MEPS 413:81-93 (2010)  -  DOI: https://doi.org/10.3354/meps08713

Measures of taxonomic distinctness do not reliably assess anthropogenic impacts on intertidal mollusc communities

Trudy L. Costa1,2,3, Timothy D. O'Hara1,*, Michael J. Keough2

1Sciences Department, Museum Victoria, GPO Box 666, Melbourne, Victoria 3001, Australia
2Department of Zoology, University of Melbourne, Victoria 3010, Australia
3Present address: School of Biological Sciences, University of Wollongong, New South Wales 2500, Australia
*Corresponding author. Email:

ABSTRACT: Indices of taxonomic distinctness measure the taxonomic breadth of a community and may be more sensitive to human impacts than conventional diversity indices. They have the advantage of being, in theory, insensitive to sampling effort and can be calculated using presence/absence data. The average taxonomic distinctness index and variation in taxonomic distinctness index were used to assess the effects of putative human impacts on molluscan community composition at 63 rocky intertidal platforms on the coast of Victoria, Australia. The use of 2 sampling techniques, viz. timed searches and quadrats, was compared. Sites exposed to sewage discharge maintained high taxonomic distinctness, and those exposed to high levels of human visitation did not have consistently lower values than controls. Results varied, sometimes markedly, depending on which survey technique was used. Neither average taxonomic distinctness nor its variance were strongly correlated with large-scale environmental gradients, small-scale habitat differences or other diversity indices. It is most likely that taxonomic distinctness measures did not discriminate sites exposed to putative disturbance because of the high taxonomic diversity of intertidal mollusc assemblages, and because low values of taxonomic distinctness were not exclusive of impacted conditions.


KEY WORDS: Trampling · Sewage · Disturbance · TAXDTEST · Community composition · Invertebrate · Diversity


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Cite this article as: Costa TL, O'Hara TD, Keough MJ (2010) Measures of taxonomic distinctness do not reliably assess anthropogenic impacts on intertidal mollusc communities. Mar Ecol Prog Ser 413:81-93. https://doi.org/10.3354/meps08713

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