The Thuringian Forest – the missing link

After the Eurasian lynx (Lynx lynx) had been extinct in Central Europe for about 200 years, there have been lynx reintroduction projects in many European countries since the 1970s. Many of these projects have succeeded in bringing Europe’s largest predatory cat back into suitable forest areas. However, decades after the first reintroductions, lynx still occur in isolated populations. This spatial isolation has led to a loss of genetic diversity in most populations, which threatens the long-term survival of these populations. The connection of isolated European lynx populations has therefore been identified as a key objective for the conservation of lynx in Europe.

A total of around 130 independent lynx live in Germany, most of which are distributed over three distribution areas: The Bavarian Forest, the Harz Mountains, and the Palatinate Forest. However, all three regions are at least 250 km apart and also widely isolated from other European lynx occurrences. Between the three distribution areas, lynx do not yet occur permanently despite potentially suitable habitat. Consequently, there is no exchange of individuals between the three populations. The situation of the lynx in Germany is therefore far from the goals formulated in the National Strategy on Biological Diversity, according to which the lynx should once again be present throughout Germany’s Alps and low mountain ranges by 2020.

Due to its central location, the Free State of Thuringia is of outstanding importance for the connection of the isolated German lynx populations. In particular, the approximately 2,200 km² forest area of the Thuringian Forest would provide a suitable habitat over a large area, where it is estimated that up to 60 independent lynx could live. A stable population core in the Thuringian Forest would be the missing link to connect the populations in the Harz Mountains and the Bavarian Forest/Bohemian Forest.

However, even 20 years after the reintroduction of lynx in the Harz Mountains (and 30 years after the reintroduction of lynx in the Bavarian Forest/Bohemian Forest), the species has not yet found a permanent home in the Thuringian Forest. A dispersal model developed on behalf of BUND Thuringia also suggests that natural colonisation of the Thuringian Forest is not to be expected in the next 20-30 years either.

However, the model also shows that the active introduction of 12-20 lynx into the Thuringian Forest could create a sufficiently large and stable population core through which the populations in the Harz Mountains and the Bavarian Forest would be brought into contact with each other. According to the model’s predictions, starting from the Thuringian Forest, the lynx would also open up further suitable habitats in Central Germany (e.g. Erzgebirge, Rhön, Spessart, North Hessian Highlands).

A one-time introduction of 12-20 lynx into the Thuringian Forest would thus create a connected central German metapopulation, which in the long term would reach a size where the loss of genetic diversity would be negligible. 

Project activities

When establishing new lynx populations, it is important to ensure that the founder population (approx. 20 animals) is genetically as diverse as possible. In order to achieve the goal of a gene pool that is as broad as possible, lynx of different origins are therefore to be released in the Thuringian Forest:

Wild-caught lynx

About half of the animals for the founder population in the Thuringian Forest will be wild lynx captured in Romania. To prevent too close a relationship and thus possible inbreeding problems, the lynxes are captured in four different regions.

Captive bred lynx from enclosures

The European Association of Zoos and Aquaria (EAZA) has a studbook programme for the Carpathian lynx. Since the relationships and genetics of the lynx kept in the studbook are known, lynx can be selectively mated without fear of inbreeding.  While in the past the main focus was on the need for young lynx for their own enclosures, in future lynx will also be bred specifically for release into the wild in field projects. Protocols and guidelines for the use of enclosure animals for field projects are currently being developed by the international Linking Lynx group. These animals grow up under special conditions and are specifically prepared for life in the wild. In Thuringia, this is done in a lynx coordination enclosure in the wild cat village Hütscheroda, which was built especially for this purpose.

Regardless of their origin, the lynx spend a few weeks in a so-called “soft release enclosure” in the middle of the Thuringian Forest before their release. The aim of this enclosure is to slowly acclimatise the lynxes to their new environment. Especially with wild lynx, it is known that some animals undertake large migrations after a “hard-release”, i.e. release from a box directly after transport from their place of origin, instead of remaining in their intended target area. This effect should be avoided with the soft-release approach. Since the enclosure can be divided into two compartments, there is also the possibility that two lynx of different sexes can be kept at the same time and can get to know each other. After a period of about four weeks, during which the animals are still provided with water and game, the gate is then opened and the lynxes are free.

In order to obtain information about where the lynxes are and where they establish their territories, all animals are equipped with GPS collars. It is even possible to identify kills or litter sites using the data.

The collar transmitters do not restrict the lynx in their living and hunting habits. They are also equipped with predetermined breaking points so that they fall off by themselves after about a year. In order to obtain additional information about migrating lynx and newborn cubs, the newly emerging population will also be monitored by photo traps and so-called genetic monitoring.