At home on foreign meadows: the reintroduction of two Maculinea butterfly species

Maculinea butterflies live as obligate parasites of specific Myrmica host ants in meadow and heathland habitat maintained by low intensity landuse. Changes in agriculture caused the decline and extinction of many populations. In The Netherlands, Maculinea nausithous and M. teleius disappeared in the 1970s. In 1990, they were reintroduced following the recommendations of the IUCN. This study focuses on the evaluation of this reintroduction into the nature reserve Moerputten in the province of Northern Brabant. Population establishment and dispersal were monitored and accompanied by research on the impact of the reintroduction on species-specific genetic composition and behaviour. Maculinea teleius immediately established itself on one meadow, where the population still occurs today. Maculinea nausithous , being the more mobile species, colonized habitat patches with the specific host ant at higher distances. Three subpopulations were founded.At the small spatial scale the females of both species were able to select habitat patches with host plants and host ants to deposit their eggs, rather then loosing many offspring by random oviposition. At the ladscape scale the occurence of the populations was also strongly related to the presence of the specific host ant species. However, through the limited dispersal capacity of the adults high quality patches at greater distance remain uncolonized. Genetic analysis showed that the new populations have not experienced a bottleneck in numbers following the translocation. However, the populations experienced selection due to changed ecological conditions at the founder site, but ecologically relevant traits were apparently not affected.The conservation of the reintroduced population should concentrate on keeping a high habitat quality on the colonized sites and enabling the development of metapopulations by improving the management of potential sites within colonization distance. Ultimately, the persistence of the populations depends on the availability of an extensive network of suitable habitat patches. This requires conservation management at a landscape scale. This study emphasizes that a carefully planned and implemented reintroduction can be a successful tool for species conservation if both small and large spatial scales are taken into account