Surrogates for species

Posted on March 23, 2016

Ecological communities are commonly defined and compared by reference to their species composition. However, in the case of many types of organisms, such as freshwater plankton, species-level identification is a slow, error-prone process, and for this reason there’s growing interest in characterising communities by carrying out identification at a higher taxonomic level (genus or family). To explore this idea, biologists classified the phytoplankton and zooplankton communities in 29 lakes in the Araguaia River floodplain in central Brazil, and examined the agreement between alternative biodiversity indices (numbers of species, genera and families). In total, 115 phytoplankton species and 159 zooplankton species were identified. For both types of plankton, there were significant correlations between richness at the three taxonomic levels. In the case of phytoplankton, classifications of lake communities were also concordant with classifications based on environmental variables, while zooplankton communities were significantly related to environmental variables only at the species level. The richness correlations indicated that identification could be carried out at a higher taxonomic level without significant loss of information.
Results from other studies suggest that associated time savings and the ability to involve less experienced personnel in identification could reduce field costs by 60-80%.

Reference: Machado, K. B. et al. 2015. Using lower taxonomic resolution and ecological approaches as a surrogate for plankton species. Hydrobiologia 743, 255–267.