“…b-diversity can be a useful metric when trying to understand patterns of species diversity across spatial scales (e.g., Veech et al 2002, Crist and Veech 2006, Jost 2007, Tuomisto 2010a, b, Anderson et al 2011, and for example, can allow inference about the relative importance of community assembly processes such as those that are more deterministic (niche-related) relative to those that are more stochastic (e.g., Condit et al 2002, Tuomisto et al 2003, Gilbert and Lechowicz 2004, Dornelas et al 2006, Chase 2007. Unfortunately, a large number of the metrics and statistical analyses used to estimate b-diversity are confounded, are not always directly comparable, and may not produce conceptually meaningful values (Jost 2007, Jurasinski et al 2009, Tuomisto 2010a, b, Anderson et al 2011. For example, one of the biggest problems associated with analyses of b-diversity is that using either a multiplicative (c ¼ a 3 b) or additive (c ¼ a þ b) partition, b-diversity is linked to variation in c and a by definition, thus making statistical comparisons of b-diversity among sites or regions confounded by coincident variation in a or c (e.g., Wilson and Shmida 1984, Lande 1996, Koleff et al 2003, Jost 2007, Tuomisto 2010a.…”