Results
In small sytem, six scenarios started from one guild and the eleventh habitat association were collapsed, because the environmental tolerance of guild was nearly zero (< 0.0052). The results presented here were based on 819 simulation outcomes.
Across scenarios, the number of guilds in system achieved first to a stationary state; then, the species richness converged eventually to a dynamical equilibrium through speciation-extinction balance. The number of guilds achieved to a stationary state faster in higher dispersal rates (Fig. 3).
In the model communities resulted with only one guild, the functional uniqueness was zero; however, the relative portion explained by environmental component in total explained variation was positively biased in linear environmental gradient (Fig. 4a). The type I error of pure environmental component was inflated in these scenarios. The spatial and pure spatial components were always significant (Fig. 4b).
In the model communities resulted with more than two guilds, the functional uniqueness and redundancy presented the opposite pattern across ecological-evolutionary scales. The functional uniqueness increased in an area packed within a biogeographic unit, that was referred well by the relative portion explained by environmental component in the total explained variation of overall model (Fig. 5a). The power of pure environmental component increased in these scenarios. The spatial and pure spatial components were always significant (Fig. 5b).
If the pure environmental component of overall model was significant, the hierarchical guild structure and the spatial structures found within and among patchy habitats were usually significant (Fig. 5b). Furthermore, the total explained variation and the relative portions explained by environmental and pure spatial components in total explaind variation were similar between overall and hierarchical models; however, the number of guilds coexisted in model communities was often larger than the number of habitat types identified by the k -means partitioning of linear combination scores (scaling 1) and simple structure index criterion (Fig. 5a).
In the model communities resulted with only one guild, the Mantel correlations of true spatial component approached to zero in an area packed within a biogeographic unit (Fig. 6a). They were always significant in an area encompassing independent biogeographic units, and vanished only in some scenarios for an area packed within a biogeographic unit (Fig. 6b). The Mantel correlations of false environmental component also approached to zero in an area packed within a biogeographic unit (Fig. 6a); however, they were often significant, and did not control correctly the false detection in linear environmental gradient (Fig. 6b).
In the model communities resulted with more than two guilds, the Mantel correlations of true environmental component negatively departed in an area packed within a biogeographic unit (Fig. 7a), and tended to emerge the pattern of spatial autocorrelations (Fig. 7b). The Mantel correlations of the spatial structures found by hierarchical model in each environmental context were often significant (Fig. 7b).