Can Testate Amoebae (Protozoa) and Other Micro-Organisms Help to Overcome Biogeographic Bias in Large Scale Global Change Research?

Abstract

To monitor global change, large scale long term studies are needed. Such studies often focus on vegetation, but most plant species have limited distribution areas. Micro-organisms by contrast are mostly cosmopolitan in their distributions. To study the relationships between organisation groups, we analysed the testate amoebae (Protozoa), vegetation, and water chemistry of five Sphagnum peatlands across Europe. Inter-site differences were more pronounced for the vegetation than for testate amoebae species assemblage. Testate amoebae represent a useful tool in multi-site studies and environmental monitoring of peatlands because: 1) the number of species is much higher than for plants, 2) most species are cosmopolitan and are therefore less affected by biogeographical distribution patterns than plants; thus differences in testate amoebae assemblages can be interpreted primarily in terms of ecology, 3) testate amoebae can be used to analyse and monitor small scale (cm) gradients that play a major role in the functioning of peatland ecosystems. We further studied the effect of elevated CO₂ on microbial communities in the same peatlands. Elevated CO₂ increased the biomass of heterotrophic bacteria and decreased the biomass of medium size protozoa (mostly small testate amoebae). These effects suggest changes in community functioning that may have feedback effects on other components of the ecosystem.

Testate amoebae analyses for all sites, vegetation analyses for the Swiss site and data analyses.

Analyses of micro-organisms.

Water chemistry analyses and vegetation analyses for the Dutch site.

Vegetation analyses for the British site.

Vegetation analyses for the Swedish site.

Vegetation analyses for the Finnish site.