Slovenia Forest Service

Ljubljana, Slovenia

Slovenia Forest Service

Ljubljana, Slovenia
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Sturm T.,Slovenia Forest Service | Podobnikar T.,University of Ljubljana
International Journal of Wildland Fire | Year: 2017

The aim of this study is to develop a long-term forest fire occurrence probability model in the Karst forest management area of Slovenia. The target area has the greatest forest fire occurrence rates and the largest burned areas in the country. To discover how the forest stand characteristics influence forest fire occurrence, we developed a long-term linear regression model. The geographically weighted regression method was applied to build the model, using forest management plans and land-based datasets as explanatory variables and a past forest fire activity dataset as a predicted variable. The land-based dataset was used to represent human activity as a key component in fire occurrence. Variables representing the natural and the anthropogenic environment used in the model explained 39% of past forest fire occurrences and predicted areas with the highest likelihood of forest fire occurrence. The results show that forest fire occurrence probability in a stand increases with lower wood stock, lower species diversity and lower thickness diversity, and in stands dominated by conifer trees under normal canopy closure. These forests stand characteristics are planned to be used in forest management and silviculture planning to reduce fire damage in Slovenian forests. © IAWF 2017.

Stergar M.,Slovenia Forest Service | Jerina K.,University of Ljubljana
Sumarski List | Year: 2017

Red deer (Cervus elaphus L.) is in many parts of the world ecologically important and highly popular game species. Its population densities and environmental impacts largely depend on habitat suitability, which in turn is under strong influence of humans. Wildlife management intentionally improves habitat suitability, while forestry's impacts on red deer are mostly unintentional. In both disciplines the full extent of these impacts is poorly understood. To better understand habitat use and improve management of red deer, we studied the impacts of multiple environmental and historical factors, mostly anthropogenic, on red deer spatial distribution in Slovenia. We found that the probability of red deer presence and population density are higher close to locations of historic (> 100 years ago) red deer reintroduction sites and in large continuous forest complexes. The finding is important for forecasting future red deer distribution and population dynamics. Population density is also positively dependent on proximity to supplemental feeding sites, the proportion of spruce stands in pole-stage and the share of forest young growth, which is important for preventing unwanted impacts of red deer on forest. The approach used by this study and its results are also useful for improving habitat ranking of hunting grounds, which some countries use in wildlife management planning.

Krofel M.,University of Ljubljana | Jonozovic M.,Slovenia Forest Service | Jerina K.,University of Ljubljana
Ursus | Year: 2012

Harvesting wild animals can affect demographic parameters and life history traits of surviving individuals. Most brown bear (Ursus arctos) populations currently experience low levels of hunting. We characterized mortality patterns in a heavily exploited transboundary brown bear population in Slovenia, Central Europe. Overall, 927 brown bears were reported removed from 1998 to 2008. Most (97%) removals were human caused including removals from hunting (59% of removals), management removals of problem individuals (18%), and vehicle collisions (16%). Median age of bears removed in Slovenia was 2.3 years, and 78% of bears removed were <4 years old. Removal was male-biased overall (59%), mainly due to the high percent (49%) of young (<4 years old) males removed during hunting, a possible consequence of sex-related differences in bear behavior and harvest regulations. However, the effect of sexbiased removal was less than expected based on removal data, and it appears a different harvest regimen in neighboring Croatia and sex-biased dispersal of young bears buffered the demographic effects of selective harvest in Slovenia. We also observed that annual proportion of females in harvests increased with harvest intensity. More males were removed among younger classes, whereas females started to dominate above the age of 8 years. About 20% of the brown bear population was removed annually by legal harvest; this is one of the highest harvest rates reported for this species. © International Association for Bear Research and Management.

Jerina K.,University of Ljubljana | Jonozovic M.,Slovenia Forest Service | Krofel M.,University of Ljubljana | Skrbinsek T.,University of Ljubljana
European Journal of Wildlife Research | Year: 2013

Solid understanding of species' range and local population densities is important for successful wildlife management and research. Specific behavioral and ecological characteristics make brown bear Ursus arctos a difficult species to study. We present a map of range and local population densities of brown bears in Slovenia, made with the use of a new approach similar to voting classifications based on a combination of four datasets: Global Positioning System telemetry data, records of bear removals, systematic and opportunistic direct observations and signs of bear presence, and noninvasive genetic samples. Results indicate that the majority of bears in Slovenia live in Dinaric Mountains in the southern part of the country where local bear population densities exceed 40 bears/100 km2. This is one of the highest population densities reported so far for this species worldwide. Population densities decrease towards the north (Alpine region) and are very low along the border with Italy and Austria where almost no females are present. This explains slow past and present expansion of this transboundary bear population into the Alps and should be considered in future bear re-colonization management strategies. Results also showed that data from observations and removals overestimate bear population densities at low values, while mortality and genetic data overestimate population densities in areas with more people. Nevertheless, all data types appeared useful for describing the general bear distribution patterns. Similar approach could be applied to studies of other charismatic or game species, for which several types of data are often available. © 2013 Springer-Verlag Berlin Heidelberg.

Molinari-Jobin A.,KORA | Kery M.,Swiss Ornithological Institute | Marboutin E.,ONCFS | Molinari P.,Italian Lynx Project | And 8 more authors.
Animal Conservation | Year: 2012

Inferring the distribution and abundance of a species from field records must deal with false-negative and false-positive errors. False-negative errors occur if a species present goes undetected, while false-positive errors are typically a consequence of species misidentification. False-positive observations in studies of rare species may cause an overestimation of the distribution or abundance of the species and distort trend indices. We illustrate this issue with the monitoring of the Eurasian lynx in the Alps. We developed a three-level classification of field records according to their reliability as inferred from whether they were validated or not. The first category (C1) represents 'hard fact' data (e.g. dead lynx); the second category (C2) includes confirmed data (e.g. tracks verified by an expert); and the third category (C3) are unconfirmed data (e.g. any kind of direct visual observation). For lynx, which is a comparatively well-known species in the Alps, we use site-occupancy modelling to estimate its distribution and show that the inferred lynx distribution is highly sensitive to presence sign category: it is larger if based on C3 records compared with the more reliable C1 and C2 records. We believe that the reason for this is a fairly high frequency of false-positive errors among C3 records. This suggests that distribution records for many lesser-known species may be similarly unreliable, because they are mostly or exclusively based on unconfirmed and thus soft data. Nevertheless, such soft data form a considerable part of species assessments as presented, for example in the International Union for Conservation of Nature Red List. However, C3 records can often not be discarded because they may be the only information available. When inferring the distribution of rare carnivores, especially for species with an expanding or shrinking range, we recommend a rigorous discrimination between fully reliable and un- or only partly reliable data, in order to identify possible methodological problems in the distribution maps related to false-positive records. © 2011 The Authors. Animal Conservation © 2011 The Zoological Society of London.

Sturm T.,Slovenia Forest Service | Fernandes P.M.,University of Trás os Montes e Alto Douro
European Journal of Forest Research | Year: 2012

The Canadian fire weather index system (CFFWIS) has been adopted for fire danger rating throughout Europe as part of the European Forest Fire Information System. However, its performance has not been thoroughly assessed, especially in environments less prone to fire. In this study, we characterised fire activity between 1995 and 2009 in the sub-Mediterranean Karst forest management area of SW Slovenia. Five fire danger classes (very low, low, moderate, high and very high) were derived from percentile analysis of the CFFWIS Fire Weather Index. These classes were found to be related with fire activity descriptors. Logistic regression prediction of fire-days based on CFFWIS indices had low accuracy, and better discrimination was achieved by classification tree modelling. Fire activity was found to be driven by current weather conditions rather than by drought. Our findings highlight the potential of fire danger rating to guide fire management but also the limitations imposed by relatively low incidence of fire and the spatial scale of analysis. © 2011 Springer-Verlag.

Elfstrom M.,Norwegian University of Life Sciences | Zedrosser A.,Telemark University College | Zedrosser A.,University of Natural Resources and Life Sciences, Vienna | Jerina K.,University of Ljubljana | And 7 more authors.
Journal of Wildlife Management | Year: 2014

Bears foraging near human developments are often presumed to be responding to food shortage, but this explanation ignores social factors, in particular despotism in bears. We analyzed the age distribution and body condition index (BCI) of shot brown bears in relation to densities of bears and people, and whether the shot bears were killed by managers (i.e., problem bears; n=149), in self-defense (n=51), or were hunter-killed nonproblem bears (n=1,896) during 1990-2010. We compared patterns between areas with (Slovenia) and without supplemental feeding (Sweden) of bears relative to 2 hypotheses. The food-search/food-competition hypothesis predicts that problem bears should have a higher BCI (e.g., exploiting easily accessible and/or nutritious human-derived foods) or lower BCI (e.g., because of food shortage) than nonproblem bears, that BCI and human density should have a positive correlation, and problem bear occurrence and seasonal mean BCI of nonproblem bears should have a negative correlation (i.e., more problem bears during years of low food availability). Food competition among bears additionally predicts an inverse relationship between BCI and bear density. The safety-search/naivety hypothesis (i.e., avoiding other bears or lack of human experience) predicts no relationship between BCI and human density, provided no dietary differences due to spatiotemporal habitat use among bears, no relationship between problem bear occurrence and seasonal mean BCI of nonproblem bears, and does not necessarily predict a difference between BCI for problem/nonproblem bears. If food competition or predation avoidance explained bear occurrence near settlements, we predicted younger problem than nonproblem bears and a negative correlation between age and human density. However, if only food search explained bear occurrence near settlements, we predicted no relation between age and problem or nonproblem bear status, or between age and human density. We found no difference in BCI or its variability between problem and nonproblem bears, no relation between BCI and human density, and no correlation between numbers of problem bears shot and seasonal mean BCI for either country. The peak of shot problem bears occurred from April to June in Slovenia and in June in Sweden (i.e., during the mating period when most intraspecific predation occurs and before fall hyperphagia). Problem bears were younger than nonproblem bears, and both problem and nonproblem bears were younger in areas of higher human density. These age differences, in combination with similarities in BCI between problem and nonproblem bears and lack of correlation between BCI and human density, suggested safety-search and naïve dispersal to be the primary mechanisms responsible for bear occurrence near settlements. Younger bears are less competitive, more vulnerable to intraspecific predation, and lack human experience, compared to adults. Body condition was inversely related to the bear density index in Sweden, whereas we found no correlation in Slovenia, suggesting that supplemental feeding may have reduced food competition, in combination with high bear harvest rates. Bears shot in self-defense were older and their BCI did not differ from that of nonproblem bears. Reasons other than food shortage apparently explained why most bears were involved in encounters with people or viewed as problematic near settlements in our study. © 2014 The Wildlife Society. © 2014 The Authors. Journal of Wildlife Management Published by The Wildlife Society.

Guthlin D.,Ludwig Maximilians University of Munich | Guthlin D.,Albert Ludwigs University of Freiburg | Knauer F.,Albert Ludwigs University of Freiburg | Knauer F.,University of Veterinary Medicine Vienna | And 8 more authors.
Biological Conservation | Year: 2011

According to the Habitats Directive of the European Union, a favorable conservation status for the brown bear (Ursus arctos) should be targeted at the population level in large contiguous habitats such as the Alps, the largest mountain range in Europe. However, in most of the Alps brown bears are extinct and habitat suitability in these areas is often questionable. For this paper, radio-tracking data from four projects with 42 individual bears was compiled to assess habitat suitability. Discrete-choice models with random bear effects were fitted and compared to results obtained from compositional analysis and logistic regression. Sound definition of the available area in the discrete-choice model turned out to be essential. Brown bears showed a preference for forested and steep habitats and an avoidance of roads.Results from the three approaches were used to predict habitat suitability across the entire range of the Eastern Alps. Minimum potential population size was projected based on observed densities in Trentino and Central Austria, and ranged from 1228 to 1625 individuals, with 518-686 mature bears. This would satisfy a favorable conservation status. The developed methodology also has wide applicability to quantification of habitat suitability and potential population size in other cases where species are at risk. © 2011 Elsevier Ltd.

Kaczensky P.,University of Veterinary Medicine Vienna | Jerina K.,University of Ljubljana | Jonozovic M.,Slovenia Forest Service | Krofel M.,University of Ljubljana | And 4 more authors.
Ursus | Year: 2011

Illegal killings are a major threat to wildlife conservation worldwide. Combating illegal killings and understanding the motives behind them are among the top challenges for the conservation of controversial species such as large carnivores. In Europe, the Eastern Alps are a focal area for many active brown bear (Ursus arctos) conservation and restoration projects. The wider public generally has a positive attitude toward bears and bear restoration, but some hunters and farmers seem less supportive. The extent this opposition can reach was demonstrated by the well documented illegal killing of a bear in the three-country triangle of Slovenia, Italy, and Austria in June 2009. We provide detailed background information and discuss this case within the context of the lack of a northward expansion of the Dinaric-Pindos bear population and the failed bear re-introduction in central Austria. © 2011 International Association for Bear Research and Management.

Krc J.,Vecna pot | Begus J.,Slovenia Forest Service
Croatian Journal of Forest Engineering | Year: 2013

The article presents the model for determining inaccessible forest areas by density of forest roads. The model is based on the GIS analysis of the distances between the existing network of public and forest roads and inaccessible forest areas, sizes of excluded forest areas, and forest site potentials. In order to increase forest road density, the following must be done: (1) construct connecting roads to the inaccessible forest areas and (2) construct new forest roads with different density in the excluded inaccessible forest areas. The model provides the minimum size of the inaccessible area located at least 300 m away from the existing forest and public road. The selected inaccessible forest areas are first analyzed according to their size - plot size of at least 30 ha is used as a model default size suitable for economically justified construction of the access road that connects the existing road network to the inaccessible forest area. The analysis showed that there are still 210,385 ha of inaccessible forests in Slovenia according to the model criteria. According to the research of regional units conducted by forest experts and based on the determination of priorities for the next ten-year forest management plan, the construction of 758 km of new forest roads is planned at the national level.

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