Diversity and species composition of beetles in the herb-shrub layer of a large isolated raised bog in Belarus G.G. Sushko Department of Ecology and Environmental Protection, Vitebsk State University P.M. Masherov, Belarus _______________________________________________________________________________________ SUMMARY Temperate zone peat bogs form isolated ecosystems relative to their surroundings. The aim of the work reported was to investigate the species composition and diversity of the field layer beetles of an undisturbed natural bog in Belarus. In total, 99 beetle species belonging to 13 families were sampled along transects, using a sweep-net. A specific complex of Coleoptera species was found. The results showed a low diversity and species richness of beetle assemblages and a high abundance of a small number of species. Among these species, the primary peat bog specialists were Cyphon kongsbergensis Munster, 1924, Cantharis quadripunctata (Müller, 1764), Plateumaris discolor (Herbst, 1795), Aphthona erichsoni (Zetterstedt, 1838) and Altica longicollis (Allard 1860), which are rare in central Europe. Both the abundance and the species richness of Coleoptera were highest in shrub habitat. General linear modelling results (GLM) indicated that vegetation characteristics strongly influenced beetle abundance and species richness in peat bogs, which is interpreted as a measure of heterogeneity. KEY WORDS: assemblages, Coleoptera, peat bog, tyrphobiont, tyrphophilous _______________________________________________________________________________________ INTRODUCTION aquatic-edge habitats (Spitzer & Danks 2006). The vegetation of ombrotrophic mires is isolated from the Today, peat bogs present some of the best examples influence of mineral-rich groundwater and is fed of highly specific and relict habitats (palaeorefugia) almost exclusively by precipitation water. For that and are of great importance for global and reason bog ecosystems are especially sensitive to international species conservation (Joosten & Clarke climate change and also serve as valuable archives of 2002, Spitzer & Danks 2006, Wieder & Vitt 2006). detailed information for reconstructing past The raised bogs of Central Europe, in particular, are environments (Barber et al. 1994, Blackford 2000). island-like ecosystems with very specific For bird species, bogs offer viable breeding environmental conditions and biota. Sphagnum moss habitats and also play a central role as migration and with scattered or clumped ericaceous shrubs wintering sites. Bogs are especially important for the dominate these bogs, their mineralisation level is conservation of rare tyrphobiontic and tyrphophilous low, and their peat growth rate is high (Pidoplichko insects (Bragg & Lindsay 2003). Tyrphobiontic 1961, Geltman 1982, Bragg & Lindsay 2003, insect species are obligatorily restricted to bog Yelovicheva et al. 2008). The conditions strongly habitats (bog dependent) and can be host-specialists influence the structure of their invertebrate and/or host-generalists (Mikkola & Spitzer 1983, communities including their insect inhabitants Spitzer & Danks 2006, Swengel & Swengel 2011). (Spitzer & Danks 2006, Dapkus & Tamutis 2008, Tyrphophilous insect species are generally associated Sushko & Borodin 2009, Sushko & Lukashuk 2011). with bog habitats but are not restricted to these Because 62 % of European mires and peatlands have habitats (facultative bog species). At present the been destroyed due to human activities (Joosten fractions of tyrphobiontic species amongst the insect 1999, Bragg & Lindsay 2003), there is insufficient assemblages of most bogs are quite low. In the past, information on the fauna of pristine bogs in general however, their representation may have been higher and on their insect species in particular. in pristine bogs. When we look at descriptions of the We know from literature that Central European invertebrate fauna of European peatlands from the bogs harbour a unique diversity of cold-adapted first decades of the twentieth century (Dampf 1924, plants and insects, which have survived since the Peus 1928, Skwarra 1929, Roubal 1934) we find that Late Glacial and early Holocene periods. Many bog the authors mentioned a large number of invertebrate inhabitants have specific habitat requirements, such species that appeared to be restricted to peatlands, at as acidic and nutrient-poor conditions, specific cold- least in the southern parts of their geographical adapted or bog-confined food plants, and aquatic or ranges (Peus 1928, Roubal 1934, Spitzer & Jaroš Mires and Peat, Volume 19 (2017), Article 10, 1–14, http://www.mires-and-peat.net/, ISSN 1819-754X © 2017 International Mire Conservation Group and International Peatland Society. DOI: 10.19189/MaP.2017.OMB.266 1 G.G. Sushko BEETLES IN THE HERB-SHRUB LAYER OF A RAISED BOG IN BELARUS 1993, Rampazzi & Dethier 1997). an undisturbed natural peat bog in Belarus. The The Coleoptera (beetles) make up the most second aim is to examine environmental factors diverse order of insects. Cursory examination of their affecting the species richness and abundance of basic structure may do little to suggest why the group beetles in this peatland. Particular emphasis is given should be so successful, yet they have come to to specialised bog species that may be valuable as occupy an amazing variety of habitats. About 75 % biological indicators and are, thus, potential primary of beetle species are phytophagous in both larval and protection targets for peatland management. adult stages, living in or on plants, wood and fungi and playing an important role in the ecosystem (Gillott 2005). METHODS The Coleoptera represent one of the most abundant animal groups in peatlands. They are Study site important members of food webs, providing protein This research was carried out during the period 2010– for species at higher trophic levels (Maavara 1955, 2015 on the 19,984 ha ‘Yelnia’ peat bog in Belarus Spungis 2008, Sushko 2012). Previously, the species (55° 34' N, 27° 55' Е). This is the largest and least richness of beetles was estimated mainly in the anthropically modified bog in the country and is Sphagnum carpet (Främbs et al. 2002, Mossakowski currently protected as a landscape reserve. The et al. 2003, Dapkus & Tamutis 2008), so it was not international conservation status IBA (Important possible to build a full understanding of the Bird Area) was established in 1998 (code BY 002, composition of the beetle fauna in different (sub-) criteria A4, B1, B2) (Kozulin et al. 2005). It could be habitats and different layers of the vegetation. Very claimed that Yelnia is a pristine model for European few papers have been dedicated to the chamebionts bogs. Its centre is about 7 m higher than its periphery and chortobionts (shrub- and herb-dwellers) of peat and the peat layer can be as deep as 8.3 m, but is bogs, and knowledge about beetle species 3.8 m thick on average. It includes more than 100 composition in the shrub and herb layers is lakes (Kozulin et al. 2005, Yelovicheva et al. 2008) consequently sparse. Moreover, information on the (Figures 1 and 2). There is a slope, a summit, and a sub-habitats of beetles (e.g. hummocks, hollows, plateau which is located at the edge of the border lagg) is almost lacking (Peus 1928, Roubal 1934, zone (lagg zone) and is periodically flooded due to its Maavara 1957, Spungis 2008). lower altitude (Figure 3). The water table level shows The present study aims, firstly, to describe the distinct patterns in different habitats. It was found species composition and diversity of shrub-and-herb- that the water table was highest (relative to the layer beetle assemblages (including tyrphophilous ground surface) in the lagg, hollows and lakeshores, species) associated with seven main sub-habitats in and deepest on the dome (Table 1). Figure 1. An oblique aerial photograph of the Yelnia peat bog (photo: I. Borok). Mires and Peat, Volume 19 (2017), Article 10, 1–14, http://www.mires-and-peat.net/, ISSN 1819-754X © 2017 International Mire Conservation Group and International Peatland Society. DOI: 10.19189/MaP.2017.OMB.266 2 G.G. Sushko BEETLES IN THE HERB-SHRUB LAYER OF A RAISED BOG IN BELARUS Vegetation 7) dome (D) (plant association: Eriophorum Vegetation surveys were conducted according to the vaginatum - Calluna vulgaris - Sphagnum fuscum) method of Brown (1954) in seven of the most typical (Figure 3). peat bog habitats (plant association types based on 2 the dominant species in each layer of the vegetation In each habitat three areas of 250 m with canopy): homogeneous vegetation were sampled (21 sites in total) in July 2011. Four vegetation attributes were 1) lagg zone (LZ) at the bog margin (plant recorded in each site, namely: cover (%) of shrubs association: Eriophorum vaginatum - Sphagnum and herbs, the number of species of vascular plants, angustifolium); and the presence of trees (Table 1). Sites were situated more than 50 m from each other. 2) pine bog (PB) on the slope (plant association: Pinus sylvestris - Eriophorum vaginatum/Ledum palustre - Sphagnum magellanicum); Coleoptera survey Coleoptera were sampled with an entomological 3) hollow (HOL) on the slope (plant association: sweep-net (diameter 30 cm) along 50 m transects that Rhynchospora alba - Sphagnum cuspidatum); were 5 m wide (250 m2 per site). Exactly 50 net sweeps were done on each transect, twice a month. 4) hummock (HUM) on the slope (plant association: For statistical analysis, all data from each site were Eriophorum vaginatum - Oxycoccus