TDV-optimization: A novel numerical method for phytosociological tabulation

• DOI: 10.3897/vcs.140466
• Publication Date: 2025-04-17T12:27:06Z
• Authors: Tiago Monteiro-He...

I present the Total Differential Value (TDV), an index designed for vegetation analysis based on operational concept of differential species, as classically illustrated by Heinz Ellenberg and Dieter Mueller-Dombois. Given a phytosociological table grouping its relevés, TDV is obtained averaging (DiffVal) each species in table. DiffVal, grounded combinatorial-discrete mathematics, quantifies power species. The novelty this approach lies distinction between two types absences: (i) absences from some relevés within group (ii) all representing group. By leveraging distribution among groups, method effectively distinguishes non-differential illustrate computation DiffVal show that, because only contribute to TDV, it reflects strength patterns classified can be optimized (TDV-optimization), providing partitions relevés. demonstrate TDV-optimization using both artificial well-known real-world data set. Key features include ability identify very closely resembling manual tabulation detect reticulate patterns. may lead where outlier or extreme are isolated groups; however, enforcing minimum size highlight with more balanced sizes. An R package now available, implementing calculation well TDV-optimization. Abbreviations : = Value; EllPar Ellenberg’s partition into three NDR number discrepant relevés; NSS significant species; Value.