ミズゴケ湿原に生息するササラダニ類の生態

抄録

The ecology of oribatid mites in Sphagnum mires, especially with regards to the structural features of the fauna, life-history traits of some populations and their role in the habitats, was reviewed. The most characteristic feature of the fauna was found to be the small number of species and very high density. The scarcity of species observed was affected by two main factors: the high level of soil moisture and the limited variety of vegetation. High density was observed under conditions of excess food materials and sufficient microhabitats combined with a low predation pressure. The fauna showed an increase in species diversity with a decrease in soil moisture and an increase in plant composition. The characteristic genera found in hollows on high moor were Limnozetes, Trimalaconothrus, Malaconothrus and Trhypochthoniellus. In hummocks, these genera were decreased in number, and common genera such as Oppiella, Tectocepheus and Suctobelbella dominated. Many thelytokous species, some of them deposited larvae, have a long generation time and a rather stable adult population. It is suggested that the stable population results from extended development, adult longevity and iteroparity driven by a low metabolic rate. They are also panphytophages and important decomposers of a wide range of biological materials although the individual contribution to the habitat is relatively small.