Ecology of testate amoebae in a North Carolina pocosin and their potential use as environmental and paleoenvironmental indicators

Abstract

Testate amoebae inhabiting Sphagnum peatlands are sensitive indicators of substrate-moisture content. However, ecological data from a range of peatland types is needed to assess their indicator-value in other peatland systems. We examined testate amoeba communities and species—environment relationships at 40 locations within a pocosin of North Carolina. Primary objectives were to provide baseline data on the ecology of testate amoebae in pocosins, compare communities with those of northern peatlands, and assess the potential of using testate amoebae as environmental indicators in these systems. Results indicated that pH, substrate-moisture content, and conductivity were important controls on community composition. Communities that were relatively similar and dissimilar to those of northern peatlands were encountered, and the ecology of species with respect to water-table depth was similar in both peatland types. Cross validation of transfer functions for pH and water-table depth suggests that pocosin testate amoebae can be used as indicators for these variables. However, water-table depth was poorly inferred from communities at several dry sites characterized by high bulk density. These sites may experience large seasonal or interannual variability in moisture conditions because of differences in peat structure, suggesting that research is needed on the influence of short-term variability in shaping community structure.