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. 2020 Jul 5;10(14):7261–7275. doi: 10.1002/ece3.6452

Table 3.

List of measures with n being the number of observations, d the total number of dimensions, k any specific row in the matrix, Centroid being their mean and σ 2 their variance. Γ is the Gamma distribution and λi the eigenvalue of each dimension and qi and pi are any pairs of coordinates

Name Definition Captures Source Notes
Average Euclidean distance from centroid
in(kn-Centroidk)2d
Size Laliberté and Legendre (2010) The functional dispersion (FDis – without abundance)
Sum of variances
idσ2ki
Size Foote (1992) Common measure used in palaeobiology (Ciampaglio et al., 2001; Wills, 2001)
Sum of ranges
id||maxdi-mindi||
Size Foote (1992) More sensitive to outliers than the sum of variances
Ellipsoid volume
πd/2Γd2+1idλi0.5
Size Donohue et al. (2013) Less sensitive to outliers than the convex hull hypervolume (Blonder, 2018; Díaz et al., 2016)
Minimum spanning tree average distance
branchlengthn-1
Density Sedgewick (1990) Similar to the unscaled functional evenness (Villéger et al., 2008)
Minimum spanning tree distances evenness
minbranchlengthbranchlength-1n-11-1n-1
Density Villéger et al. (2008) The functional evenness without weighted abundance (FEve; Villéger et al., 2008)
Average nearest neighbor distance
inmin(qi-pi)2)×1n
Density Foote (1992) The density of pairs of observations
Average displacement
in(kn)2in(kn-Centroidk)2
Position This paper The ratio between the observations' position from their centroid and the center of the trait space (coordinates: 0, 0, 0,…). A value of 1 indicates that the observations' centroid is the center of the trait space