GLM analysis assessing asso- ders collected on the tree trunks. We identified 43 ciation of number of individuals, month, forest type (al- spider species inthree analysed forest types but der carr, ash-alder riparian forest, oak-lime-hornbeam most of them were collected occasionally. Some forest) and year with the number of collected spider of the species (e.g. Haplodrassus signifer, Pity- species. ohyphantes phrygianus, Lophomma punctatum) were found only in March when winter still pre- Variable df F p vails in the Bia³owie¿a National Park and/or in Number of individuals 1 99.70 <0.001 October when winter was approaching, which Month 7 0.72 0.657 shows that tree trunks serve these species only as Forest type 2 4.74 0.023 a wintering place (Hänggi et al. 1995). Year 2 0.38 0.692 Other species, eventhough recorded onthe Month × Forest type 14 0.83 0.614 tree trunks in several analysed months, were col- Month × Year 9 1.27 0.323 Forest type × Year 4 1.02 0.424 lected insmall numbers (e.g. Clubiona lutescens, Error 17 Neriene peltata). This shows that tree trunks serve them as temporary or accidental habitats where they can find prey or shelter (Szinetár & specimens per sample was collected in Septem- Horváth 2005). ber and the smallest one in March. However, tak- Finally, four species were collected regularly ing into consideration forest types, the most adult in large numbers during the whole trapping peri- specimens in alder carr and oak-lime-hornbeam od, i.e. ineach monthfrom March to October: A. forest were collected inSeptember whereas in fenestralis, A. accentuata, S. senoculata, and N. ash-alder riparianforest inMay. The smallest montana. This clearly shows that tree trunks are a number of spider specimens in alder carr was commonhabitat for these species, eventhough foundinJuly whereas inMarch inthe two other they do not live exclusively on the bark (Wun- forests (Fig. 2). derlich 1982). Other authors also reported the The number of collected spider species de- first three species as abundant trunk-dwellers as pended, as expected, positively on the number of Horváth and Szinetár (1998) found A. fenestralis, spider individuals, i.e. the sample size (Fig. 3), A. accentuata, and S. senoculata the most fre- and forest type (Table 3). The number of spider quent bark-dwelling spiders on black pine (Pinus species per sample was the highest inalder carr nigra). Blick (2011) listed A. fenestralis and A. (least squares mean4.2 ± 0.31 SE), lower inthe accentuata among the twenty most abundant ash-alder riparianforest (3.9 ± 0.35) andthe low - bark spider species inGermany. Intheir study est inoak-lime-hornbeamforest (3.0 ± 0.30). The conducted in the Czech Republic, Machaè and differences between the first and the two latter Tuf (2016) found A. accentuata to be one of the habitats were statistically significant (Tukey post most abundant spider species, both in a town and hoc test, p = 0.022). in the surrounding floodplain forest. The fourth abundant species in our study, N. montana,was 4. Discussion recorded by some authors onthe trunksbut in small numbers (Koponen 2008, Machaè & Tuf Ingeneral, spider species collected ontree trunks 2016). canbe divided intotwo maingroups: spiders liv - Besides the above-mentioned species, we ing constantly on the tree trunks (on the bark or found other typical tree bark spiders: Nuctenea under the bark) and spiders for which trunks are a umbratica, Haplodrassus cognatus, Agyneta in- temporary habitat (Wunderlich 1982, Horváth & notabilis, D. socialis, Moebelia penicillata, Szinetár 2002). Spiders from the first group can Pseudicius encarpatus, Steatoda bipunctata and be found on the tree trunks during the whole year, Theridion mystaceum, although some of them whereas those from the second group live also in were not numerous. Szinetár and Horváth (2005) other habitats besides trunks and visit the bark categorized them as exclusive bark-dwelling spe- sporadically or for overwintering. Based on our cies or facultative bark-dwellers with a close rela- research, we canmake the same divisionof spi - tionship with tree trunks. ENTOMOL. FENNICA Vol. 29 • Spiders on tree trunks in primeval forests 83

Inour research, we collected a few species search on spider communities in forest canopies, that have not been mentioned in the literature de- Korenko et al. (2011) found that spider species voted to the bark-dwelling spiders (e.g. Szinetár richness and abundance were higher on conifer- & Horváth 2005, Koponen 2008, Machaè & Tuf ous thandeciduous trees. They also founddiffer - 2016): Clubiona phragmitis, Lathys stigmatisata, ences across deciduous tree species, as both the H. signifer, Helophora insignis, L. punctatum, abundance and species richness were signifi- Pachygnatha clercki and Metellina segmentata. cantlyhigher onblack alder thanontwo oak spe - Clubiona phragmitis and M. segmentata are spe- cies. cies living in the herb and bush layer and the rest The variationinspider assemblages livingon are typical ground dwelling spiders. All these spi- trunks of different tree species can be explained, ders seem to be accidental on tree trunks, because among other things, by differences in the bark other microhabitats are the typical for them structure. Trunks with structurally more complex (Hänggi et al. 1995). bark are more attractive for spiders thantrunks It is worth to mentionthatineach type of in - with smooth bark (Curtis & Morton1974, Nicolai vestigated forest we caught Coelotes atropos,a 1986). Prinzing (2001, 2005) showed that the species that seems to be commoninthe primeval distributionof bark-dwellingarthropods is sig - forests in the ground layer and under the bark nificantly modified by microclimatic conditions (Sechterová 1992, Stañska et al. 2016). (e.g. temperature, humidity) prevailing on trunks Our study revealed differences in spider and arthropods are able to respond to the fluctua- abundance and number of species among the tions in these conditions by, for example, com- three analysed types of forests. On average, pensatoryredistributionwithinthe mosaic pat- samples from the alder carr and oak-lime horn- ternof microhabitats ontrunks. beam forest contained twice as many spider indi- The next reason for the differences in spider viduals as the samples from the ash-alder riparian assemblages betweenthe three forest types may forest. In spite of the lowest number of individu- result from differences in general environmental als inthe ash-alder riparianforest, the highest parameters (not only those directly related to species diversity (H’ calculated for the whole trunks) and the habitat structure within particular study period) was found there, and the lowest forest types. Many studies have shown that arbo- species diversity and total number of species real spider communities are shaped by, among were inthe oak-lime-hornbeamforest. Moreover, other things, humidity, ground vegetation, forest there were also differences in the species compo- floor structure, the presence of woody debris, sition and abundance of particular spider species canopy openness and the type of litter, which betweenthe forest types. Of all the collected spi - partly result from the tree species growing in par- der species, only one third was common to the ticular forests (Ziesche & Roth 2008, Castro & three types of forest. The most abundant species Wise 2009, Košuliè et al. 2016, Stañska et al. in the oak-lime-hornbeam forest and in the alder 2016). The three types of forests analysed in our carr, i.e. A. fenestralis, accounted for only a few study differed considerably in a number of these individualsinthe ash-alder riparianforest (Table factors. For example, both the alder carr and the 1). In our opinion, one of the likely reasons of riparianforest were more humid thanthe oak- such a result is the placement of the traps on the lime-hornbeam forest. Moreover, the vegetation different tree species in the three analysed forests of the forest floor was poorer inthe oak-lime- (unfortunately, tree species could not be included hornbeam forest and luxuriant in the ash-alder ri- inthe analysis because the material was com - parianforest, which probably affected the num - bined from all the traps of each plot). The study of ber of collected spider individuals. The hum- Mupepele et al. (2014), using insecticide fogging mock-hollow structure of the alder carr and water in the canopy of the managed part of Bia³owie¿a stagnating between trees over a long period of the Forest and three different forests, showed that the year probably increase the importance of trunks spider communities were tree-species specific. both as a place of living and as a refuge allowing This phenomenon was observed for black alder, spiders to wait for the end of the flooding period. hornbeam, spruce and Scots pine. In their re- Our study revealed that the number of spider 84 Stañska et al. • ENTOMOL. FENNICA Vol. 29 individuals changed among months and years Curtis, D. J. & Morton, E. 1974: Notes on spiders from tree during the sampling period. The reasons may be trunks of different bark texture; with indices of diversi- ty and overlap. — Bulletin of the British Arachnologi- partially the same as inthe case of differencesbe - cal Society 3: 1–5. tween the forest types, but with changes among Floren, A. 2008: Abundance and ordinal composition of the seasons of the year. Such factors, as vegeta- arboreal arthropod communities of various trees in old tionstructure, insolationorhumidity changeover primary and managed forests. — In: Floren, A. & the seasonandcanvary from year to year. This Schmidl, J. (eds), Canopy arthropod research in Euro- may cause that during some periods of the year pe: 279–298. Bioform Entomology, Nuremberg. 576 pp. tree trunks may become an attractive habitat for Gutowski, J. M. & Jaroszewicz, B. 2004: Puszcza Bia³owi- spiders, where they canfindprey or shelters from eska jako ostoja europejskiej fauny owadów. Bia³owi- unfavorable environmental conditions. Changes e¿a Primeval Forest as a refuge of the Europeanento - inthe use of tree trunksmay also result from the mofauna. — Wiadomoœci entomologiczne 23: 67–87. phenology of particular spider species. [inPolish with Englishabstract.] Hänggi, A., Stöckli, E. & Nentwig, W. 1995: Habitats of In conclusion, the spider fauna of tree trunks Central European spiders. — Centre suisse de carto- differed betweenthe three analysed forest types graphie de la faune (CSCF) Neuchâtel, 460 pp. in the number of individuals and the species com- Horváth, R. & Szinetár, C. 1998: Study of the bark-dwel- position. In our opinion, the differences probably ling spiders (Araneae) on black pine (Pinus nigra)I. result from different tree species on which the — Miscellanea Zoologica Hungarica 12: 77–83. traps were located and from different environ- Horváth, R. & Szinetár, C. 2002: Ecofaunistical study of bark-dwelling spiders (Araneae) on black pine (Pinus mental conditions in the particular forest types. nigra) inurbanandforest habitats. — Acta Biologica Of the 43 recorded species, only some were regu- Debrecina 24: 87–101. larly collected during the whole study period (A. Horváth, R., Lengyel, S., Szinetár, C. & Honti, S. 2004: fenestralis, A. accentuata, S. senoculata,andN. The effect of expositiontime andtemperature onspi- montana), whereas for most species tree trunks ders (Araneae) overwintering on the bark of black pine were temporary or accidental habitats. (Pinus nigra). — In: Samu, F. & Szinetár, C. (eds), Eu- ropean Arachnology 2002: proceedings of the 20th Eu- ropean Colloquium of Arachnology: 95–102. Plant Acknowledgements. We would like to thank the authorities Protection Institute and Berzsenyi College, Budapest. of the Bia³owie¿a National Park for their kind help during 356 pp. conducting our research. We also would like to thank two Horváth, R., Lengyel, S., Szinetár, C. & Jakab, L. 2005: anonymous reviewers for their suggestions and comments The effect of prey availability onspider assemblages that were very helpful in improving the manuscript. The re- onEuropeanblack pine( Pinus nigra) bark: spatial pat- sults of the research carried out under the research theme terns and guild structure. — Canadian Journal of Zoo- No. 222/05/S were financed from the science grant granted logy 83: 324–335. by the Ministry of Science and Higher Education and by Karpiñski, J. J. 1956: Paj¹ki (Araneida) w Biocenozie State Committee for Scientific Research (grant 6P04- Bia³owieskiego Parku Narodowego. — Roczniki G01417). Nauk Leœnych 14: 29–47. [In Polish.] Koponen, S. 2004: Arthropods from high oak branches – References comparisonof two trap types, with a special reference to spiders. — Latvijas Entomologs 41: 71–75. Blick, T. 2011: Abundant and rare spiders on tree trunks in Koponen, S. 2008: Spiders from groves in the southwes- German forests (Arachnida, Araneae). — Arachnolo- tern archipelago of Finland (Araneae). — Revista Ibé- gische Mitteilungen 40: 5–14. rica de Aracnología 15: 97–104. Bobiec, A. 2002: Living stands and dead wood in the Koponen, S., Rinne, V. & Clayhills, T. 1997: Arthropods Bia³owie¿a forest: suggestions for restoration mana- on oak branches in SW Finland, collected by a new gement. — Forest Ecology and Management 165: trap type. — Entomologica Fennica 8: 177–183. 125–140. Korenko, S. & Pekár, S. 2010: Is there intraguild predation Bogya, S., Szinetár, C. & Markó, V. 1999: Species compo- between winter-active spiders (Araneae) on apple tree sitionof spider (Araneae)assemblages inapple and bark? — Biological Control 54: 206–212. pear orchards inthe CarpathianBasin.— Acta Phyto - Korenko, S., Kula, E., Šimon, V., Michalková, V. & Pekár, pathologica et Entomologica Hungarica 34: 99–121. S. 2011: Are arboreal spiders associated with particu- Castro, A. & Wise, D. H. 2009: Influence of fine woody lar tree canopies? — Nort-Western Journal of Zoology debris on spider diversity and community structure in 7: 261–269. forest leaf litter. — Biodiversity Conservation 18: Koœliñska, M. 1967: Badania nad faun¹ zimuj¹c¹ pod kor¹ 3705–3731. i w korze jab³oni. Czêœæ II. Badania nad pajêczakami ENTOMOL. FENNICA Vol. 29 • Spiders on tree trunks in primeval forests 85

(Arachnida) — Polskie Pismo Entomologiczne, 37: Which factors influence the occurrence and density of 587–602. [InPolish.] tree microhabitats inMediterraneanoakforests? — Košuliè, O., Michalko, R. & Hula, V. 2016: Impact of ca- Forest Ecology and Management 295: 118–125. nopy openness on spider communities: implications Sechterová, E. 1992: Onthe biology of species of the ge - for conservation management of formerly coppiced nus Coelotes (Araneae, Agelenidae) in central Euro- oak forests. — PLoS ONE 11(2): e0148585. doi:10. pean mountains. — Acta Entomologica Bohemoslo- 1371/journal.pone.0148585. vaca 89: 337—349. £êgowski, D. 2001: Waloryzacja lasów Puszczy Bia³owi- Sebek, P., Vodka, S., Bogusch, P., Pech, P., Tropek, R., eskiej metod¹ zooindykacyjn¹ na podstawie paj¹ków Weiss, M., Zimova, K. & Cizek, L. 2016: Open-grown (Aranei). — In: Szujecki, A. (ed.), Próba szacunkowej trees as key habitats for arthropods intemperate wood - waloryzacji lasów Puszczy Bia³owieskiej metod¹ zo- lands: The diversity, composition, and conservation oindykacyjn¹: 207–233. Wydawnictwo SGGW, value of associated communities. — Forest Ecology Warszawa. 419 pp. [InPolish.] and Management 380: 172–181. Machaè, O. & Tuf, I. H. 2016: Spiders and harvestmen on Stañska, M. 2007: Rare and threatened spider species tree trunks obtained by three sampling methods. — (Araneae)inselected types of deciduous forests inthe Arachnologische Mitteilungen 51: 67–72. Bia³owie¿a Forest. — Nature Conservation 64: 13–29. Michel, A. K. & Winter, S. 2009: Tree microhabitat struc- Stañska, M., Stañski, T., G³adzka, A. & Bartos, M. 2016: tures as indicators of biodiversity in Douglas-fir fo- Spider assemblages of hummocks and hollows in a rests of different stand ages and management histories primeval alder carr inthe Bia³owie¿a NationalPark – inthe Pacific Northwest, U.S.A. — Forest Ecology effect of vegetationstructure andsoil humidity. — Po - and Management 257: 1453–1464. lish Journal of Ecology 64: 564–577. Miller, J. & Haden, P. 2006: Statistical Analysis with the Starêga, W. & Kupryjanowicz, J. 2001: Subclassis (pod- General Linear Model. Creative Commons Attribu- gromada): Araneae – paj¹ki. — In: Gutowski, J. M. & tion. 259 pp. Jaroszewicz, B. (eds), Katalog Fauny Puszczy Mupepele, A. C., Müller, T., Dittrich, M. & Floren, A. Bia³owieskiej: 55–63. Instytut Badawczy Leœnictwa, 2014: Are temperate canopy spiders tree-species spe- Warszawa. 404 pp. [InPolish.] cific? — PLoS ONE 9(2): e86571. doi:10.1371/jour- Szinetár, C. & Horváth, R. 2005: A review of spiders on nal.pone.0086571. tree trunks in Europe (Araneae). — In: Deltshev, C. & Nicolai, V. 1986: The bark of trees: thermal properties, mi- Stoev, P. (eds), EuropeanArachnology2005, Acta croclimate and fauna. — Oecologia 69: 148–160. zoologica bulgarica, Suppl. No. 1: 221–257. Institute Nicolai, V. 1989: Thermal properties and fauna on the bark of Zoology and National Museum of Natural History, of trees intwo differentAfricanecosystems. — Oeco- BulgarianAcademy of Sciences,Blagoevgrad. 343 logia 80: 421–430. pp. Nicolai, V. 1993: The arthropod fauna on the bark of deci- Tomia³ojæ, L. 1991: Characteristics of old growth inthe duous and coniferous trees in a mixed forest in the Ita- Bia³owie¿a Forest, Poland. — Natural Areas Journal sca State Park, MN, USA. — Spixiana 16: 61–69. 11: 7–18. Nicolai, V. 1995: The ecological significance of trees’ Wardhaugh, C. W., Edwards, W. & Stork, N. E. 2013: Bo- bark during ecosystem dynamics. — Spixiana 18: dy size variation among invertebrates inhabiting diffe- 187–199. rent canopy microhabitat: flower visitors are smaller. Oko³ów, C., Karaœ, M. & Bo³bot, A. 2009: Bia³owie¿a Na- — Ecological Entomology 38: 101–111. tional Park, know it, understand it, protect it. — Weiss, I. 1995: Spinnen und Weberknechte auf Baum- Bia³owieski Park Narodowy, Bia³owie¿a. 240 pp. stämmen im Nationalpark Bayerischer Wald. — In: Otto, S. & Floren, A. 2007: The spider fauna (Araneae) of Rùžièka, V. (ed.), Proceedings of the 15th European tree canopies in the Bia³owie¿a Forest. — Fragmenta Colloquium of Arachnology: 184–192. Czech Acade- Faunistica 50: 57–70. my of Sciences, Institute of Entomology, Èeské Budì- Pawlaczyk, P. 2009: Forest communities. — In: Oko³ów, jovice. 238 pp. C.,Karaœ,M.&Bo³bot,A.(eds),Bia³owie¿aNational Weso³owski, T. 2007: Primeval conditions – what can we Park. Know it – Understand it – Protect it: 37–58. learnfrom them? — Ibis 149: 64–77. Bia³owieski Park Narodowy, Bia³owie¿a. 240 pp. World Spider Catalog 2017: World Spider Catalog, ver- Pekár, S. 1999: Some observations on overwintering of sion18.0. Natural History Museum Bern.[www docu - spiders (Araneae) in two contrasting orchards in the ment]. URL http://wsc.nmbe.ch. (Site visited on 21 Czech Republic. — Agriculture, Ecosystems and En- April 2017). vironment 73: 205–210. Wunderlich, J. 1982: Mitteleuropäische Spinnen (Arane- Prinzing, A. J. 2001: Use of shifting microclimatic mosaics ae) der Baumrinde. — Zeitschrift für angewandte En- by arthropods on exposed tree trunks. — Annals of the tomologie 94: 9–21. Entomological Society of America 94: 210–218. Ziesche, T. M. & Roth, M. 2008: Influence of environmen- Prinzing, A. 2005: Corticolous arthropods under climatic tal parameters onsmall-scale distributionof soil-dwel - fluctuations: compensation is more important than mi- ling spiders in forests: what makes the difference, tree gration. — Ecography 28: 17–28. species or microhabitat? — Forest Ecology and Mana- Regnery, B., Paillet, Y., Couvet, D. & Kerbiriou, C. 2013: gement 255: 738–752.