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ŠUMARSKI LIST 3-4/2017 str. 40     <-- 40 -->        PDF

deer are forced in extreme winters to consume bark of young spruce, which is often the only available food (Gill 1992, Völk 1999, Ueda et al. 2002). Stands planted on abandoned grassland and pastures, especially those on humid sites where spruce is particularly susceptible to disease, are especially vulnerable. When supplemental feeding sites are located in the vicinity of such stands, the damaging impacts accumulate, which may result in completely destroyed stands (Čampa 1986). Increased culling of red deer is commonly considered the first and only measure to prevent or reduce bark stripping (Putman 1989). Studies however indicate it is often ineffective, as red deer can cause massive bark stripping even at very low densities (Völk 1999, Verheyden et al. 2006). It is more effective to avoid creating such spruce plantations in the first place (Vospernik 2006) or to systematically reduce their favourable cover conditions for red deer by carrying out intensive thinning, which reduces interception of snow and increases its ground thickness. At the same time, more radiation increases bark roughness, which reduces its attraction and accelerates radial growth, and consequently reduces the time such stands are exposed to back stripping (Vospernik 2006, Jerina et al. 2008, Mansson and Jarnemo 2013).
Indirect impacts of wildlife and forest management measures on red deer habitat use within their home range have been confirmed by several studies. Our study is one of the first to demonstrate the impacts of wildlife and forest management measures also at the population level, which suggests that the impacts of the studied factors are much broader and more complex than typically assumed. Neglecting these impacts is therefore particularly damaging, for both red deer and the environment. Wildlife and forest management measures, which impact red deer, also indirectly affect the forest. Measures in both disciplines must therefore be planned in a coordinated manner (Gerhardt et al. 2013). When planning placement of supplemental feeding stations, the distribution of forest stands should be taken into account. The most vulnerable stands – regenerated areas and spruce-dominated pole stands – must be avoided. Feeding can negatively impact red deer fitness and is also a relatively expensive measure (Putman and Staines 2004, Milner et al. 2014). The intensity of feeding should therefore probably be reduced in certain areas. Instead, improvement of more natural resources for wild ungulates can be used as in middle European forestry practise (Weis 1997, Prien 1997). These measures can be implemented through making remises for wild ungulates on deforested land inside, or around forest stands (open strips, brackets, abandoned pastures and meadows etc.). In some parts of Slovenia there is a distinct lack of young growth and regeneration is dispersed, which leads to browsing problems (Jerina 2008); more young growth in large regeneration gaps would mitigate the problem. Pure spruce stands on non-native growing sites are susceptible not only to bark stripping but also to bark beetle outbreaks, fungi and windbreak (Diaci 2006). In Slovenia, intensive planting of spruce is a thing of the past, but in some other European countries the practice remains widespread and should be revised due to the negative impacts associated with red deer.
The results of studies such as ours can be useful directly in wildlife management planning, for example in habitat ranking of hunting grounds. Some European countries, including Croatia, use habitat ranking of hunting grounds for planning of hunting quotas, although the practice is in other countries generally being replaced by more modern methods of adaptive management. Habitat ranking (determining the expected habitat suitability for each species in the hunting grounds) is based on expert knowledge of the species and its habitat preferences (Apollonio et al. 2010, Morellet et al. 2011). Our study, on the other hand, quantitatively evaluated the impact of individual environmental factors on red deer habitat suitability, which could be used for the habitat ranking of given hunting ground. Since the environmental factors were studied at country level, their local effects can deviate from our estimates, which can therefore only be considered as average approximations to reality. In this sense the results of our study underline a shortcoming of habitat ranking: the method assumes that expert knowledge can always and everywhere be applied to reliably evaluate habitat suitability and target densities of red deer or other wild animals. However, this is difficult even with modern analysis of large sets of empirical data.
We thank to Miha Krofel for improving the English, to Sebastijan R. Maček for translation into English and to Vedran Sljepčević for translation into Croatian.
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