Taxonomic distinctness (European groundfish)

The aggregation matrix for the NW European beam-trawl survey data on groundfish assemblages (93 species in 277 samples, from 9 sea areas) was last seen in Section 11, where it was checked for consistency. However, the workspace is now rather cluttered so open a new one in C:\Examples v7 \Europe groundfish, containing data Groundfish density and Groundfish taxonomy, and save it as Groundfish ws2. Here, data and aggregation matrices have the same full set of species, in the same order. With Groundfish density as active sheet, run Analyse>DIVERSE and on the Taxdisc and Phylogenetic tabs, check (✓) all the quantitative and presence/absence options: $\Delta$ (= delta), $\Delta^\ast$, $\Delta^{\scriptscriptstyle +}$, $S \Delta^{\scriptscriptstyle +}$, $\Lambda^{\scriptscriptstyle +}$ (= lambda+), $\Phi^{\scriptscriptstyle +}$ (= phi+) and $S \Phi^{\scriptscriptstyle +}$, taking also (✓Results to worksheet). Under Taxonomy>(Type•Taxonomy) take all the defaults: (Variable info. worksheet: Groundfish taxonomy) & (Current level of sample data: Species) & (Use links>(From level: Species) & (To level: Class)) & (Weights•User specified), with the Weights left on their values of step lengths of 1 between all levels. Take also the number of species ($S$) and Simpson evenness $1-\lambda$, from the Other tab. Look at the correlation between these indices by Plots>Draftsman Plot. (To obtain the plot overleaf, the axis scales have been switched off by unchecking (✓Show scales) from Graph>Special).

ScreenshotPage271a.png

ScreenshotPage272a.png

In the draftsman plot, note particularly the first column of plots, which set each index against the number of species, $S$. These bear out the general observations of Clarke KR & Warwick RM 2001, Mar Ecol Prog Ser 216: 265-278, and Chapter 17 of the CiMC manual, that:


Revision #46
Created 4 November 2024 20:47:08 by Arden
Updated 26 February 2025 01:12:36 by Abby Miller