Genetic research of wolves

During 2011, the Faculty of Veterinary Medicine of the University of Zagreb, in cooperation with the Laboratorio di Genetica ISPRA in Italy conducted initial analyses of 150 tissue samples for 12 microsatellites for wolves from Croatia and Italy. The research is still ongoing and results have not yet been published.

In the research on the existence of cross-breeds, a total of 203 different animals were examined and grouped into three categories based on their phenotype: wolf, dog and suspected cross-breed. Of the 10 suspected cross-breeds, only 3 were confirmed as such, while the remainder were wolves. In the group of wolves, an addition two cross-breeds were found, though their external properties (phenotype) corresponded to the true wolves. All five cross-breeds from nature were cross-breeds from the combination female wolf and dog, while one cross-breed from captivity was the cross of a wolf and bitch.

Of the five cross-breeds from nature, four were from Dalmatia and one from Lika.

The appearance of cross-breeds (3%) in Croatia, and particularly in Dalmatia, warns of the eroded social structure of that part of the wolf population in Croatia. The high mortality rate also has the consequence of a high “turnover” of individuals in the population, with the constant break-down and formation of packs and the lack of true partners for the formation of packs. There are also a significant number of dogs in the same area, which results in the creation of cross-breeds. Due to a lack of partners, wolves can mate not only with dogs, but also with relatives (brother-sister, parent-offspring), and the result can be anomalies such as the albinism recorded in the Mosor pack.

During 2012 (end of June), another 51 samples of wolf tissue were collected for genetic analyses. Genotypisation of mitochondrial DNA (mtDNA) was performed in Croatia, while cell DNA (microsatellites) were analysed in Italy and Slovenia. The results of these analyses will be compiled and interpreted with previous data and will serve for analysis of the population and comparison of the Dinaric and Apennine wolf populations, and to determine the degree of hybridisation between wolves and dogs in the Dinaric population. Analyses are still underway.

The research results conducted by a team of experts within the LIFE+ SloWolf project have provided the most objective insight into the cross-border dynamics of the Croatian wolf population. Namely, as part of that project, monitoring of the state of the wolf population in Slovenia, including genetic analysis, is regularly conducted. A part of the laboratory materials for the processing of DNA materials was procured by the State Institute for Nature Protection during 2011/2012, and by the Faculty of Veterinary Medicine during 2012/2013, while the experts from the Faculty of Biotechnology of the University of Ljubljana in return volunteered to process the samples collected in Croatia by large carnivore researchers from the Faculty of Veterinary Medicine.

The first season for collecting samples for genetic research 2010/2011 took place during the period from 26 June 2010 to 30 June 2011, and the second season 2011/2012 from 1 July 2011 to 30 June 2012, in which significant efforts were invested in sample collection, with more than a hundred people participating. The results of the third season 2012/2013, for which samples were collected in the period from 30 June 2012 to 1 July 2013 will be processed by the end of 2013.

In the first season, 571 samples were collected (145 saliva samples, 117 urine samples and 309 faeces samples). Of these 53 samples were from the Gorski Kotar region. A total of 449 non-invasive genetic samples were analysed. The analysis also included tissue samples from 12 individuals of perished wolves. In the second season, a total of 544 samples were collected and processed (191 faeces samples (of which 28 from Gorski Kotar), 98 urine samples and 257 saliva samples. The analysis also included tissue samples of 11 wolves that perished.

Estimates of abundance were conducted separately for each monitoring season, and for each season, two assessments were given – real and extrapolated – due to the dynamics of natality and mortality in packs. The real estimate was given for the month October, when the young from the current year were easier to determine based on their greater mobility. The extrapolated assessment was given for the month March when the period of legal culling is completed, and there are not yet young. The analysis included samples from Gorski Kotar, with areas of crossborder packs that inhabit Slovenia and Croatia, which enabled better estimates.

In October 2010, a total of 49 wolf individuals (95% confidence interval 43 to 58) were determined in the areas of Slovenia and Gorski Kotar. Considering the location where the samples of recognised individuals were found, it was assessed that of that number, 18 individuals live in cross-border packs; with half the individuals (9) counted within the Slovenian population and half (9) in Croatia. The total abundance was assessed only for the territory of Slovenia. As such, it was estimated in autumn 2010 that 41 wolves inhabited the territory of Slovenia (35–50, 95% CI). When the recorded mortality was subtracted (first season 13 individuals – 12 in Slovenia and 1 in Gorski Kotar), it was assessed that in March 2011 there were 37 wolf individuals in the entire sample collection area (31–46; 95% CI), or 31 individuals in the territory of Slovenia (25–40; 95% CI).

For the second season, the assessment was conducted in the same way. In October 2011, a total of 47 wolf individuals (44 – 51; 95% CI) inhabited the sample collection area, with 41 individuals only in the Slovenian population (38–45; 95% CI). When the recorded mortality was subtracted (in the second season 11 individuals – 10 in Slovenia and 1 in Gorski Kotar), it was assessed that in March 2012, there were 35 wolf individuals (28–35; 95% CI) in the entire sampling area. Preliminary analyses of relations among individuals are currently underway.