Transcript Chapter 23

CHAPTER 23
Multivariate Experiments
Tables, Figures, and Equations
From: McCune, B. & J. B. Grace. 2002. Analysis of
Ecological Communities. MjM Software Design,
Gleneden Beach, Oregon http://www.pcord.com
Figure 23.1. Four approaches to analysis of multivariate
experiments in community ecology.
Mantel test
MRPP
Attributes
Attributes
Group 1
Sample
units
Group 1
Group 2
Group 2
Figure 23.2. Comparison of data grouping for Mantel
tests and MRPP.
Figure 23.3. Vectors representing trajectories of sample units in
species space. Solid vectors represent treated sample units;
dashed vectors represent controls.
Figure 23.4. Treatment and control vectors translated to put
the tails on the centroid. Vectors represent trajectories of
sample units in species space.
Figure 23.5. Compositional vectors first translated to put the
tails on the centroid, then standardized to unit length.