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ŠUMARSKI LIST 3-4/2017 str. 39     <-- 39 -->        PDF

of European countries: the imminent extinction of red deer was followed by reintroduction or immigration in the 19th and 20th century, which led to gradual population increases. In the subsequent decades the abandonment of agriculture further contributed to increasing population trend of red deer and other ungulates around Europe (Apollonio et al. 2010, Scandura et al. 2014).
Aside from past human activities, local red deer population densities are significantly influenced by our present-day interventions, in particular wildlife and forest management measures. Unlike past activities which we cannot influence, present-day management measures can be adjusted at will to achieve the desired impacts on red deer and, consequently, on the environment. The biggest limitation thereof is the often poor knowledge of the strength and complexity of the impacts these measures have on red deer, rendering it difficult to properly target them (Putman 1996, Weisberg and Bugmann 2003).
The inherent complexity of direct and indirect effects of supplemental feeding on red deer is a typical example. Hunters across Europe feed red deer with the aim to attract it and increase its fitness and trophy value. Researchers and forest managers, on the other hand, consider the measure highly controversial due to the potentially undesired impacts on forest (Putman and Staines 2004, Milner et al. 2014). Feeding undoubtedly impacts space use of red deer; numerous studies showed that red deer intensely use supplemental feeding stations and their surroundings and that supplementary feeding reduces annual home ranges of red deer (Luccarini et al. 2006, Perez-Gonzalez et al. 2010, Ferretti and Mattioli 2012, Jerina 2012, Reinecke et al. 2014). The results of our study indicate that the impact of feeding stations is even much broader: they increase densities at the meso-population level as well, thereby augmenting the environmental impacts of red deer. Probably the most common negative impact of feeding is over-browsing and bark stripping in the vicinity of feeding stations, which has been shown by several studies (Ueckermann 1983, Schmidt and Gossow 1991, Nahlik 1995). Red deer which visits feeding stations almost never consume exclusively supplementary feed, but also forages natural vegetation in the vicinity (up to several 100 meters) of the feeding stations to balance their dietary needs (Adamič 1990, Schmitz 1990).
Supplemental feeding is often practised to increase animals’ trophy value and fitness, but the results are often the opposite from expectations of hunters and wildlife managers. Whereas few studies have shown positive impacts of feeding on red deer fitness and others have not detected any impacts, numerous studies even demonstrated negative impact on red deer body mass and in some cases even increased mortality as a consequence of supplemental feeding (for review see Milner et al. (2014)). High density of red deer at supplemental feeding stations can strongly increases intraspecific competition for food. Especially females and younger animals visiting feeding stations are often displaced by stags, which undermines the fitness of these social groups (Wiersema 1974, Schmidt 1992, Seivwright 1996, Putman and Staines 2004). Another cause of decreased fitness and higher mortality is facilitated transmission of disease and parasites among individuals due to their high concentrations at supplemental feeding sites (Hines et al. 2007, Cross et al. 2010, Scurlock and Edwards 2010).
Whereas wildlife management measures are targeted at improving red deer habitat, forest management measures are predominantly aimed at wood production; their impacts on red deer, and indirectly on forest, are often completely overlooked. By changing the age-class ratio and tree species composition, forestry impacts key components of red deer habitat suitability: food abundance and presence of security and snow interception cover (Adamič 1990, Reimoser and Gossow 1996, Kramer et al. 2006, Kuijper et al. 2009, Heinze et al. 2011).
Similar as in past studies, bivariate correlation in our study indicates a positive impact of forest regeneration abundance on red deer density. In accordance with the optimal bite selection theory, which states that diet selection is affected by quality as well as abundance of food (Iain and Herbert 2008), red deer often concentrates in forest regeneration gaps (Reimoser and Gossow 1996, Kuijper et al. 2009). However here, unlike in the case of concentrations at feeding stations, the effect on regeneration capacity of forest is in general favourable. In larger regeneration gaps (and in sylvicultural systems with larger proportion of regeneration areas) red deer is practically saturated with food, therefore it cannot compromise successful recruitment of young growth (Storms et al. 2006). At the same time regeneration gaps attract red deer from parts of forest with more dispersed regeneration which is more exposed to browsing (Stergar 2005, Jerina 2008). In general, for successful mitigation of negative impacts of ungulates on forest, wildlife management as well as forest management measures have to be adjusted accordingly: sufficient presence and abundance of forest regeneration and selection of a sylvicultural system that provides herbivores with more food and consequently reduces browsing.
In addition to forest regeneration gaps, red deer also selects spruce-dominated pole stands as shown in our analysis, however the effect on forest in this case is completely opposite. Spruce pole stands are very appealing, but at the same time a poor-quality habitat, i.e. an ecological trap (Adamič 1990, Reimoser and Gossow 1996). Snow interception and favourable thermal cover make spruce-dominated pole stands popular wintering areas for red deer, but since the availability of food in such stands is very low, red