Genetisch onderzoek vitaliteit en authenticiteit vroedmeesterpad in Limburg

Genetic research common midwife toad Limburg The common midwife toad (Alytes obstetricans) occurs only naturally in the outermost southeastern parts of the Netherlands (Zuid-Limburg), which demarcates the northwestern limit of its distribution range in Europe. Here, the once connected populations are nowadays highly fragmented and isolated, with low levels of adult animals in some populations. This may have led to genetic erosion and a reduced fitness of the remaining populations. In 2019, a genetic study was undertaken to provide insight in these factors. Of the 12 included populations, two (Schaelsberg and ENCI-groeve) were clearly non-native, likely originating from Central-France and even more southern regions, respectively. The genetic diversity was relatively low in the native populations. However, it was comparable to other populations along the northern distribution limit in Belgium and Germany. Furthermore, the expected heterozygosity (expressed as FIS) was comparable in relatively large and small populations. This indicates that other factors, such as habitat suitability and potentially also amphibian diseases, may have a larger e*ect on the population size and viability than genetic erosion has. Nevertheless, natural connections and exchange of animals between native populations are crucial for the long-term survival of the common midwife toad in the Netherlands. In contrast, illegally introduced (non-native) populations need to be isolated or even removed and new introductions need to be prevented, to minimize the potentially detrimental e*ects on native populations, such as loss of local genetic diversity, disruption of the ecosystem, and introduction of amphibian pathogens. In Nederland komt de vroedmeesterpad van oorsprong alleen voor in het Zuid-Limburgse heuvelland. Veel populaties zijn hier echter sterk gefragmenteerd en geïsoleerd, met veelal lage aantallen geslachtsrijpe dieren. Dit kan mogelijk leiden tot genetische verarming en uiteindelijk invloed hebben op de duurzame staat van instandhouding van de soort in Limburg. Daarnaast hebben sommige populaties mogelijk een uitheemse herkomst. Om hier meer inzicht in te krijgen, is in 2019 een genetisch onderzoek uitgevoerd in opdracht van de provincie Limburg.