Relationship between testate amoebae (Protozoa: Rhizopoda) and microenvironmental parameters on a forested peatland in northeastern Ontario

The relative abundance of species of testate amoebae (Testacea; Rhizopoda) was established from 107 surface moss samples from a forested peatland in northeastern Ontario. These were related by multivariate analysis to a number of microenvironmental conditions including soil moisture content, water table, bulk density, humification, dominant peat component, pH, peat depth, depth of living moss, dominant surface moss species, vegetation type, microtopographical position, and artificial drainage. Moisture conditions play a key role in determining the species assemblages, pH being a secondary factor. Other environmental parameters related to species assemblages do not necessarily indicate a direct ecological link but are also associated with moisture and nutrient conditions. Individual species are ranked in terms of their preferred moisture conditions and compared with data from Finland. Certain species are restricted to either dry or wet conditions while others tolerate a wide range of moisture. Calculating weighted averages of substrate moisture contents for a greater range of species sampled from a larger number of sites will allow the development of transfer functions for constructing palaeomoisture curves from peatlands.