A main challenge in monitoring large carnivores is the spatial extent of the population that often extend over several countries. The large size of the area does not allow all areas to be monitored with the same intensity.
Monitoring activities and sampling design
No single method is able to respond to all the mentioned parameters. Therefore a combination of monitoring methods is used evaluate the status of a population.
Collection of chance observations
Data collection by means of citizen science is highly effective. Thousands of people are spending time in the forests per day. It is only logical that every so often a lynx (or a sign of a lynx) is seen by a citizen. Many people are highly motivated to report their findings, e.g. seeing a lynx is an emotional event. The project team needs to make sure that citizens know where to report to (webportal, geodatabase). If quick reporting is assured, chance observations can be used to gather additional monitoring data: lynx tracks can be followed by members of the monitoring network in order to find a genetic sample (scat, urine), or a camera trap can be placed at prey remains in order to identify the lynx individual if it comes back.
The collection of chance observations is an efficient and cost-effective tool with which the whole distribution area can and should be covered. This method must be applied even in areas where more sophisticated monitoring methods are in place to allow calibration and extrapolation from one area with high monitoring effort to low effort areas.
A special case of chance observations is the finding of a dead lynx. An autopsy should always aim to determine the cause of death. This is also part of conflict monitoring in the case of illegal killings.
Camera traps have become very popular to monitor wildlife. They provide the best results for species that have individual marks, e.g. lynx. Lynx pictures are collected by means of camera traps installed in the frame of research projects, or by managers, hunters, naturalists. Occasionally photos are also made by chance.
Choice of season: For both occupancy as well as capture recapture studies it is necessary that the population is “closed”, e.g. no birth, death, immigration, emigration. This means that ideally sampling should take place outside of birth season, outside dispersal season and outside the season when most mortality occurs. Therefore May and June can be excluded due to birth. Separation from the mother can start already during rutting season but has a peak in April. Dispersal is usually finished by the end of October. Since lynx are not hunted in the Dinaric-SE Alpine population there is no peak in mortality. The best season for camera trapping can be defined as from October to April. Winter is also a good season for camera trapping because lynx can be guided to walk in front of the camera trap through preparing a path in the snow. A higher chance to get lynx photos is also given during the rutting season due to higher mobility of the lynx.
Genetic monitoring allows to answer a high spectrum of questions, from the individual to population level. Every chance should be taken to collect genetic samples: following tracks in the snow to find urine or scat, take saliva samples from prey remains, search around prey remains for scats, hair traps, blood samples at captures, tissue samples from dead animals.
Snow tracking is a coordinated, systematic search for lynx tracks to count lynx. Ideally a transect follows a forest road from the bottom of the valley up to the mountain ridge in order to cross a lynx track. The lynx track should be followed (in both directions) to find a genetic sample. (Presuming that the field crew is experienced enough to judge the risk of e.g. avalanches etc.) Complete snow cover is a prerequisite of snow tracking, which is done 48 hours +- 24 hours after snowfall. This gives the animals enough time to move, but avoids that the tracks become too “chaotic”. Ideal is the first snow of the winter as the snow depth is lower.