The relationship between species richness and taxonomic distinctness in freshwater organisms

Abstract

Taxonomic distinctness is a newer biodiversity measure that emphasizes the average taxonomic relatedness between species in a community. We examined whether species richness (SR) and taxonomic distinctness (TD) were significantly related and whether they showed similar environmental relationships in regional data sets for various groups of freshwater organisms, ranging from lake mollusks and fishes to stream diatoms and invertebrates. We found that the relationship between SR and TD varied widely, ranging from significantly negative through nonsignificant to significantly positive. In general, SR and TD were related to different environmental gradients, although the particular environmental variables accounting for biodiversity patterns varied among data sets and, more importantly, even between different data sets for the same organism groups. SR and TD can provide complementary views of the variability of biodiversity. These findings thus underline the importance of considering a set of different measures in the assessment of community-level biodiversity, as well as considering this variability when determining anthropogenic effects in freshwater ecosystems.

Concordance between different measures of biodiversity in Indian Ocean macroalgae

“…This accords with recent observations obtained mainly from aquatic fauna datasets (e.g. Ellingsen et al 2005, Heino et al 2005. In particular, one taxonomic category may not be a reliable surrogate for biodiversity in another, nor the group as a whole.…”

“…Hence, one phylum is not necessarily a reliable surrogate for another or for overall biodiversity, nor are patterns necessarily the same for different metrics. Similar findings emerged from a recent study of freshwater invertebrates, microflora (diatoms), bryophytes and fish (Heino et al 2005). Apart from this and an earlier study of diatoms (Izsak et al 2002), we are unaware of studies that have comprehensively examined relationships between S and Δ + in aquatic flora.…”

Can excluding non-insect taxa from stream macroinvertebrate surveys enhance the sensitivity of taxonomic distinctness indices to human disturbance?

“…Heino et al, 2007;Milošević et al, 2012). In addition, Heino et al (2005) showed that number of species was variably related to + in Finland for a number of stream and lake organisms, with correlations ranging from significantly negative through nonsignificant to significantly positive. These results indicated TD indices could provide complementary information about the variability of biodiversity in addition to traditional diversity indices.…”

Are Taxonomic Distinctness measures compliant to other ecological indicators in assessing ecological status?

“…Studies like Heino et al (2005) showed that Taxonomic Distinctness also varies along natural gradients and it is unlikely that a site can be determined to be degraded or not degraded based only on the measure of Taxonomic Distinctness. On the other hand, although Average Taxonomic Distinctness has the ability to discriminate properly between polluted and non-polluted areas in those of low number of species (as it is the case of the subtidal communities in Mondego), the results of this study demonstrated that its power of discrimination decreases when the number or species increases (see confidence limits in the funnel graphic representation, Fig.…”