Biodiversity assessment using DNA extraction from soil samples from permanent soil monitoring sites (MetaSOL)
Germany lacks a nationwide and standardised survey of soil organisms, although a comprehensive infrastructure for this is available with the approx. 800 Permanent Soil Monitoring Sites (BDF). However, not all federal states conduct their own soil biology surveys on their BDF. The most important reason for this is probably the time-consuming and expensive identification of soil invertebrates. The present project should contribute to solving this problem. Earthworms, enchytraeids and collembolans were sampled at 25 sites, the animals were determined morphologically and by DNA metabarcoding, and the results were compared with each other. The aim was to develop recommendations for an efficient and routinely implementable monitoring of soil fauna within the German BDF programme. The results showed that genetic identification methods are basically suitable for this purpose. Before they can be introduced into official practice, several preconditions still must be met. DNA reference databases must be comprehensive, well curated and quality controlled. DNA-based methods need to be standardised. Robust indices of soil health based on soil organism data need to be developed. It is recommended that soil fauna surveys be carried out to the same extent and using the same methods in all federal states. Soil organisms should first be regularly recorded using classical morphological methods, at least earthworms, enchytraeids and collembolans. The inclusion of further groups should be examined. Genetic methods should be introduced gradually, starting with earthworms. The data collected should be compiled centrally and made available to the public. In the long term, environmental DNA metabarcoding should be used as standard for investigating and assessing soil biodiversity. This project was funded by the German Environment Agency (FKZ 3717 74 234 0).