Phylogenetic signal and traits
In addition to the functional and phylogenetic clustering with
increasing elevation, there was a significant phylogenetic signal in
some of the functional traits of river birds as indicated by K and K*
values (p < 0.05)
for body mass (K=1.2332), bill size (K=1.4098) and tarsus length (K=
1.0725) (Table 1). In other words, similarities in these traits between
species reflected strong phylogenetic
effects. Among these three traits
with a strong phylogenetic signal, community-weighted mean values for
body mass and bill length declined with elevation, but there was no such
effect in tarsus length (Fig. 3). In contrast, K values for body size,
tail length and breeding traits indicated more substantial variation
among related taxa, though only for body size was this effect formally
significant (Table 1). Judged on Moran’s I values, tarsus length and
body mass had positive values while bill length had a negative
autocorrelation with phylogenetic distance (Fig.
S5).