Genetic monitoring 2007

In 2007, extensive genetic monitoring of brown bears was carried out in Slovenia for the first time, with the main objective of obtaining a reliable estimate of the population size and establishing a solid scientific basis for the long-term management of this species. The study was based on non-invasive genetic methods, which at the time represented a modern and internationally comparable approach to monitoring large carnivores.

A key part of the monitoring was the systematic collection of bear genetic samples, mainly feces, which took place from September to December 2007. A large number of hunters, foresters, and other participants throughout the entire area of permanent bear presence in Slovenia were involved in the collection of samples. A total of 1,057 non-invasive samples were collected in 84 days, which enabled very good spatial coverage of the area and high reliability of further analyses.

Laboratory analyses were carried out between October 2007 and September 2008. Of all the non-invasive samples collected, 88% were successfully genotyped, which is an exceptionally good result for this type of research. In addition to non-invasive samples, tissue samples from bears that died during sampling or were removed from the wild were also included in the analysis. Based on genetic analyses, 354 different brown bears were identified in the entire sample, of which 195 were females (55%), and 159 were males (45%). On average, each individual bear was detected 2.7 times, indicating high sampling intensity and success.

To estimate the total population size, researchers used the capture-mark-recapture (CMR) method, which includes the effects of mortality and animal movements outside the sampling area. The final results showed that at the end of sampling, i.e., at the end of 2007, there were an estimated 434 brown bears in Slovenia. The 95% confidence interval was 394–475 individuals. This is an estimate of the so-called current population at the end of sampling, which already takes into account all known bear mortality during the study. This estimate represents the lowest annual (autumn) population size, just before the winter period and before the arrival of a new generation of cubs in the following year.

The monitoring results also showed differences in the density and distribution of bears across different parts of Slovenia, which were partly related to the availability of food and the spatial characteristics of individual areas. Nevertheless, the authors of the study assessed that the overall estimate reflects the actual population status at the time of sampling very well and is therefore suitable for both management and further modeling of population dynamics.

Genetic monitoring in 2007 represented an important milestone in the monitoring of brown bears in Slovenia. In addition to providing a reliable estimate of population size, it also enabled long-term tracking of individual bears and clearly demonstrated the advantages of non-invasive genetic methods. The results directly contributed to a better understanding of the population and served as a basis for subsequent genetic surveys and the modern management of one of the most prominent wild species in Slovenia.

More about it here.