Species richness measures fail in resolving diversity patterns of speciose forest moth assemblages

Abstract

We used data from a light-trapping study at 28 sites on floodplain forest moths in eastern Austria to assess the performance of a variety of species richness and species diversity measures. At each site the data (32,181 individuals from 448 species) contain a large fraction of species represented only as singletons. Sampling effort was evenly spread across sites, but sampling success varied greatly. Influx of moths from the landscape matrix surrounding floodplain forest patches lead to substantial proportions of stray individuals from the regional species pool. Under these conditions, observed species numbers as well as eight extrapolation estimators of species totals failed to reflect differences between three study regions or between flooded and non-flooded forest habitats. Rarefied species numbers and Fisher's a of the log-series distribution captured differences in moth diversity between regions, but failed to mirror flooding impact. Only Shannon's diversity captured all expected diversity differences, at high significance levels. Application of Chao and Shen's bias correction increased figures of Shannon's diversity, but did not affect the outcome of statistical comparisons. We conclude that for species-rich incompletely sampled communities of highly mobile insects the evaluation of the complete species-abundance information using Shannon's diversity is the most promising mode to compare local species diversity with a high degree of ecological resolution. Species richness measures apart from those obtained through rarefaction cannot be recommended, as they are sensitive to sources of bias that pertain to many empirical sets of field data.

Mapping the biodiversity of tropical insects: species richness and inventory completeness of African sphingid moths

“…This indicates that rarefaction introduces less random error than extrapolation. Based on similar arguments, Fiedler & Truxa (2012) recently came to the same conclusions for finer-scale data.…”

Diversity patterns of ground beetles and understory vegetation in mature, secondary, and plantation forest regions of temperate northernChina

“…As the overall sampling efforts varied between different study regions, we used Hurlbert rarefaction to standardize and allow for direct comparison of the species richness of carabids. Hurlbert rarefaction is a proved approach allowing robust standardized comparisons of samples varying in sample sizes and underlying sampling effort (Hurlbert 2004;Olszewski 2004;Colwell et al 2012;Fiedler and Truxa 2012). We selected individual-based rarefaction for carabids rather than sample-based (trap-based) rarefaction because different numbers of samples were used per plot in the different study areas as outlined above, and we believe that the number of specimens caught by each trap increases in a nonlinear fashion with an increasing number of traps.…”

Predictability of species diversity by family diversity across global terrestrial animal taxa

“…We calculated the Shannon diversity index for each site for the species, genus and family level, respectively. Shannon diversity is the most frequently used biodiversity index and has been considered to be a reasonably good measure of diversity for taxa that are incompletely sampled (Fiedler & Truxa, ). Shannon entropy ( H ; Supporting Information Appendix S3: Equation 1) describes the degree of chaos in a species assemblage.…”