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Measuring biodiversity requires a carefully thought-out and highly standardised method.

To measure the landscape diversity of plants and butterflies, the field surveyors pace off a distance in the Z7 area defined on the map (a transect) 2.5 kilometres long and record all the species that they find as they go. To survey birds, surveyors cover an area measuring one square kilometre.

However, a single visit to the sampling area is not enough. The sampling areas are generally surveyed two to three times a year in order to ensure that seasonal differences in species composition are considered. The butterfly surveys even require up to seven surveys per season.

  
 

 

 Monitoring Species Diversity in Landscapes (Z7 indicator)

Video Indicator Z7


For a survey in a habitat, field biologists search for sampling areas of ten square meters using GPS and magnetic search devices. Once the magnet has been located, the biologists measure habitat diversity by inventorying the vascular plants, molluscs and mosses within a radius of 1.8 meters (about 6 feet).

The species are recorded in the field using a handheld computer. This eliminates the need to transfer data from a field notebook to a computer. However, it is often necessary to collect samples of certain species so that they can be conclusively identified at home or in the laboratory. Mosses and molluscs are forwarded to specialists for identification. The defined BDM methods require the surveyors to work very exactly.

Monitoring Species Diversity in Habitats (Z9 indicator)

Video Indicator Z9
  
   



Surveying methods are clearly and vividly explained in a leaflet (in German).

Locating the sampling area
The exact position of the sampling area is determined by using a magnetic search device. The exact same area is surveyed again every five years.
     
Identifying plants
Vascular plants are identified on site, if possible.
     
Recording a finding
The species that are found are recorded on a report sheet. Sometimes the data are entered directly into a handheld computer in the field.
     
Taking soil samples
Molluscs and mosses cannot be identified in the field; they must be identified by experts in the laboratory. The field surveyors therefore collect samples and send them to the coordination office.  
     
 
       
    > How precise are the data?  
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