Sampling Data on the Bactivorous Ciliates of a Small Pond Compared to Neutral Models of Community Structure
1979
Taylor, William D.
Small—volume samples of bactivorous ciliates were collected from a small pond. Qualitative (presence—absence) data were obtained from a set of 230 samples collected over all seasons during 3 yr and quantitative data were obtained from 81 samples collected during one summer. Analyses of these data demonstrate that apart from a segregation of taxa between aerobic and anaerobic benthic habitats, taxa were essentially independent in their distribution among samples. There was some indication of a net association in the qualitative samples, possibly due to seasonal and annual variations in ciliate abundance. There was little tendency for faunistically similar samples to be collected from the same site, at the same time, or form visually similar microhabitats. The frequency of samples containing different numbers of individuals and the ranked species abundance lists for samples taken at the same time and site are compatible with the species undergoing a stochastic pure birth and death process with rates linearly dependent on population size. The relative commonness of species is compatible with the hypothesis that the total number of occurrences is randomly partitioned among the species. Although communities of protozoa are thought to possess a complex structure maintained by interspecific interactions, the bactivorous ciliates in the pond appear to be an assemblage of essentially independent species undergoing density—independent growth processes and generally conforming to simple, neutral models of community structure.
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