Webb et al. 2002, Cavender-Bares et al. 2004

Webb et al. 2002
I still am trying to understand the second column of Table 1. It is hard for me to figure out why a single pattern (or lack of pattern) should be associated with the convergence of traits in each case. Does the convergent evolution of habitat preference result in overdispersion because it is phylogenetically clustered, but in several disparate clades? Why does trait lability result in overdispersion rather than a lack of signal in this case, and why is this situation expected to differ under convergence and competitive exclusion?

Cavender-Bares et al. 2004
Figure 4 reminds me of plots which attempt to evaluate the prevalence of allopatric versus sympatric speciation by plotting the extent of range overlap as a function of the phylogenetic/genetic distance between species pairs (as was brought up in Webb 2002). I suppose they differ slightly in that the species in question may have ranges that overlap completely on a coarse scale while they never cooccur within a given community due to smaller scale habitat partitioning. But I find it interesting that a similar sort of plot is used to answer two seemingly disparate questions. Is it a problem that a similar pattern can be produced by these two distinct processes, and how can they be distinguished? Are there links between the two processes?