Category: Blog EN

The fieldwork season began this spring. The teams of the Swiss Ornithological Institute started earliest at the beginning of April in Ticino and Graubünden. Since then, 117 yellowhammers have been caught, sampled and released throughout Switzerland. Breeding calls of natterjack toads began at the end of April, a sign for which the staff of the karch had been waiting to begin sampling. However, the search for natterjack toad populations at the planned collection sites have not always been successful and often the collection sites planned as reserves needed to be used. This was due to characteristics of the natterjack toad’s pioneer habitat, which is composed primarily of temporary pools in gravel pits and floodplains, which are not stable long-term. The input of the karch staff, with their knowledge of local natterjack toad spawning areas and ecology, has been invaluable. Thanks to them, spawning areas that are no longer active could be removed from the list of collection sites in advance, and new collection sites could be recorded where necessary. Sampling of the populations of the Carthusian pink and the Hare’s-tail cottongrass has also started. Lastly, depending on the weather, sampling of the False heath fritillary will soon begin. We are curious to see what challenges this particular sampling holds for our experts.

Historical genetic diversity will be investigated for the Hare’s-tail cottongrass (Eriophorum vaginatum) and the Valerian Fritillary (Melitaea diamina). For this purpose, we have reached out to numerous museums and herbaria about whether their collections contain specimens of these two species that are at least 50 years old. We found 767 vouchers of the Hare’s-tail cottongrass and about 1’400 vouchers of the Valerian Fritillary that are eligible for our investigation, which requires the removal of a small piece of tissue. Important in the selection of individuals to be sequenced from the collections is now where the two species were collected in the past and at which frequency. In order to obtain the relevant geographical information, these specimens have to be georeferenced using old handwritten labels (see pictures). A polygon is defined where the specimens were originally collected, based on the locations on the labels. The coordinates are archived in a database, which serves as a basis for sample selection. The example of Eriophorum from 1907 shows how much the landscape has changed and the habitats had to give way to settlements.

The tissue samples for creating the reference genomes of the five species have arrived in the laboratory. The reference genome contains the entire hereditary information of an individual (DNA). It is needed to later visualise the genetic differences between different individuals of a species. In the laboratory, different extraction methods are currently being tested for the natterjack toad, the valerian fritillary and the yellowhammer. To create a genome with as few gaps as possible, DNA fragments of maximum length are needed.

A strategy for collecting samples from the five study species will be designed. A random selection of collection sites is aimed at in order to ensure comparability between species. Using information on the distribution of the species from the InfoSpecies databases and other sources, the distribution throughout Switzerland is outlined. From this, the collection points can be randomly selected, for example.