National and regional story (Slovenia) - A Bear’s tale

Estimates of brown bear numbers in Slovenia

In most of central and southern Europe, the number of bears fell considerably at the end of the 19th century, and they disappeared completely disappeared from some areas. Today the attitude of people to these wild animals has changed. Therefore, in various parts of Europe, great efforts have been made to preserve bear populations. In 1999 and 2002, ten bears were captured and taken to Italy, to the area of the Adamello Brenta Park. Under an agreement between Slovenia and France, five bears were relocated from Slovenia to the Pyrenees in 2006.

The basis for the management of the bear population is expert knowledge of the biology and ecology of the species (behaviour, feeding characteristics, etc.), as well as of species numbers and relationship to human beings. Two studies were completed at the Environmental Agency of the Republic of Slovenia in 2008 which, using new methods, provided a large amount of basic information about this charismatic species, including an estimate of the bear population in Slovenia.

Previous estimates of the bear population had been based on figures drawn up as a result of observation of bears at permanent counting locations three times a year. According to these estimates, there were between 500 and 700 bears in Slovenia in 2007. The new estimates of population numbers have been obtained using newer methods - i.e. on the basis of age as determined by grinding the teeth of bears taken from the wild and of genetic molecular research.

In the study entitled Analysis of Brown Bears Taken from the Wild in Slovenia 2003-2006 on the Basis of Age Determined by Teeth-Grinding (Jerina and Adamič, 2007), the teeth of 326 bears culled over this period were examined. The analysis was supplemented by data on the age of a further 369 animals taken from the wild before 2003. By examining the age and sex of culled animals, it is possible, on the basis of certain assumptions, to ascertain a number of population characteristics, such as the sex and age composition of the population, its minimum fertility, its abundance, etc. The results of research into population abundance show that there were around 290 bears in 1998, with this number gradually rising to an estimated 370 in 2006. This was followed by another fall to an estimated 320 bears in 2008. In the opinion of researchers, the reason for the growth in the estimated population numbers is high fertility, and partly also the inflow of bears from the Croatian population. The research also points out that, in light of the reduction in population numbers in recent years, the culling of the brown bear must be scaled back accordingly in order to prevent a drop in the population in Slovenia.

A total of 1 057 non-invasive samples (i.e. primarily droppings and some hair samples) were collected for the study entitled Analysis of Bears Taken from the Wild and Genetic-Molecular Research into the Bear Population in Slovenia (Kos et al, 2008). These samples were used to determine the bears' genotype. A total of 354 different bears were identified (159 males, 195 females), which means that there were at least this many bears in Slovenia at the end of 2007. On the basis of these numbers, a method of modelling the capture-marking-recapture for the entire bear population area was used to draw up an estimate of abundance. This estimate, with a 95 % degree of certainty, stood at between 394 and 475 brown bears.

The majority of the bears lived in Javorniki, Snežnik, Menišija, Velika Gora, Goteniška Gora and Mala Gora. Their presence here is expected because of the exceptional crop of beech during the sampling period. The population in the area west of the Ljubljana-Koper motorway was somewhat lower than expected, demonstrating the negative impact of the motorway as a significant demographic barrier.

According to research estimates, the Slovenian part of the brown bear population is in a good state in terms of both numbers and genetic diversity. One statistic does give cause for concern, however: over 80 % of the bears do not reach four years of age, which demonstrates the considerable threats faced by young bears.

The studies mentioned above contain the most reliable results produced so far, constituting the best estimate of the Slovenian bear population. Since the population constantly changes over time, partly as a result of movements across the border with Croatia, it is impossible to arrive at a precise number and it would be erroneous to talk of precision at all.