Acta Biol. Univ. Daugavp. 14 (2) 2014 ISSN 1407 - 8953 DIVERSITY OF SAPROXYLIC BEETLES (HEXAPODA: COLEOPTERA) IN CLEAR-CUT SITES WITH REMOVED AND RETAINED STUMPS IN CENTRAL LATVIA Inese Kivleniece, Arvīds Barševskis, Sakine Serap Avgin, Astra Zaļuma Kivleniece I., Barševskis A., Avgin S.S., Zaļuma A. 2014. Diversity of saproxylic beetles (Hexapoda: Coleoptera) in clear-cut sites with removed and retained stumps in central Latvia. Acta Biol. Univ. Daugavp., 14 (2): 145 – 157. Saproxylic insects represent an important part of forest biodiversity and have functionally significant role in the forest ecosystems. They are species-rich organisms that depend upon the dead or dying wood or upon the presence of other saproxylic species. In this study we investigated whether stump harvesting affects saproxylic beetle assemblages in the clear-cut of managed forest in Latvia. We used pitfall traps and window traps for sampling beetles in the clear-cut sites with removed and retained stumps. Overall, these two sampling sites shared a similar number of beetle species. However, there were significant differences between two sampling methods with more species from window traps. Saproxylic species were more abundant in site with retained stumps. Key words: saproxylic beetle, stump harvesting, clear-cut, Hylocomiosa, window traps, pitfall traps. Arvīds Barševskis, Inese Kivleniece. Coleopterological Research Center, Institute of Life Sciences and Technology, Daugavpils University, Ilgas, Daugavpils Municipality, LV-5470, Latvia, e-mail: [email protected], [email protected] Sakine Serap Avgin. Kahramanmaraş Sütçü İmam University, Faculty of Education, Division of Science Education, Avşar Campus, 46100 Kahramanmaraş, Turkey, e-mail: serapavgin@ hotmail.com Astra Zaļuma. Forest Sector Competence Center, SIA “MNKC”, Dzerbenes Street 27, Riga, LV-1006, Latvia, e-mail: [email protected] INTRODUCTION a food base for other organisms (Warriner et al. 2004). A radical decline in the abundance of Saproxylic or dead wood inhabiting insects saproxylic insects and threatened species is a comprise a significant proportion of the direct outcome of the large reduction of dead, biodiversity of most forest ecosystems (Jackson decaying wood and old living trees in the forest et al. 2009, Stenbacka et al. 2010). They are landscape by modern forestry and agricultural vitally important in the initial fragmentation and practices (Martikainen et al. 2000, Siitonen 2001, breakdown of dead woody debris and comprise Hjalten et al. 2007). To predict extinction risks 145 Kivleniece I., Barševskis A., Avgin S.S., Zaļuma A. and to evaluate the efficiency of conservation & Gustafsson 2005, Äijälä et al. 2005, Eräjää et efforts, we need to understand the ecology of al. 2010). saproxylic species and to study the dynamics of the habitats and the inhabiting populations. Stumps produce similar amounts of saproxylic species as snags and logs and only some Stumps are homogenous key alternative differences in species composition could be microhabitats for saproxylic organisms in observed (Dahlberg & Stokland 2004, Wikars managed forests (Gibb et al. 2006, Franc et et al. 2005, Abrahamsson & Lindbladh 2006, al. 2007, Lindbladh et al. 2007, Jonsell 2008). Hedgren 2007, Jonsell & Hansson 2011). Globally growing interest for forest biofuels However, contradictory results may be found such as slash (branches and tops) and stumps (Kruys & Jonsson 1999, Franc 2007, Bässler et significantly increases intensity of stump and root al. 2010, Bouget et al. 2012, Brin et al. 2012). harvesting in clear-cuts (Hakkila 2004, Björheden Andersson et al. (2012) found that stump 2006, Walmsley & Godbold 2009). Stump removal had non-significant long-term effect on extraction has also been used as a silvicultural beetle abundance, species richness and species treatment method to control post-harvest root- composition, although several groups of beetles rot fungi in forests (Chapman & Xiao 2000, were strongly affected by characteristics of the Chapman et al. 2004, Cleary et al. 2013) and surrounding forest. Investigations on the effects to improve site preparation for re-growth or re- of stump harvesting on forest biodiversity and on planting of forest. The removal of stumps and possible long-term effects are rare. roots negatively affects fauna and flora that use them as a food sources, platforms, dens, nest sites, Studies on stump harvesting effect on saproxylic habitats or refuges (Davis 1996, Keisker 2000, beetle species in Latvia are lacking. In this study Waldien et al. 2000, Bunnell & Houde 2010). In we investigated differences in the saproxylic Finland, Sweden and the UK stump harvesting beetle assemblages in two clear-cut sites with is performed only during final felling (not during removed and retained stumps. Both sampling thinning) to exclude risk of damaging adjacent sites are characterized by significant ecological trees (Forestry Commission 2009, Swedish differences in vegetation and site conditions. Forest Agency 2009, TAPIO 2010). In Nordic These and other factors may play important region, the stump retention guidelines state that roles in forming the saproxylic beetle fauna of minimum number of retained stumps is 20/ha (50/ both sites. We predicted lower numbers of dead ha on finer-textured soils) (Stupak et al. 2008), wood dwelling species in stumped area than in whereas in the UK about 20-30% of the forest non-stumped site. Two types of traps were used surface should be left undisturbed by stump in this study and capture effectiveness of each removal (Forestry Commission 2009). However, sampling method was established. in practice small pine stumps are retained at the expense of large spruce stumps because spruce stumps are more easily pulled from the ground MATERIALS AND METHODS than pine stumps (Kalliola & Markkila 2004). In Latvia, spruce, birch and aspen stands are more Study site appropriate for stump removal, but pine stands are more protected by technical constraints and Research area, Hylocomiosa forest type, was legislation of environmental protection. The located in central Latvia, in Ogresgals rural main resources for forest fuels are stumps from municipality (N: 56°46’57.8” E: 24°45’18”). The private and national Latvian forests (Lazdāns et selection criteria for forest site were: dominance al. 2008). The effects of increasing forest fuel of Picea abies, high rot incidence (> 50%) and harvesting on the forest ecosystems are poorly weak regeneration of Populus tremula. The understood (Koistinen & Äijälä 2005, Rudolphi chosen forest site which fulfilled these criteria was dominated by P. abies (60% of stand volume) 146 Diversity of saproxylic beetles (Hexapoda: Coleoptera) in clear-cut sites with removed and retained stumps in central Latvia with admixture of Pinus sylvestris and Betula Characterization of vegetation after stump pendula. The forest site was 98 years old with size removal in 2013 3 ha. This site had been felled in autumn 2010. In 2012, clear-cut was divided into two separate O1: shrubs and young trees were cut down, herbs sample plots: plot with removed stumps and plot were mowed down. Stump removal promoted with retained stumps. Each area was 0.5 ha in size formation of furrows and soil outcrops. with buffer zone between them. On one plot (O1) stumps were removed in November 2012 using O2: shrubs and young trees were cut down, caterpillar excavator New Holland E215B with herbs were mowed down. The whole area was stump extractor MCR-500 prototype. On second mounded. plot (O2) stumps were left intact. The collection of beetles was done in 2013. Both sample plots (O1 and O2) were replanted in June 2013 with 2-year-old nursery cultivated Characterization of vegetation before stump bare-root seedlings of P. abies with improved removal in 2012 root system. O1 – plot with removed stumps (Fig. 1). The clear- Insect sampling cut area was covered by naturally regenerated young Betula pendula, Picea abies, Pinus Beetles were sampled using pitfall traps and sylvestris, Populus tremula, Quercus robur and window traps. Window trap consisted of Sorbus aucuparia trees and some shrubs: Corylus transparent Plexiglas sheet (L x W, 60 x 40 cm) avellana, Frangula alnus and Rubus idaeus. attached with a nylon rope to a plastic container The herb species were abundant, dominating (L x W x H, 50 x 20 x 15 cm). Ethylene glycol by Calamagrostis arundinacea, Chamaenerion diluted with water was used as a preservative in angustifolium, Erigeron canadensis, Juncus a collecting container. Window traps were hung effusus, Galeopsis bifida, Impatiens parviflora, between two artificially placed wooden poles Luzula pilosa, Mycelis muralis, Molinia caerulea, close to stumps. A total of ten traps were placed Oxalis acetosella and Vaccinium myrtillus. at each sampling site. Mosses were abundant; in total 10 moss species were registered. Most of stumps were low and As pitfall traps we used transparent plastic glasses shaded. Soil lichens were not found. Some lichens filled with ethylene glycol diluted with water. were found only on stumps with bark - mostly Trap was dug into the ground so that the rim Cladonia spp. and Lepraria incana. was in one level with the ground surface. These traps were used to catch mobile ground-dwelling O2 – control plot with retained stumps (Fig. insects. Sixteen traps were placed in each 2). The clear-cut area was also covered by sampling site. Pitfall traps were slightly covered naturally regenerated young Betula pendula, with pieces of bark from