Evaluation of species richness estimators in studies of diversity involving two larval digenean communities parasitizing snail hosts

M. J. MERLO; M. PARIETTI; J. A. ETCHEGOIN

PARASITOLOGY RESEARCH

SPRINGER

Año: 2010 vol. 107 p. 1093 - 1102

0932-0113

he nonparametric estimators of species richnessare some of the most widely used extrapolation methods instudies of biodiversity. These studies need relative largesamples to achieve total diversity (including rare species),and estimators are routinely used to alleviate this problem.In the existing literature, parasite communities havereceived little attention. In fact, the present study is thefirst dealing with parasites in invertebrate hosts. Real dataon seasonal diversity of larval digeneans in the snailsHeleobia conexa and Heleobia australis from Mar Chiquitacoastal lagoon (Argentina) were used to evaluate sevennonparametric estimators of species richness, observing thebehavior of each method and its ability to estimate therichness using different subsample sizes. In addition,estimated species richness was compared with the previ-ously observed species richness in the parasite componentcommunities of both snail hosts, and the minimum samplesize, necessary to include all the observed species of larvaldigeneans, was estimated using the nonparametric estima-tors. The bootstrap method had the best overall perfor-mance in the two communities. Although this estimatorrequired large subsamples to estimate sample richness, itwas in general the least biased and most accurate, and itpresented the most similar curve shapes with lack of erraticbehavior through the seasons. The results obtained from thecomparison between the minimum sample sizes estimatedin previous studies of both snail hosts and those suggestedby the estimators also support the use of species richnessestimators as methods to calculate the minimum samplesize in studies of diversity.