Species composition of testate amoebae [protists] and environmental parameters in a Sphagnum peatland

The research was made on the largest (ca 500 ha) peatland complex in the western Poland (“Chlebowo” mire) (N 52º44’14.3’’ E 16º45’20.7’’), that exists under considerable anthropogenic pressure. Species composition of testate amoebae in selected microhabitats was described. The fundamental environmental factors influencing the structure of assemblages were determined. Twenty four samples were taken from 10 sites (Sphagnum lawn, hollow and hummock) dominated by Sphagnum and brown mosses. Each of them was analysed in relation to its taxonomical composition. Nine environmental parameters (acidity (pH), conductivity, colour, NH₄⁺, NO₃⁻, PO₄³⁻, SO₄²⁻, Ca²⁺ and Mg²) were measured in the field and laboratory. Thirty two testate amoebae species of 13 genera were identified within the 24 sites. In most of the sites species composition was dominated by Hyalosphenia papilio Leidy, Cyclopyxis arcelloides Leidy and Hyalosphenia elegans Leidy, however the most numerous were Amphitrema flavum Archer, Hyalosphenia papilio Leidy and Cyclopyxis arcelloides Leidy. The particular parameters, i.e. pH, depth to the water table (DWT) and SO₄²⁻ content significantly explained the species variability. Multivariate analyses showed that species tend to group especially along the pH gradient; to a smaller extent along the DWT and SO₄²⁻, together with pH.