The size of Finland’s lynx population is assessed on the basis of observations made between 1 September and 28 February (29 February) reported by large-carnivore contact persons. Also separate field counts of tracks left by lynxes on snow, as well as research projects launched by Luke, generate data enabling the assessment of the population size.
To determine the size of the population, the number of individual litters recorded is eatimated from the observational data. Number of litters is then multiplied by species and area specific coefficients. Such an coefficient describes the proportion of litters in relation to the total number of individual lynxes in an area (for example, ‘5’ indicates that, in terms of calculation, for each specified litter there are all together five individuals within the area.) The proportion of litters out of the total number of individuals varies depending on the developmental phase of a lynx population (establishing population or a population that has already established its presence); consequently, the coefficient varies between areas.
Assessing the number of individuals for a small area would be neither sensible nor possible. Sub-assessments are impossible on the level of individual municipalities. Sub-assessments currently reflect the administrative division of the regional offices of the Finnish Wildlife Agency.
The assessment method is based on Nordic studies of lynx behaviour and biology, and has been adapted to the Finnish conditions in which random observations of litters are distributed over a long period of time. This method enables an assessment of the minimum size of the population. In a case results of separate counts are available in addition to random observations, this method enables assessment of the population’s average size. Continuous efforts are being made to fine-tune the assessment method based on research results.
Separate field counts make population size assessment more accurate
The number of large carnivores can be ascertained by performing extensive, one-off counts in the field and repeating them in various areas in different years. Such counts are based on collaboration between Luke, the Finnish Wildlife Agency and voluntary hunters, and other nature enthusiasts.
With more than a thousand people seeking the tracks left by lynxes with-in a single province on a single day, practically all tracks can be spotted. Naturally, this requires careful tracking to ensure that the trackers do not become confused between tracks left by different individuals or species.
Predictive modelling helps the managers to decide on the size of the hunting quota.
Luke has developed a predictive population model to aid the population management in decision-making. This model predicts how different hunting quotas will impact on the development of the lynx population in a four year timeline. In practice, the model provides three alternative hunting rates producing an increasing, decreasing or a stable population. This model was used for the first time in 2012 and it is updated annually with the most recent data.
Photo on top of the page: Vastavalo