Beta diversity and taxonomic sufficiency: Do higher‐level taxa reflect heterogeneity in species composition?

Abstract

Aim Virtually all studies exploring the use of taxonomic surrogates in assessing patterns of diversity have focused on clear shifts in the location of samples in multivariate space. The potential use of coarser levels of taxonomic resolution to detect patterns of variability in multivariate space, corresponding to β‐diversity in the case of presence/absence data, remains unexplored. Here we considered five ecological data sets of highly diverse marine molluscan assemblages to test the hypothesis that patterns in compositional heterogeneity would be maintained at coarser levels of taxonomic resolution. Location Italy, Norway, New Zealand and the Arctic. Methods We used multivariate dispersion based on the Jaccard resemblance measure of presence/absence data as a measure of β‐diversity to test the null hypothesis that patterns of heterogeneity in species composition for molluscs would be maintained at coarser levels of taxonomic resolution. Tests to compare β‐diversities among groups (based on distances to centroids and using 9999 permutations) were carried out separately for each of five data sets at the species level and then for each of genus, family, order and class levels. Results Differences in multivariate dispersion at the species level (heterogeneity in the identities of species) were maintained for genera and for families, but not at coarser levels of taxonomic resolution (order or class). These results were consistent across all data sets, despite differences in their spatial scale and extent, geographical location, environmental and habitat features (benthic soft sediments, rocky reefs or kelp holdfasts). Main conclusions These results suggest that either genera or families may be used as effective taxonomic surrogates to detect spatial differences in β‐diversity for molluscs. The use of surrogates can provide considerable sampling efficiencies for biodiversity assessments. We consider, however, that a degree of caution and more work is needed, as heterogeneity at the species level may not be reflected by taxonomic surrogates at smaller spatial scales.

A framework for quantifying the magnitude and variability of community responses to global change drivers

“…4B) We hypothesized that no change in mean with an increase in variance should be observed with species reordering, loss, or gain, but only when these changes occur for rare species, or with changes in species evenness (Table 1). Terlizzi et al (2009) examined changes in the composition of marine benthic mollusk communities that were either located adjacent to or far from gas drilling platforms in the Ionian Sea off of the coast of Italy. They observed no change in mean (as measured by PERMANOVA), but an increase in variance (as measured by PERMDISP, a permutational test for homogeneity of variance) of mollusk communities located adjacent to the gas platforms.…”

Taxonomic structure and the effectiveness of surrogates in environmental monitoring: a lesson from polychaetes

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Taxonomic resolution in parasite community studies: are things getting worse?

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