Protistology 5 (4) 268-280 (2008)
Biodiversity patterns in protozoan communities: linking processes and scales*
Yuri Mazei
Department of Zoology and Ecology, V.G. Belinsky State Pedagogical University, Penza, Russia
Summary
One of the general questions in ecology is how patterns of species diversity change across spatial scales. In this study additive partitioning methodology,
which allows estimating relative contributions of alpha and beta diversity components to total diversity, was applied to data on protozoan (heterotrophic flagellates
and testate amoebae) communities from sphagnum bogs collected from a nested design consisting of five hierarchical levels. It allowed evaluating additive diversity
partitioning on four spatial scales: 1) the Russian plain vs. ecoregions, 2) ecoregions vs. ecosystems, 3) ecosystems vs. sites, and 4) sites vs. samples.
A significant percentage of total species richness was attributed to beta diversity between ecoregions and among ecosystems (different bogs) within ecoregions.
Protozoan communities seem to be alpha-dominant at the broadest spatial scale and beta-dominant at finer scales. A switch in relative dominance from beta to alpha
diversity with increasing spatial scale suggests scale transitions in ecological processes. Tis pattern is likely to be a result of different processes operating at
different scales. At fine scales protozoan species interact directly, and niche partitioning is the strongest determinant of diversity, which results in differences
between local communities. At broader spatial scales, where processes such as dispersal and colonization-extinction dynamics structure the communities, these
interactions are probably not evident.
Key words: biodiversity patterns, additive biodiversity partitioning, alpha-diversity, beta-diversity, gamma-diversity, scale, microbial ecology,
protozoa, heterotrophic flagellates, testate amoebae
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