Open AccessProblems in using Beals' index to detect species trends in incomplete floristic monitoring data (Reply to Bruelheide et al. (2020))
Author(s) -
Christensen Erik,
Christensen Björn,
Christensen Sören
Publication year - 2021
Publication title -
diversity and distributions
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.918
H-Index - 118
eISSN - 1472-4642
pISSN - 1366-9516
DOI - 10.1111/ddi.13276
Subject(s) - floristics , index (typography) , ecology , data set , diversity index , geography , habitat , set (abstract data type) , statistics , physical geography , mathematics , computer science , species richness , biology , world wide web , programming language
Bruelheide et al. ( Diversity and Distributions , 26, 2020, 782) explored repeated habitat mapping data to identify floristic changes over time on the basis of two surveys. Because of the incompleteness of the data, they utilized the Beals' index based on the aggregated data from both surveys as a statistical tool for the analysis. The aim of this note is to illustrate problems of this approach, which in particular is shown to produce a systematic underestimation of species decrease (and—potentially less relevant in practice—increase). A specific set of model cases will be introduced to show the effects of unjustified usage of the Beals' index in this specific form.