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ŠUMARSKI LIST 3-4/2018 str. 48     <-- 48 -->        PDF

how forestry practices such as clear-cutting or selective cutting correspond to natural disturbances and natural forest dynamics. Despite the main type of forest use has remained to be clear-cutting of areas in many places (Carey & Harrington, 2001). Throughout the world, small mammals are important model organisms to investigate the impact of forestry interventions as well as habitat fragmentation and degradation in different forest ecosystems (e.g. Bayne & Hobson, 1998; Fuller et al., 2004; Pardini, 2004; Pardini et al., 2005; Lindenmayer et al., 2010). Small mammals increase species richness and functional diversity in forest ecosystems (Carey & Johnson, 1995). As secondary consumers, small mammals are high density elements of food webs, they have important role in dispersal of fungal spores, ectomycorrhizes, seeds and acorns (Birkedal et al., 2010) and are diverse food resource for terrestrial predators and birds of prey (Carey et al., 1992; Bontzorlos et al., 2005). Due to demographical plasticity, rapid turnover and adaptability (Promislow & Harvey, 1990) both theory and empirical approach consider small mammals as appropriate subjects in the research of demographical patterns and population as well as community level response (Mortelliti et al., 2010). Based on these elements the population and community parameters for forest-floor small mammals can be used as bio-indicators of sustainable forest management (Pearce & Venier, 2005; Sullivan et al., 2013). Trend in indicator species’ distribution and abundance as well as understanding their habitat use and preferences is fundamental for effective conservation and management strategies (Macdonald et al., 1998; Hopkins & Kennedy, 2004; Flowerdew et al., 2004).
The estimation of demographic parameters in natural populations has been recast in the comprehensive framework of capture-mark-recapture (CMR) methodology (Williams et al., 2002; Lebreton, 2006) and has shifted towards the testing of hypotheses of biological interest rather than estimating numerical quantities such as population size, growth and survival rate or direct estimations of recruitment (Lebreton et al., 1992; Pradel, 1996; Nichols et al., 2000).
The bank vole Myodes glareolus (Schreber 1780) is widely distributed species of Myodes genus in the Palaearctic, ranging from the Mediterranean to Scandinavia and from Great Britain to the Black Sea, although it is absent from southern Iberia and the Mediterranean islands (Sptizenberger, 1999). From some population biological aspect the bank vole has proved to be an especially appropriate model object throughout its geographical range (Bujalska & Hansson, 2000) in studies of multiannual vole cycles and population regulation (e.g. Henttonen et al., 1985; Amori, 2000) and social behavior and reproductive success (Koskela et al., 1997; Lemaître et al., 2012) or habitat use in fragmented environment, movement and dispersal strategies (Gliwicz, 1993; van Apeldoorn et al., 1992; Kozakiewicz et al., 2007; Gerlach & Musolf, 2000). Many studies demonstrated that the bank vole is found in all forest habitats throughout its geographical range, preferring dense understorey cover (Mazurkiewicz & Rajska-Jurgiel, 1989; Pucek et al., 1993; Ecke et al., 2002; Suchomel, 2007). According to these studies the bank vole is considered as a habitat generalist species. In contrast, because of its avoidance of open habitats throughout its range, the bank vole was determined by other authors as a habitat specialist (Tattersall et al., 2002; Torre & Arrizabalaga, 2008). The study of the effects of habitat structure on bank vole populations shows that habitat suitability is determined by abundance and spatial distribution (Hansson, 1978; Mazurkiewicz, 1994). Based on numerous studies, the bank vole is a typical forest-dwelling and suitable model species, because it plays an important indicator role in the dynamics of woodland habitats and ecosystem health (Ecke et al., 2002; Flowerdew et al., 2004; Suchomel, 2007) as well as in the evaluation of the impact of forest disturbance and management (Gliwicz & Glowacka, 2000; Gorini et al., 2011; Lešo et al., 2014; 2016). Moreover, bank vole population outbreaks can cause considerable damage in forestry (Imholt et al., 2015) and this rodent species can transmit the Puumala hantavirus to humans (Voutilainen et al., 2012; Bjedov et al., 2016).
As regards protected areas along Drava river small mammals are considered to be an adequate indicator group and suitable monitoring subject for following habitat conditions, different vegetation structure (softwood and hardwood gallery forests) as well as anthropogenic disturbance and forest management activities of remaining forested areas. The biodiversity monitoring of the upper sections of Drava River was started in 2000. Within that high priority programme, small mammal population and community monitoring was run as a sub-programme between 2000-2006 (Horváth et al., 2005; 2012). As part of the Croatian-Hungarian interregional programme (DRAVA-INTERECO), this monitoring could be continued in 2007, this time with an additional forest fragment located in Croatia also being part of the sampling. Thus, now there were three different habitats in which small mammal population monitoring could be pursued, focusing on vegetation structure, forestry management and nature conservation measures. The bank vole was described as dominant species by our survey in the investigated forest habitats of both countries. The response of bank vole to different forest structure, stand composition and traditional and alternative forest management types were often tested by microhabitat association. Numerous studies demonstrated that the high density of bank vole was associated with dense and structurally complex understorey vegetation (Mazurkiewicz & Rajska-Jurgiel, 1989; Chetnicki & Mazurkiewicz, 1994; Miklós & Žiak, 2002; Lešo et al., 2014; Suchomel et al., 2014) where it finds better food availability, shelters and nest sites (Chetnicki & Mazurkiewicz,