Adaptation of constant effort sampling and of removal trapping for the estimation of populations of microscopic organisms in dense substrates ()

Abstract

AbstraetLárge numbers of thecamoebae are found in the sand and detritus substrate of small streams in the Amazonian terra firme forest. Their rei ative populatlon densities can be determined by searchlng and countlng thecae under a dissecting microscope for a standard time lnterval (constant effort sampling) . The total population per sample can be calculated from a gradual linear depletion during successive such counts In a given sample (remova! trapping). From a series of such regressions the total number o…