Influence of methodological choices on results of macrofaunal functional feeding diversity and evenness analyses
Qingtian Zhang, Zijuan Gong, Jing Li, Guikun Hu
Abstract
Methodological choices made when studying functional feeding groups (FFGs) may influence the outcome of feeding diversity analyses and of the ecological quality assessment. We assessed the impact of select methodological choices based on seasonal macrobenthos surveys carried out in Bohai Bay, China. Results of the paired-sample t test showed that the choice to remove rare species from analyses had influence on the outcome of ecosystem evaluations based on FFG diversity (t = 2.328, p = 0.023). On the other hand, although results at some stations indicated that the removal of rare species did not affect feeding diversity and ecological assessment, it increased the research effort. Evenness feeding diversity calculated from FFG biomass data showed a remarkably different spatio-temporal distribution from that of values based on abundance data, with no clear relationship between the two. If biomass data are used to estimate FFG diversity, a revised ecological assessment scale may need to be developed.