16.10.2012

Landscape genetics: making the invisible visible

Marsh grasshopper (Stethophyma grossum). Foto: Daniela Keller

Roe deer (Capreolus capreolus). Foto: Josef Senn

Pair of tree frogs (Hyla arborea). Foto: Sonia Angelone

Landscape genetics combines landscape ecology and population genetics, enabling connections to be made between the dispersal of plants and animals on the one hand and landscape elements that act as barriers or corridors on the other. Landscape genetics therefore provides a relevant basis for the planning and implementation of nature conservation measures.

Landscape genetics is a new field of research that combines the methods of population genetics with those of landscape ecology. It allows the investigation of processes which are generally not visible and are therefore difficult to observe. For example, the connectivity of populations in a fragmented landscape can be examined:

• Where, how and how often do animals and plants disperse?
  
• Which landscape elements promote or hinder dispersal?
  

In many cases, investigating such questions is difficult using conventional methods because they only measure the dispersal of animals and plants in a indirect way. For instance, the dispersal of animals can be investigated using capture-recapture methods, in which animals are captured and marked and then recaptured after a certain time period. This allows researchers to determine how far an animal has moved and where it has travelled to. However, these methods can usually only be used across small areas. By contrast, genetic methods allow dispersal to be measured across an entire landscape, which is the level at which planning and implementation of nature conservation measures take place.

Landscape genetics is therefore becoming increasingly important in research as well as in application. It contributes to:

• expanding basic knowledge on the dispersal potential of species in a landscape, e.g. of endangered species such as the large marsh grasshopper (differentiation method)
• assessing the need for ecological restoration in nature conservation, e.g. analysis of barrier effects of roads and other transport infrastructure (genetic clustering method);
  
• monitoring effectiveness of conservation measures, e.g. connectivity of stepping stone ponds for the European tree frog (assignment tests method).