By Faye Whiley
PhD Candidate in the School of Anthropology and Conservation, DICE, at the University of Kent.
Twitter: @FayeWhiley Instagram: @theconservationdiaries
After the annual wolf hunting quota in Slovakia, major inconsistencies in numbers were reported. Environmentalists stated approximately 150 wolves remained, whilst the game statistics reported over two thousand wolves remained. This highlighted an important need for an objective method to measure wolf numbers. The Slovak Wildlife Society (http://www.slovakwildlife.org/) established a project in the Tatra Mountains to estimate and track large carnivore populations every winter.
A non-invasive genetic sampling method is employed to estimate the population numbers by collecting fresh urine, faecal and hair samples. These samples are sent to an external laboratory for genetic analysis. The genetic analysis results in an estimation of wolf individuals and wolf pack numbers. Faecal samples were also collected for diet analysis, which provides insight into the predator-prey relationship within the area. Last winter, with a group of volunteers, I had the opportunity to collect samples for genetic analysis.
For three weeks we tracked large carnivores to collect samples. Each morning we ate breakfast at 6 am and organised the groups for the transects that day. Transects are set walking routes of distances between 12 – 20 km and vary in levels of difficulty depending on the elevation, weather conditions and tracks found (wolves are your best personal trainers!). The snow depth reached 85 cm in the final week, and we needed snowshoes whilst following the transects.
After collecting the equipment required for the day, we set off in groups. We recorded the transect and locations of samples on the GPS. We also noted large carnivore prints and prints from other species. Large carnivore prints recorded were wolf (Canis lupus lupus) and Eurasian lynx (Lynx lynx). Brown bears (Ursus arctos arctos) hibernate in winter (Rigg & Adamec 2007), but we did find bear faeces! Other species identified on our transects included red deer (Cervus elaphus), roe deer (Capreolus capreolus), brown hare (Lepus europaeus), red squirrel (Sciurus vulgaris) and wildcat (Felis silvestris). We backtracked any tracks we found to search for samples. Backtracking requires following the tracks in the opposite direction the animal was heading. We were looking to collect fresh samples (1 – 2 days old) of faeces, hair, and urine (Fig. 1). In the evenings, we inputted the data from the day into the computer and uploaded our photographs. After dinner, each group presented their daily findings.
Collecting a wolf urine sample for genetic analysis in the Tatra Mountains, Slovakia
After walking most routes, we returned to the same transects after an interval of time with the aim of collecting further samples. This method is called the mark-recapture analysis and involves identifying individuals and re-identifying them (Ogutu et al. 2006). In a previous year, this method estimated 20 – 45 individual wolves in at least five packs with an average pack size of five individuals (Rigg et al. 2014). The samples and data collected over the three weeks were sent to an external laboratory for analysis to calculate the number of wolf individuals and the number of wolf packs. These findings are presented at an annual meeting with the Ministry of Agriculture to influence the annual hunting quota of wolves. Over recent months, no annual quota for wolf hunting was set which means it is currently illegal to shoot any wolves in Slovakia. The Slovak Wildlife Society will continue to monitor the wolf populations and it will be interesting to observe how the wolf population numbers are affected by the removal of legal hunting.
References:
Ogutu JO, Piepho HP, Dublin HT, Reid RS, Bhola N (2006) Application of mark–recapture methods to lions: satisfying assumptions by using covariates to explain heterogeneity. Journal of Zoology 269: 161-174. https://doi.org/10.1111/j.1469-7998.2006.00058.x
Rigg R, Adamec M (2007) Status, ecology, and management of the brown bear (Ursus arctos) in Slovakia. Slovak Wildlife Society, Liptovský Hrádok, 128. http://www.medvede.sk/pdf/BEARS_status_Slovakia_2007.pdf
Rigg R, Skrbinšek T, Linnell J (2014) A pilot study of wolves in Slovakia using noninvasive genetic sampling. http://slovakwildlife.org/pdf/pa_slovakia_finalreport.pd