How can genetic information be used to plan green bridges over motorways more effectively or to prove the presence of a rare species of newt in a pond without any sightings of the animal? Researchers at WSL are using genetics as an effective conservation tool, making the new techniques practical for users.

Rolf Holderegger, member of the WSL directorate. (Photo: Kellenberger Kaminski Photographie)

Motorways dissect the habitats of wild animals. Green bridges are intended to ensure that the animals can move around widely along their traditional routes again. But do these expensive structures really enable this to happen? Direct observations on green bridges prove that deer cross from one side of the motorway to the other, and animals fitted with transmitters show which routes individuals take. But this data capture does not allow conclusions to be drawn as to whether any exchange takes place between populations over large distances.

"Genetics can be used to answer this question," explained Rolf Holderegger, member of the directorate of the Swiss Federal Institute for Forest, Snow and Landscape Research WSL. To do this, the experts analyse samples of deer which have been hunted or run over, as well as droppings. Applying routine genetic methodology, the sort used in medicine, it is possible to determine how the genetic material of individual animals and of entire populations differs. "The more genetically different the populations are, the less exchange there has been," explained Rolf Holderegger summing up. Therefore, genetic patterns can be used to estimate the wide-scale success of green bridges and to improve planning.

"While genetics will not displace other conservation methods, it can provide vital help in solving many problems," says Rolf Holderegger.

"While genetics will not displace other conservation methods, it can provide vital help in solving many problems," pointed out the Head of the WSL research unit on "Biodiversity and Conservation Biology". The new methodology in conservation is still being used chiefly by research institutions, although Rolf Holderegger is convinced that the time has come for the technology to be transferred over to the private sector. WSL is also an academic partner of the CTI "Toolbox for Conservation Genetics" project. Rapperswil University of Applied Science of Technology (HSR) is developing suitable working practices for the application of genetic methodology in conservation within the scope of that project.

On the trail of rare species

The purpose of these practices is to make it easier for the Swiss government and the cantonal authorities, as the principals, to make use of genetic methodology in conservation. WSL is being joined in the project by the University of Zurich, a firm of ecology consultants and a DNA analysis company. "The Swiss government and the cantonal authorities are taking a great interest," said Rolf Holderegger, who has also published a manual on conservation genetics for practical application. One of the modules of the CTI project is geared towards simplified techniques for recognising species in rivers and lakes.

Rolf Holderegger, member of the WSL directorate. (Photo: Kellenberger Kaminski Photographie)

If anyone wished to know which frogs or newts live in a pond, an amphibian specialist used to have to go on repeated observation tours. All it takes now is a small sample of water. It contains the genetic material of all the creatures that live or have died in the pond, including the phlegm and droppings of frogs and newts. The experts filter out fragments of DNA in the lab that are specific to amphibians but which vary from one amphibian species to the next, and they duplicate them. This gives them a list of different DNA fragments which they compare against reference data. They can tell from that which species of amphibians exist in the pond. Rolf Holdenegger explained that "it allows you to prove the presence of rare newts which are very difficult to observe." This barcoding also reveals whether the chytrid fungus, which poses a danger to amphibians, occurs in the pond which is being studied.

Individuals can also be identified from dropping or saliva samples. Genetic fingerprinting reveals which bear was seen in Switzerland, or whether a sheep was mauled by a wolf or a dog. It can also be used to record the population size of rare, timid species, such as the capercaillie. Observers used to have to count the numbers of birds in places where they congregated to mate. Droppings can now be collected within a particular area whether or not it is mating season. It allows you to find out how many individuals exist, at least. "The number determined genetically is usually much higher than the number observed," said Rolf Holderegger.