Seasonal Influences on the Ecology of Testate Amoebae (Protozoa) in a Small Sphagnum peatland in Southern Ontario, Canada

Abstract

Testate amoebae (Protozoa) were studied in spring, summer, and fall from the same microhabitats in a small Sphagnum-dominated peatland in southern Ontario, Canada. A total of 32 sampling stations were established in two wetland plant communities, 19 in an open Ericaceae low-shrub community and 13 in a closed Picea mariana and Larix laricina swamp community. Sphagnum was collected in each station for analysis of testate amoebae and measurement of soil water content parameters and water table depth in May, August, and October 2001. pH and dissolved oxygen of the groundwater under the Sphagnum were measured also. A total of 52 taxa including the rotifer, Habrotrocha angusticollis, were identified. Soil water content and water table variables emerged as the primary factors separating testate amoebae between the open bog/fen community and swamp community. Testate amoebae in the open bog/fen community showed a clear separation between the May sampling period and the August and October sampling periods. Sampling stations in May had much higher water table and were wetter than those in August and October. Conversely, testate amoebae in the swamp community did not show a clear difference between sampling periods. Soil moisture and water tables appear to be more constant in the swamp communities. Biological factors or other microscale environmental factors may need to be considered to explain seasonal changes in testate amoebae. A greater understanding of relationships between testate amoebae and microenvironmental factors is necessary to track seasonality in testate amoebae distributions.

Fine-Scale Horizontal and Vertical Micro-distribution Patterns of Testate Amoebae Along a Narrow Fen/Bog Gradient

“…Our results agree with earlier studies in identifying the fen/ bog gradient as an important factor shaping the structure of testate amoeba communities [5,27,28,34,37,38,63]. Indeed in the "fen" habitat, A. flavum, H. sphagni, and H. papilio were found in greatest abundance and marked the ecological transition in Sphagnum upper segments.…”

“…Indeed in the "fen" habitat, A. flavum, H. sphagni, and H. papilio were found in greatest abundance and marked the ecological transition in Sphagnum upper segments. These species are typically found in habitats with high (>95%) soil water content [7,30,63]. Other species such as N. tincta and A. muscorum described as xerophilous [12,13] were more abundant in the "bog" habitat.…”

Using “bryophytes and their associated testate amoeba” microsystems as indicators of atmospheric pollution

“…3). These results are in accordance with the results of other studies in other environments (Mitchell et al, 1999;Warner et al, 2007;Beyens et al, 2009), where the diversity and abundance of TA are dependent on environmental conditions such as humidity, pH, soil moisture or temperature.…”

Development and refinement of proxy-climate indicators from peats

“…Studies on the ecology of testate amoebae also inform palaeoenvironmental interpretations, and although numerous studies have now provided a wealth of data on moisture tolerances and optima for most common species, there are still remaining questions. For example, the response of testate amoeba communities to seasonal-to-interannual moisture variability (Warner et al, 2007), the role of surface vegetation in modulating the microenvironment of testate amoebae, and the potential for factors besides surface moisture to influence testate amoeba community composition all need to be better understood Markel et al, 2010). Experimental studies are needed to address some of these issues and to characterise better the proximal controls (e.g., resources) on testate amoeba communities, and assess how these proximal controls are affected by water-table depth.…”