Can we compare lichen diversity data? A test on skilled working groups

Epiphytic lichens have long been used as ecological indicators. Lichen biomonitoring surveys were carried out by five experienced teams and the results compared across the entire process, from sampling design planning to species counting. The five teams received the same background information and worked in parallel but independently in the same area. European standard operating procedures (SOPs), which are still in preparation, were followed in order to identify possible critical issues and improve consistency. Five exercises with progressive reduction in the degree of operational freedom were carried out by the teams. The results revealed differences between teams on each exercise and showed that investigations run by different teams in the same area and at the same time may not be entirely comparable. This was partly due to inherent differences between crews (skills, familiarity with local flora, and accuracy in applying SOPs), partly to ambiguities in the SOPs, and partly to insufficient training with the SOPs. The results may be valuable in improving biomonitoring procedures and in achieving high-quality, consistent lichen diversity data.