The effects of small-scale heterogeneity on biomonitoring of desmid phytobenthos in Central European temperate mountain peatlands

Abstract Biomonitoring of the ecological status of peatlands is often based on the analysis of the dominant groups of phytobenthos, such as desmids (Desmidiales, Zygnematophyceae, Streptophyta). The most commonly used framework is based on the NCV index, which assesses the conservation value of wetlands based on the ecological traits of the desmid taxa comprising the natural assemblages. However, microphytobenthos is often characterized by remarkable small-scale variability even within ecologically homogeneous sites, and it is not clear how this heterogeneity affects the indicative values of individual samples. In this study, we compared the community structure and the NCV index scores of 32 samples collected on a microscale level in two mountain peatland pools in the Ore Mts. (Czech Republic). The observed variability was compared with regional data from a total of 96 sites. The results showed not only a significant spatial autocorrelation within individual sites, but also a relatively stable community structure and corresponding NCV values in relation to regional variation. This shows that reliable biomonitoring of peatland localities can be based on a relatively small number of samples from each pool, as the NCV index provides a robust framework compared to the small-scale variability within these localities.