Trait conservatism
Admittedly, basic understanding on trait conservatism through
phylogenetic signal detection greatly affects our mechanistic
interpretations on assembly process (Losos 2008). Even though prior
studies have suggested that lambda is not sensitive to the size of
species pool (Wang & Clarke 2014; Blomberg et al. 2003),
however, we found both K and lambda metrics significantly varied across
datasets. Besides, most of morphological traits were phylogenetically
convergent, especially in LSD. Significant but weak signal (K<
1, p< 0.05) probably results from adaptive convergence to
particular environment and indicates labile phylogenetic signal
(Blomberg et al. 2003). These results in phylogenetic signal
detection is not surprising especially in the most diverse mammalian
lineage(Fabre et al. 2012). Environment driven convergent
adaptation in functional traits can largely promote coexistence among
distant species, efficiently reduce habitat resources caused competitive
exclusion among relatives and ultimately facilitate interspecific
differentiation in rodents (Cavender-Bares et al. 2009;
Cavender-Bares et al. 2004). Absolutely, a single comparison
between two species pools might be less comprehensive to infer general
conclusion. However, to some sense, these results have provided us an
opportunity to rethink about ‘what is phylogenetic signal per se ’
and ‘how to understand the degree of PNC by detecting phylogenetic
signal’. After all, phylogenetic signal obtained from a certain species
pool could not represent the complete evolutionary history for every
lineage (Swenson 2013).