Nature conservation with large herbivores in a restored riparian environment

Restoring damaged or destructed ecosystems became an urgent target for nature conservation of the twenty-first century. Achieving and maintaining habitat diversity is generally the aim in ecosystem restoration, especially in projects associated with rewilding, and large herbivores are important actors in this process due to their role as ecosystem engineers. The influence that large herbivores have on different parts of the ecosystem are, however, not straightforward. In this thesis, I investigated how birds, as indicator species of biodiversity, may be affected by large herbivores in a recently restored floodplain ecosystem on the Rhine Island of the national nature reserve Petite Camargue Alsacienne.
My work focused on how numbers of the most abundant songbird species and of birds of different foraging guilds on the restored area are related to the spatiotemporal distribution of cattle and horses that were introduced to the Rhine Island as ecosystem engineers. I also investigated the historical and political background of choosing certain large herbivores for nature conservation.
The results showed that some bird species, for example the Eurasian Skylark, were more often found at those parts of the grazed area where grazer density was higher. When also the effect of habitat and season were included in the analysis, the results revealed that, among the bird guilds present in the study area, it was the open-area foraging birds that profited most from the year-round low-intensity grazing with cattle and horses. The distribution of wetland- and woodland-associated birds was more clearly related to the habitat than to the distribution of grazers, and aerial-foraging birds seemed to be largely independent from both habitat and grazers, but depended mainly on the season. Overall, the highest numbers of bird species and individuals were found in open areas scattered with woody patches and waterbodies, and in areas with moderate grazer density. The results suggest that, in line with the recommendations of the approach of rewilding, a mosaic of landcover types with low percentages of woody cover maintained by low-intensity grazing fulfils the needs of birds with different feeding ecologies.
Even though grazing by large herbivores is reportedly a suitable tool in the hands of conservationists, the choice of the grazer species and breed often implies difficult decision making. I scrutinized the historical and socio-political background of the origin of Konik horses as a case study in the context of choosing a breed for nature conservation. The review revealed that the origin stories of a so-called European wild horse, the Tarpan, and the Konik being its direct descendent are manmade myths that likely hinder effective conservation management. Breeding practices promoting the myth led to inbreeding of a small population due to the wish of recreating an extinct wild horse, and the practice of inbreeding seems to continue also today. Therefore, even though the marketing of Koniks and other robust breeds as ‘wild’ horses or ‘closest descendants’ of wild horses seems to be attractive, conservation management should not be based on such mythologized origin stories.