3.3. | Phylogeny-Weighted β-Diversity
Phylogeny weighted β-diversity (weighted UniFrac distance) was
significantly correlated with Julian date (R2 =
0.02, p = 0.01), longitude (R2 = 0.03 ,p = 0.01), sandwort presence (R2 = 0.03,p < 0.01), and beach pea availability
(R2 = 0.02, p = 0.02; Table S4,
Supporting information). A positive correlation was again observed
between the longitudinal distance separating horses and
weighted UniFrac distance (Mantel
test: rpearson = 0.33, p <
0.01). Similarly, in a univariate PERMANOVA, band membership was found
to be significantly correlated with weighted UniFrac distance
(R2 = 0.69, p < 0.01).
Log-transformed weighted UniFrac β-dispersion was greater among horses
with access to sandwort (p < 0.01) but negatively
correlated with beach pea abundance (p = 0.01, Table S5,
Supporting information). Of note, β-dispersion in weighted UniFrac space
trended towards being higher among mares with foals than those without,
although this effect was marginally non-significant (p = 0.06).