Extrapolative Estimation of Benthic Diatoms (Bacillariophyta) Species Diversity in Different Marine Habitats of the Crimea (Black Sea)

Abstract

Benthic diatoms species richness was analyzed based on 93 samples collected at 8 areas of Crimea (Black Sea) on sandy/muddy bottoms within depth range 6–48 m. Totally 433 species were found. Expected species richness S exp was estimated by application of Jack-knife -1 and -2, Chao-2, and Karakassis- S ∞ estimators. Magnitude of S exp , resulted from S ∞ , displayed the most similar values to the observed species number ( S obs ). Overestimation of S obs (10–13%) occurred for small number of samples (<12), and slight underestimation (3–5%) occurred when sample numbers exceeded 40–43. The other estimators gave large overestimated results (Chao—from 21 to 70% higher than S obs , Jack-knife—23–58%). The relationship between number of samples ( X ) and number of observed species ( Y ) was calculated considering all 93 samples: Y = 79.01 ln x + 34.95 . Accordingly, not less than 10 samples are required for disclosing about 50% of the total species richness (433); to detect 80% (347 species) not less than 46 samples should be considered. Different configurations of S ∞ method were applied to optimize its performance. The most precise results can be achieved when the calculation of the S exp is based on sequences of randomized samples with sampling lags of 10 to 15.