Abstract

OYAGUE-PASSUNI, Eduardo. Discussion about the number of sample units and the unit sample size for estimation of the benthic macroinvertebrates density value in lotic environments. Ecol. apl. [online]. 2009, vol.8, n.1-2, pp.61-70. ISSN 1726-2216.

This paper discusses the appropriate number of Sample Units and the Minimum Sample Size (MSS) to determine the least biased value for estimating the density of benthic macroinvertebrates. This analysis applies to sections with similar physiographic and ecosystem characteristics in lotic habitats of mountainous rainforest. The data analyzed were obtained from intensive sampling using the Surber net method in an Andean-Amazonic piedmont river in central Peru (Colorado River, Chanchamayo river basin, Chanchamayo province in Junin). The results indicate that collecting efforts less than 12 Sample Units and individual samples equal or less than five replicates provide low quality data for density estimation. The results here obtained were compared with some empirical density estimations cited in Peruvian journals and technical reports since year 2000.

Keywords : Benthic macroinvertebrates; density; Minimum Sample Size; Sampling Effort; extrapolation; secondary production.

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