With respect to methodology, another aspect that would
deserve more attention is the seasonal and spatial variability in soil
protist density, diversity and community structure. In this study, we
did only one sampling campaign in early spring but Warner et al.
[58] and Lousier [59] reported important seasonal variation in
testate amoeba communities in an open bog/fen and Lund [4]
indicated that soil diatom abundance can decrease considerably
during summer droughts. Clearly, more data are required to better
understand the relationship between protist communities and
seasonal changes and to assess if the differences observed among
treatments are comparable through the year. Such information is
crucial to develop biotic indices based on diatoms and testate