Point quadrat versus video transect estimates of the cover of benthic red algae

Abstract

Point quadrat (PQ) and video transect (VT) techniques were compared to determine the feasibility of using the latter to sample subtidal red algal assemblages.More taxa were found by PQs than by VTs, both overall and on a per quadrat basis.VTs tended to overestimate the percent cover of rock and articulated coralline algae.VTs were incapable of resolving many of the less common red algae.Video sampling required less time in the field than point quadrats but laboratory analysis was very time consunling.Lack of resolution and extensive laboratory analysis make this technique insufficient for sampling benthic red algal populations.However, VTs may be useful in documenting large-scale differences between regions, such as the percent cover of understory kelps or the density of large mobile invertebrates in central California kelp forests.Video sampling has been successfully used in the intertidal but traditional, random point quadrats s t d appear to be the most efficient and accurate way to sample benthlc communities in kelp forests.