Dead Trees Left in Clear-Cuts Benefit Saproxylic Coleoptera Adapted To

Biodiversity and Conservation 6, 1±18 (1997)

Dead trees left in clear-cuts bene®t saproxylic Coleoptera adapted to natural disturbances in boreal forest

LAURI KAILAÃ Finnish Museum of Natural History, Zoological Museum, PO Box 17, FIN-00014 University of Helsinki, Finland

PETRI MARTIKAINEN and PEKKA PUNTTILA Department of Ecology and Systematics, Division of Population Biology, PO Box 17, FIN-00014 University of Helsinki, Finland

Received 27 April 1995; revised and accepted 25 October 1995

Forest management alters the pattern of forest dynamics from that in natural conditions in the boreal region. In order to examine how certain forestry measures matching natural dynamics aect forest insects, we compared assemblages of saproxylic Coleoptera on dead, standing birch trunks left behind in eight clear-cut areas with corresponding assemblages in seven mature forests in southern and eastern Finland. We used trunk-window traps for sampling. Distinct beetle assemblages were associated with the dierent habitats. Median numbers of species or specimens caught did not dier between closed forests and clear-cuts, but individual beetle species occurred unevenly among the habitats. Several beetle species associated with open forest habitat, e.g. burned forests or storm- damage areas, including species regarded as threatened in Finland, were found almost exclusively, in clear-cuts. Correspondingly, a number of beetle species occurring frequently in closed forests were not found in clear-cuts. We conclude that dead trunks left in the clear-cut areas may host not only generalist saproxylic species but also many beetle species specialized to warm, sun-exposed en- vironments, and such species may not be able to survive in closed forests. Management measures matching suppressed natural disturbances are found useful in preserving diversity in managed forests. Keywords: saproxylic Coleoptera; clear-cut; diversity; conservation; management; decaying birch.

Introduction Invertebrate animals associated with the wood-decomposition system form one of the largest groups contributing to the species richness in boreal forests. Such organisms are here called saproxylic, following the de®nition by Speight (1989): `Species of invertebrates that are dependent, during some part of their life cycle, upon the dead or dying wood of moribund or dead trees (standing or fallen), or upon wood-inhabiting fungi, or upon the presence of other saproxylics'. Among the saproxylic organisms, beetles (Coleoptera) form a particularly speciose group: e.g. in Fennoscandia there are about 1300 saproxylic beetle species (unpublished database compiled by J. Stokland). Intensive forest management has reduced the amount of decaying wood in the boreal forests and, as a consequence, large numbers of saproxylic species have declined (e.g. HelioÈvaara and VaÈisaÈnen, 1984; EhnstroÈm and WaldeÂn, 1986; Rassi et al., 1992, VaÈisaÈnen

ÃTo whom correspondence should be addressed. 0960-3115 Ó 1997 Chapman & Hall 2 Kaila et al. et al., 1993). In Finland, for instance, 196 saproxylic invertebrates are regarded as threatened (Rassi et al., 1992), and they have become an important target in the conservation of forest ecosystems. Forest management has not aected all species equally, and certain saproxylic species have even bene®tted from forest management, e.g. several bark beetles breeding in freshly dead trees (Nuorteva, 1968). Most of the declined saproxylic species are associated with the later stages of wood decomposition (EhnstroÈm and Wal- deÂn, 1986). Although the biology of most saproxylic beetles is qualitatively well-known (e.g. Saalas, 1917, 1923; Palm, 1951, 1959), quantitative information on the microhabitat and macrohabitat requirements of individual species is still scarce. Our previous work has focused on microhabitat level: eects of tree species, polypore species and environmental variables on beetle assemblages in decaying trunks (Kaila et al., 1994, and unpublished data). It is obvious that more quantitative information is needed about the fauna in dierent kinds of forest habitat to supplement our knowledge on the macrohabitat requirement of dierent species and ecological groups (but see e.g. BistroÈm and VaÈisaÈnen, 1988, VaÈisaÈnen et al., 1993; Kaila et al., 1994; Siitonen, 1994; Thunes, 1994). So far, attention has been focused mainly on old-growth forests. However, natural disturbances, such as forest ®res, storm damages, and ¯oods caused by beaver, create open, sun-exposed areas with a considerable amount of dying and dead wood. In primeval taiga such patches emerge locally quite frequently (SireÂn, 1955; Zackrisson, 1977, Kuu- luvainen, 1994; SyrjaÈnen et al., 1994), and regionally they may always have been present with moderately small interpatch distances, easily covered by the dispersal capacity of saproxylic beetles. These areas house a number of specialized saproxylic species (e.g. Ahnlund and Linde,1992; Esseen et al., 1992; Berg et al., 1994). Such natural disturbances are nowadays eliminated by eective ®re control and by removing dead trees from windfall gaps and ¯ooding sites. Dead trees left in clear-cut areas are at ®rst glance, essentially similar to naturally disturbed areas as microhabitats for saproxylic insects. To assess the signi®cance of such trees for saproxylic beetles we have studied the dierence between beetle-species assemblages on dead birch trunks located inside mature forest versus trunks left to clear-cut areas after logging. We also discuss the relevance of our results for forestry practice.

Material and methods Sampling method and design The sampling was conducted in two parts. First, we compared saproxylic beetle assemblages on dead birch trunks within closed, mature forests and on open, recently clear-cut areas with some decaying birch trunks left behind, called `comparison sampling' below. Second, we sampled according to a BACI design (before-after-with-control-impact), called `BACI experiment' below (see e.g.Green, 1979). The comparison sampling was performed in two distant localities, in Heinola (61° 10¢ N 26° 08±16¢ E), situated in southern Finland, and in Juva in eastern Finland, (61° 42±45¢ N 28° 000 E). The sampling localities are situated in south-boreal vegetation zone (Ahti et al., 1968). At the time of the sampling, the habit of leaving dead standing trunks in clear-cuts was unfortunately rare, and thus, the number of clear-cut sampling sites is limited in our study. The sampling eort, and the logging years of the clear-cut patches are summarized in Table 1. Saproxylic Coleoptera in clear-cuts 3

Table 1. The number of traps in the sampling sites with logging years of the clear-cut patches. The sampling was performed during the summer of 1993 in all the sites

Location Type of site Number of traps Cutting winter

Heinola Forest 10 ± Heinola Forest 4 ± Heinola Open 7 1990±91 Heinola Open 2 1991±92 Heinola Open 5 1991±92 Juva Forest 3 ± Juva Forest 3 ± Juva Forest 2 ± Juva Forest 1 ± Juva Forest 2 ± Juva Open 3 1992±93 Juva Open 3 1992±93 Juva Open 1 1989±90 Juva Open 1 1991±92 Juva Open 3 1988±89

In Heinola the sampling sites were mixed forests that originated after the end of slash- and-burn cultivation in the late 19th century. Later, the forests were probably used as forest pastures, and they have been slightly managed. In spite of such management, the amount of decaying wood, especially birch, has been relatively high in the area, and we assume that the availability of this microhabitat has been continuous on a regional scale. This assumption is also supported by the occurrence of the white-backed woodpecker (Dendrocopos lecuotos) in the area. This species is dependent on dead deciduous trees, and it is now near extinction in Finland as a consequence of loss of breeding habitats (Virkkala et al., 1993). The sampling was performed from 6 May to 4 October 1993 in three clear-cut areas in Heinola, 200 m±1 km from each other. In these clear-cuts some dead and dying trees had not been removed from the managed areas. We took control samples from two plots in adjacent forest from a distance of, at most, 300 m from the corresponding managed patch. The age of the forests was 70±80 years, and the tree-species composition was birch 40 %, Scots pine 60 %. We estimated the tree-canopy coverage as ca 85 %. The tree-canopy coverage estimations were made from a sample of sighting straight upwards in 20 spots southward from each trap with 1m intervals. The estimations were always made by the same person. In Juva the sampling was performed from 22 May to 2 October 1993 in ®ve clear-cut patches, in distances of 0.5±8 km from each other, and in ®ve control forests in the vicinity of each clear-cut patch. The age of the forests was 70±80 years, and the tree-species composition varied as follows: birch 7±28 %, Scots pine 0±79 %, Norway spruce 5±93 %. In general, the forests were more conifer-dominated than in Heinola. The tree-canopy coverage of the Juva forests was, on average, 70 %. The BACI-experiment sampling included one of the above-mentioned Heinola clear- cuts which was sampled before clear-cutting in 1990 (sampling period from 22 May to 28 September) and again in 1993 (for sampling period, see above). To control variation between dierent years we sampled in a non-managed forest patch in 1990 and in 1993 4 Kaila et al. with the same sampling periods as in the treatment. This sampling plot was situated in Pertunmaa community ca 10 km distant form the Heinola sites. The tree-species composition was birch 67 %, aspen 26 %, alder and Scots pine together 7 %. The tree-canopy coverage was ca 80 %. The polypore species aects the beetle assemblage caught from the trunk, and the perennial polypore Fomes fomentarius hosts a large variety of beetles (Kaila et al., 1994). In order to minimize variation caused by dierent species of fungi, we limited the study to white rotted birch trunks, predominantly decayed by this very common polypore species. No sporocarps of other polypore species were visible on the trunks during the sampling. We collected the samples using trunk-window traps. The trap consists of a 20 CË30cm transparent pane, a plastic funnel below it, and a container (Fig. 1). In the container we used an aqueous solution of sodium chloride as preservative, and a small amount of detergent. A detailed description of the trap and trapping method used is given in Kaila (1993). The traps were attached to standing trunks. The deposition height varied between 0.5 and 2.5 m, measured from the lower margin of the window. The deposition height of the traps did not dier systematically (Kruskal-Wallis non-parametric one-way ANOVA p = 0.88) among the treatments. The traps were placed close to living sporocarps of F. fomentarius. If the sporocarp was broader than 8 cm, we wedged the window into the sporocarp. This apparently did not aect the sporocarps, as they rapidly grew tightly against the window, and we could not observe any desiccation of sporocarps due to

Figure 1. The trunk-window trap used in the sampling (after Kaila, 1993). Saproxylic Coleoptera in clear-cuts 5 wedging. The thickness and height of the trunks were comparable in experiments; only trunks at the Pertunmaa site were signi®cantly thicker compared to those in pooled forest- control trunks in Heinola, and Juva (Kruskal-Wallis non-parametric one-way ANOVA with Tukey-type a-posteriori comparisons, p < 0.05). In the clear-cut patches the minimum distance for the trunks used for sampling was 15 m from the forest margin.

Beetle species included in the analyses The species included in the study are saproxylic in their living habits and are known to be associated with deciduous trees, according to the available literature. As the main references for the living habits we used Saalas (1917, 1923, 1949), Hansen (1950, 1951), Palm (1951, 1959) and Benick (1952). The nomenclature follows Silfverberg (1992). The families Latridiidae and Cryptophagidae, as well as the genus Epuraea (Nitidulidae) were excluded from the analyses because of identi®cation problems. For the same reason, only genera Lordithon and Carphacis from the family Staphylinidae were included. Scolytids were excluded form the analyses, since they are associated with recently dead trees. These excluded groups made up roughly 20 % of the individuals of the whole material of saproxylic species. The families included in the analyses are presented in Table 2.

Statistical treatments We used detrended correspondence analysis (DCA, Ter Braak, 1987) to reveal major ecological gradients in the two data sets. The data were not transformed, all the species were given equal weight, and the detrending was done by 10 segments. The analyses were performed using CANOCO software (Ter Braak, 1987).

Table 2. The beetle families included in the analyses, with the total number of saproxylic species associated with deciduous trees in the present data

Family Species Family Species

Aderidae 1 Lycidae 2 Anobiidae 9 Lymexylidae 1 Anthribidae 1 Melandryidae 6 Carabidae 1 Mordellidae 3 Cerambycidae 7 Mycetophagidae 5 Cerylonidae 3 Nitidulidaea 7 Cisidae 13 Pyrochroidae 1 Colydiidae 2 Rhizophagidae 7 Cucujidae 2 Salpingidae 3 Dermestidae 3 Sphindidae 2 Elateridae 10 Staphylinidaeb 6 Endomychidae 1 Stenotrachelidae 1 Erotylidae 6 Tenebrionidae 5 Eucnemidae 2 Tetratomidae 1 Histeridae 1 Trogossitidae 1 Hydrophilidae 1 Leiodidae 14 Total 129 Lucanidae 1

aExcluding Epuraeini. bOnly genera Lordithon and Carphacis included. 6 Kaila et al. The numbers of individuals and species in forests versus clear-cut areas were compared by Kruskal-Wallis non-parametric one-way ANOVA with Tukey-type a posteriori comparisons (Zar, 1984). It is questionable whether samples from individual trunks within patches are independent from each other. Variation among samples from dierent trunks within patches, however, appeared similar to variation among samples from dierent patches. Therefore we regarded it as justi®ed to use trap samples as independent units in all comparisons regardless of the numbers of traps per patch (see also Discussion). We compared the expected numbers of species in standardized samples among the treatments with rarefaction (Simberlo, 1978).

Results The two data sets comprised 10 248 individuals belonging to 129 species (Appendix 1). The most abundant species were Triplax russica, Dorcatoma robusta, Lordithon lunulatus, An- isotoma glabra and A. humeralis. These ®ve species comprised ca 57 % of the total sample. The most frequently caught species were D. robusta (caught in 69 of the 74 traps), A. glabra (68), A. humeralis (68), Bolitophagus reticulatus (67), T. russica (66) and L. lunulatus (63). In DCA ordinations the clearest variation in the beetle assemblage was between closed versus open forest (Figs 2 and 3). As in ordinations, there was only little overlap in sampling sites of open versus closed forests; these sites thus harboured dierent beetle fauna. As there was no evident biogeographic gradient in the comparison of the sites within Juva and Heinola, respectively, we found it justi®ed to pool the data sets in these two locations for the analyses below. In the comparison sampling, there were no great dierences in the expected numbers of species in samples standardized to equal sample size among the open and closed forests in

Figure 2. DCA ordination of the samples of Figure 3. DCA ordination of the samples in the clear-cut and mature forests according to their BACI experiment according to their beetle beetle samples (comparison sampling). Solid samples. Solid symbols = before treatment (year symbols = closed forest; open symbols = clear- 1990); open symbols = after treatment (1993); cut forest; square = Heinola; triangle = Juva. square = control forest; triangle = experiment The eigenvalues of the DCA-axes are given in forest (clear-cut in winter 1990±91). The eigen- parentheses. values of the DCA-axes are given in parentheses. Saproxylic Coleoptera in clear-cuts 7

Figure 4. The expected number of species E(S), Figure 5. The median sample sizes (quartiles, with 2 SD in the samples from closed and clear- minimum and maximum) of the total numbers cut forests in Heinola (H) and Juva (J) calcu- of beetles and species in the trap samples from lated for 100 (open symbols) and 500 (solid mature forests and clear-cuts in Heinola (H) and symbols) individuals (comparison sampling). Juva (J). The letter code indicates signi®cant dierences among the samples (only sites not sharing a letter diered from each other). Dierences larger than 2 SD are regarded as signi®cant.

Heinola and Juva (Fig. 4). The only signi®cant dierence was between Juva forest and Heinola clear-cut. The median sample sizes and the median number of species were similar among the treatments (Fig. 5). In the BACI experiment, the expected number of species in samples standardized to equal sample sizes was signi®cantly higher in the treatment forest after the clear-cutting (Fig. 6). The clear-cutting resulted in reduced median sample sizes, whereas the median number of species remained at the same level as it was in the control and in the same area before the clear-cutting (Fig. 7). This pattern presumably followed on from the smaller catch of mature-forest species after the management on one hand, and slow colonization of the open-country species on the other hand. Occurrences of individual species among the treatments The abundant species that occurred proportionally more numerously in either clear-cuts or closed forests in our samples are summarized in Table 3. The species Litargus connexus, Mycetophagus piceus, Lygistopterus sanguineus, Anisotoma axillaris, Sphindus dubius, as well as click-beetles (Elateridae) in general, occurred almost exclusively in the samples from clear-cuts. Anisotoma humeralis, Lordithon speciosus, Triplax russica, Dorcatoma 8 Kaila et al.

Figure 6. The expected numbers of species E(S), Figure 7. Median sample sizes (quartiles, mini- with 2 SD in the samples from the BACI ex- mum and maximum) of the total numbers of periment before and after the treatment calcu- beetles and species in the traps in the forest- lated for 100 (open symbols) and 500 (solid cutting experiment (BACI) in the treatment symbols) individuals. The letter code indicates forest and in the control before and after the signi®cant dierences among the samples (only cutting. sites not sharing a letter diered from each other). Dierences larger than 2 SD are regarded as signi®cant. dresdensis and Arpidiphorus orbiculatus tended to occur more frequently in samples from forest. Occurrences of rare beetles (at most, 50 localities of occurrence known in Finland during 1960±1989, according to Rassi (1993) among the pooled Heinola and Juva clear-cut samples, and corresponding control samples are presented in Table 4. In the clear-cut and closed-forest samples the pooled numbers of such species and their total number of individuals were of equal size. Individual species, however, tended to show a dierent occurrence pattern among the treatments. All the 13 individuals of Denticollis borealis, for instance, were caught in the clear-cuts. Twelve of the total ®fteen individuals of Myce- tophagus quadripustulatus were captured in the forest. Three species considered as threatened (placed in the category of `in need of monitoring') in Finland were found in the clear-cuts: Peltis grossa, M. quadripustulatus and Tomoxia bucephala. The following ®ve threatened species were found in forest: M. quadripustulatus, P. grossa, Scotodes annulatus, Triplax ru®pes and T. bucephala. In addition, Carphacis striatus was found in the forest samples of the BACI experiment. In our material, two beetle species, Denticollis borealis and Laemophloeus muticus, that, according to Wikars (1992), are pyrophilous (de®ned as `species that are strongly attracted Saproxylic Coleoptera in clear-cuts 9

Table 3. The species most distinctly present in either clear-cuts or forest, with percentages of the individuals in samples from clear-cuts of the total sample for each locality. In Heinola only species occurring in at least ®ve trap samples are included. In Juva the corresponding number is four. N=number of individuals. The full species names are given in Appendix 1

Heinola Juva

Clear-cut % (N) % (N)

Lyg. sanguineus 100.0 (51) Sph. dubius 100.0 (19) Den. borealis 100.0 (13) Lyg. sanguineus 100.0 (13) Bit. crenata 100.0 (10) Ani. axillaris 95.5 (269) Lit connexus 96.3 (82) Myc. piceus 90.0 (61) Myc. piceus 94.7 (95) Gli. quadripustul. 88.9 (27) Ani. axillaris 94.6 (56) Lit. connexus 88.9 (9) Amp. pomorum 94.4 (18) Amp. balteatus 88.2 (16) Amp. balteatus 94.1 (17) Amp. nigrinus 87.5 (8) Pla. albinus 93.3 (15) Rhi. bipustulatus 87.0 (24) Sph. dubius 93.1 (29) Amp. pomorum 83.3 (7)

Forest % (N) % (N)

Lor. speciosus 0.0 (13) Orc. micans 8.1 (37) Arp. orbiculatus 7.5 (40) Hyl. dermestoides 11.1 (9) Tri. aeneus 11.1 (9) Tri. russica 11.5 (131) Aga. confusum 11.8 (17) Gli. hortensis 13.6 (22) Ani. humeralis 13.6 (285) Dor. dresdensis 14.3 (35) Rhi. dispar 17.5 (57) Cis. jacquemartii 17.0 (47) Rhi. cribratus 19.0 (63) Sal. ru®collis 18.2 (11) Myc. quadripustul. 21.4 (14) Dor. robusta 20.8 (236) Dor. dresdensis 25.0 (24) Lor. speciosus 22.2 (15) Tri. russica 23.7 (473) Ani. humeralis 26.2 (118) to burning or newly burnt areas, and species that have their main occurrence in burned forest 0±5 years after the ®re' (Wikars, 1992)) occurred in samples from the clear-cuts. The survival ability of such species in warm conditions, even without ®res, indicates that some of these species may be preserved, although probably in lowered densities in managed forests, if there is available suitable microhabitat for breeding.

Discussion For successful conservation it is necessary to know where dierent species exist and where they do not exist on both a regional and habitat scale, and also to know the speci®c requirements of individual species. For this purpose, survey-like studies are irreplaceable (e.g. Margules and Austin, 1991; Haila and Levins, 1992; Haila, 1992, 1994). Preliminary conclusions on the eect of forest-management practice on the beetles can be drawn on the basis of descriptive, assemblage-level data, and patterns observed give guidelines for later studies on the requirements of individual species. Suitable methods of systematic surveys may be e.g. sampling along gradients of environmental types or pairwise comparisons of distinctly dierent habitat types. Such studies enable estimation of how the variation of habitats is re¯ected in species assemblages (e.g. Austin, 1986, 1991; Haila, 1994; Kaila et al., 1994). 10 Kaila et al.

Table 4. Rare species (at most, 50 known localities of occurrence in Finland during 1960±1989) in comparison sampling, with samples from Heinola and Juva pooled. The species regarded as threatened in Finland are marked with an asterisk ( ) Ã Species Number of individuals

Clear-cut Forest

Amphicyllis globiformis ±1 Denticollis borealis 13 ± Dorcatoma punctulata 13 Globicornis emarginata 6± Hadraule elongatula 1± Hylis procerulus 1± Ipidia binotata ±4 Laemophloeus muticus 3± Lordithon pulchellus ±1 Lordithon trimaculatus ±1 Mycetophagus quadripustulatus 312 Ã M. decempunctatus 26 M. populi 2± Peltis grossa 41 Ã Priobium carpini 1± Rhizophagus parallelocollis 1± R. nitidulus 46 Scotodes annulatus ±1 Ã Tomoxia bucephala 31 Ã Triplax ru®pes ±2 Ã Tritoma bipustulata 21 Total 15 spp. / 47 ind. 13 spp. / 40 ind.

In the present study a pairwise comparison of open habitats and closed forests shows that both types of habitat harbour large numbers of saproxylic beetle species, including a fraction of threatened and rare species. The species composition, as well as the relative abundances of the species, showed dierences between the habitats. We observed rather strict habitat specialists among both the common and rare, even threatened species. Thus, besides the quality of the decaying trunks (Kaila et al., 1994), various environmental factors appear to aect the occurrence of both common and rare saproxylic insect species. The saproxylic organisms may form several types of `microecosystems' depending on the environmental conditions (Haila, 1994; Kaila et al., 1994). This result emphasizes the need for availability of widely dierent habitats: only a part of the saproxylic fauna is able to inhabit old forests. In contrast to the dierence between the habitats, the samples from trunks within the closed forests and clear-cuts, respectively, were rather homogenous. A high level of mobility of the beetles within a habitat could explain the pattern observed (see also Siitonen, 1994). However, the mobility of the species is, in general, poorly known, and most probably it varies remarkably between species. Most individuals of Bolitophagus reticulatus, for instance, stay for a long time, and perhaps spend their whole life-time on the same trunk (T. Nilsson, pers. comm.). In contrast, certain spore-feeders, such as Triplax russica, have appeared to be very mobile (personal observation). One evident explanation Saproxylic Coleoptera in clear-cuts 11 for the pattern observed is that similar microhabitat patches, in this case dead birch trunks, tend to be occupied by similar species assemblages on the local scale. The numbers of species and individuals were of similar size both in our samples from trunks in the clear-cuts and in those within closed mature forest. A potential source of bias in this overall picture in our results comes from the evident dierence of the mobility of the beetles in dierent temperature conditions (Greenslade, 1964; Assing, 1993). Numbers of individuals caught from the sun-exposed clear-cuts can be assumed to be exaggerated compared to samples from closed forests because of higher mobility in warm conditions. Our main result was, however, a qualitative dierence in the beetle assemblages between open and shady conditions. A general trend of rising mobility in warmer conditions aecting all species in a similar way would not lead to such a pattern. Protected forest areas are, especially in southern Finland, small, and they are often a great distance from each other. These areas have been established to preserve old forests, and they are, in general, too small to maintain natural disturbance dynamics. As important as the protected forest areas are for the conservation of an immense number of saproxylic organisms, the conservation of forest-species diversity cannot be based solely on them. Forestry practice in managed forests, designed to take the diversity into account, is crucial for maintaining the species richness. In forestry, the natural processes should be matched as closely as possible (Haila et al., 1994 and references therein; McNeely, 1994). To ensure the survival of species associated with natural disturbances, the availability of decaying wood in sun-exposed conditions appears crucial (see also Ahnlund and Linde, 1992; Siitonen and Martikainen, 1994). A number of such saproxylic species that are adapted to disturbed conditions are favoured by simple and cheap practices such as leaving all the wood that is of little or no commercial use, e.g. dead wood and old or damaged trees, to logging ares. Such measures may, according to the present ®ndings, provide breeding habitats for a number of such saproxylic species that have been de- clining, and even for certain threatened species. However, this general result will need further experimental studies for assessing well supported recommendations in respect of e.g. quantities of wood that should be left behind in managed areas. Evaluation of the possible practical problems for logging, as well as costs of such practices, should also be considered in order to ®nd generally ac- ceptable ways of incorporating the diversity aspects of forestry.

Acknowledgements Y. Haila, J. Siitonen and two anonymous referees made valuable comments on the manuscript. L. Kauppi made our study possible by his logging design suitable for our purpose. M. Aitolehti and S. BjoÈrkholm helped in sorting the material. T. Vuorinen made the illustration of the trap. This paper forms a part of a larger research project on the eects of forestry on animal populations ®nanced by the Academy of Finland, and Maj and Tor Nessling foundation. We should like to thank all these persons and institutions.

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(1955) The development of spruce forest on raw humus site in northern Finland and its ecology. Acta Forest. Fennica 62, 1±362. Speight, M.C.D. (1989) Saproxylic Invertebrates and their Conservation. Strasbourg: Council of Europe. SyrjaÈnen, K., Kalliola, R., Puolasmaa, A. and Mattson, J. (1994) Landscape structure and forest dynamics in subcontinental Russian European taiga. Ann. Zool. Fennici 31, 19±34. Ter Braak, C.J.F. (1987) CANOCO±A FORTRAN program for canonical community ordination by partial detrended canonical correspondence analysis, principal component analysis and redundancy analysis. Wageningen, The Netherlands: TNO Institute of Applied Computer Science. Thunes, K.H. (1994) The coleopteran fauna of Piptoporus betulinus and Fomes fomentarius (Aphyllophorales: Polyporaceae) in western Norway. Entomol. Fennica 5, 157±68. Virkkala, R., Heinonen, M. and Routasuo, P. (1993) Population contraction of the white-backed woodpecker Dendrocopos leucotos in Finland as a consequence of habitat alteration. Biol. Conserv. 66, 47±53. VaÈisaÈnen, R., BistroÈm, O. and HelioÈvaara, K. (1993) Subcortical Coleoptera in dead pines and spruces: is primeval species composition maintained in managed forests? Biodiv. Conserv. 2, 95± 113. Wikars, L.-O. (1992) Forest ®re and insects. Entomologisk Tidskrift 113, 1±11. Zackrisson, O. (1977) In¯uence of forest ®res on the North Swedish boreal forest. Oikos 29, 22±32. Zar, J.H. (1984) Biostatistical Analysis, 2nd edn. Englewood Clis, N J: Prentice-Hall. 14 Appendix 1. Total catches of beetles in the trapsets in the closed forest Ð clear-cut comparison and the BACI-experiment sorted by the abundance in closed-forest sets in Heinola and Juva. Also the totals (abundance and frequency) in the 74 traps are given. Note that Heinola-Clear-cut includes the Treatment-After traps (7 traps). H = Heinola, J = Juva, B = Before, A = After, Ab. = abundance, Fr. = frequency.

Species Closed vs Clear-cut BACI

Closed Clear-cut Control Treatment Total

H J H J B A B A Ab. Fr.

Triplax russica 361 116 112 15 244 760 474 37 2082 66 Dorcatoma robusta 166 187 230 49 155 239 307 101 1333 69 Anisotoma humeralis 246 87 39 31 119 126 93 12 741 68 Lordithon lunulatus 141 129 101 130 214 132 72 47 919 63 Anisotoma glabra 93 143 157 309 17 57 27 77 803 68 Bolitophagus reticulatus 117 72 129 47 44 92 74 48 575 67 Glischrochilus hortensis 154 19 69 3 62 135 16 11 458 42 Rhizophagus cribratus 51 73 12 32 44 92 26 8 330 52 Cis jacquemartii 46 39 31 8 8 45 32 20 209 48 Orchesia micans 20 34 8 3 44 34 41 8 184 43 Dorcatoma dresdensis 18 30 6 5 28 17 18 5 122 42 Aripidiphorus orbiculatus 37103537116621 Rhizophagus dispar 47±1036±±56620 Agathidium seminulum 16 13 5 8 5 10 ± 1 57 31 Ropalodontus strandi 14 12 25 27 17 24 21 15 140 48 Lordithon speciosus 13 11 ± 4 41 19 27 ± 115 34 Agathidium confusum 15824331±3621 Melanotus castanipes 913152227867636 Rhizophagus depressus ± 22 ± 8 ± 24 ± ± 54 18 Pocadius ferrugineus 21±9411±±3610 Cerylon ferrugineum 10983120235323 Mycetochara ¯avipes 3 16 9 6 2 10 9 7 55 28 Rhagium mordax 10 8 27 5 6 10 8 17 74 29 Hylecoetus dermestoides 88101±6123422

Anisotoma axillaris 3 12 53 257 6 ± 1 23 332 31 Kaila Rhizophagus bipustulatus 11 4 14 20 16 28 9 6 102 36 Salpingus ru®collis 594211±±2216

Mycetophagus quadripustulatus 1113±1±111713 al. et Xylita laevigata 10261±±±1198 arxlcClotr nclear-cuts in Coleoptera Saproxylic Appendix 1. (continued)

Species Closed vs Clear-cut BACI

Closed Clear-cut Control Treatment Total

H J H J B A B A Ab. Fr.

Mycetophagus piceus 5 6 90 54 6 9 6 66 176 42 Cis hispidus 821±261±2015 Triplax aeneus 82112±111511 Cis boleti 544846±33121 Orthocis alni 172321211815 Rhizophagus parvulus 625143±±2116 Ampedus nigrinus 61207±1133623 Dacne bipustulata 6 1 49 4 3 13 21 36 97 36 Ennearthron cornutum 3311±±11 98 Mycetophagus decempunctatus 42±246±±1812 Rhizophagus nitidulus 3322561±2216 Anisotoma castaneus 4145116143212 Cerylon histeroides 414138112218 Glischrochilus quadripunctatus 23424±2123616 Agathidium nigripenne 31±±24±±108 Ipidia binotata 4±±±±±1± 53 Litargus connexus 3 1 79 8 2 9 7 40 109 34 Anisotoma orbiculatus 3±1143±±127 Cis comptus 125±±143139 Cychramus variegatus ±3±1±±±± 43 Dorcatoma punctulata 3±1±111± 77 Ennearthron laricinum 3±±±3±±± 65 Ampedus balteatus 111615±±±83316 Anobium ru®pes 114±±±±2 66 Lordithon thoracicus 11±±±±±± 22 Sphindus dubius 2 ± 27 19 ± ± ± 10 48 20 Triplax ru®pes 11±±±±±± 22 Triplax scutellaris 11±±11±± 44 Agathidium rotundatum 1±1±±±±1 22 Ampedus erythrogonus ±1±±±±±± 11

Amphicyllis globiformis 1±±±±±1± 22 15 16 Appendix 1. (continued)

Species Closed vs Clear-cut BACI

Closed Clear-cut Control Treatment Total

H J H J B A B A Ab. Fr.

Ampedus pomorum 1 ± 17 7 ± ± 1 13 26 15 Cis alter ± 11±±±±122 Cychramus luteus ± 1±±111±44 Dendrophagus crenatus ± 1±±±±±±11 Denticollis linearis 1 ±31111±88 Diaperis boleti 1 ±±15±±±74 Endomychus coccineus 1 ±1±±±2144 Globicornis emarginata ± 16±±±±673 Hallomenus axillaris ± 1±±±±±±11 Hadrobregmus confusus ± 1±±±1±±22 Leptura quadrifasciata 1 ±±1±±±±22 Lordithon pulchellus 1 ±±±±1±±22 Lordithon trimaculatus 1 ±±±±±±±11 Octotemnus glabriculus ± 1±±±±±±11 Peltis grossa 1 ±4±±±±454 Platystomos albinus 1 ± 14 1 ± ± ± 11 16 10 Platycerus caprea ± 111±4±175 Salpingus planirostris 1 ±±±24±±76 Scotodes annulatus 1 ±±±±±±±11 Scaphidema metallicum ± 11±1±±±33 Synchita humeralis ± 1±±±11±33 Tomoxia bucephala ± 13±±±±243 Tritoma bipustulata 1 ±±2±±±±33 Abdera anis ± ±3±±±±233 Acanthoderes clavipes ± ±±±±±1±11 Agathidium badium ± ±±±±1±±11

Agathidium nigrinum ± ±±±±1±±11 Kaila Agathidium pisanum ± ±±±42±±65 Amphicyllis globus ± ±±4±±±±42

Ampedus pomonae ± ±41±±±155 al. et Ampedus tristis ± ±33±±±264 arxlcClotr nclear-cuts in Coleoptera Saproxylic Appendix 1. (continued)

Species Closed vs Clear-cut BACI

Closed Clear-cut Control Treatment Total

H J H J B A B A Ab. Fr.

Anostirus castaneus ± ±2±±±±±21 Attagenus schaeferi ± ±4±±±±243 Bitoma crenata ± ±10±±±±7107 Carphacis striatus ± ±±±±2±±22 Cerylon fagi ± ±11±2±±44 Cis lineatocribratus ± ±±11±±±22 Denticollis borealis ± ±13±±113159 Pyropterus nigroruber ± ±±1±±±±11 Dorcatoma substriata ± ±±±9±±±91 Euglenes pygmeus ± ±23±±±±53 Hallomerus binotatus ± ±±±±1±±11 Hadraule elongatula ± ±1±±±±±11 Hylis procerulus ± ±1±±±±±11 Judolia sexmaculata ± ±±1±±±±11 Laemophloeus muticus ± ±21±±±±33 Anoplodera maculicornis ± ±±1±±±±11 Leptura melanura ± ±1±±±±111 Lygistopterus sanguineus ± ± 51 13 ± ± ± 9 64 13 Megasternum obscurum ± ±±11±±±22 Megatoma undata ± ±1±±±±111 Microrhagus pygmaeus ± ±±±±1±±11 Mordella holomelaena ± ±64±±±2107 Mordellistena humeralis ± ±±±±±1±11 Mycetochara axillaris ± ±±±±2±±21 Mycetophagus populi ± ±2±±2±143 Necydalis major ± ±±±1±1±22 Orchesia fasciata ± ±±±±1±±11 Pityophagus ferrugineus ± ±231±1±76 Platycis minuta ± ±2±±±±122 Priobium carpini ± ±±1±±±±11

Ptilinus fuscus ± ±±1±±±±11 17 18 Appendix 1. (continued)

Species Closed vs Clear-cut BACI

Closed Clear-cut Control Treatment Total

H J H J B A B A Ab. Fr.

Rabocerus foveolatus ±±±±±21± 33 Rhizpohagus parallelocollis ±±1±±±±1 11 Schizotus pectinicornis ±±1±±±±1 11 Soronia punctatissima ±±21±±±1 33 Sulcacis anis ±±21±±±± 33 Tachyta nanus ±±±1±±±± 11 Tetratoma ancora ±±±1±±±± 11 Total number of individuals 1762 1149 1586 1227 1166 2026 1332 718 10248 Total number of species 69 62 81 73 54 62 50 63 129 Total number of traps 14 11 14 11 7 10 7 7 74 Kaila tal. et