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Arranging phytosociological tables by species‐relevé groups
Author(s) -
Bruelheide Helge,
Flintrop Thomas
Publication year - 1994
Publication title -
journal of vegetation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 115
eISSN - 1654-1103
pISSN - 1100-9233
DOI - 10.2307/3235854
Subject(s) - block (permutation group theory) , table (database) , sorting , mathematics , statistics , geography , ecology , computer science , biology , combinatorics , algorithm , database
Abstract. A newmethod of arranging phytosociological tables by species‐relevé groups (blocks) on the basis of the density of rows and columns (relative species frequency and relative species number) is presented. Each block fulfils a given minimum criterion regarding its density. With a density threshold of e.g. 50 %, blocks are formed with only those species that are present in at least 50 % of the block's relevés, while at the same time the block's relevés comprise at least 50 % of the block's species. The procedure starts with the complete table and iteratively masks species and relevés with the smallest densities. This is performed step by step with species and relevés and continues until the given density threshold for all species and relevés is exceeded. Without any further parameters other than the minimum density, species‐relevé groups of gradually decreasing size are formed. Data processing is performed with a computer program (ESPRESSO). The main application of the method is found in an effective pre‐sorting of relevé data. The blocks formed can be arranged in the final table as desired.