3.2. Relationship between environmental energy, climatic
seasonality, water availability and richness pattern
Generalized linear models showed that the explanatory variables of
environmental energy, particularly MAT and PET, were stronger predictors
than that of climatic seasonality and water availability, and they
showed a negative relationship to all richness groups (Table 1). MAT
explained 6-19%, whereas PET explained 4-19% of the total variance in
species richness. The proportion of variance also showed the significant
role of environmental energy in determining species richness,
particularly endemic-threatened (Fig. 2). In comparison with topographic
and soil predictors, environmental energy, climatic seasonality, and
water availability showed much lower contribution in the variation of
species richness of all categories except endemic-threatened species
richness, the environmental energy showed much higher contribution than
soil type predictors (Fig. 2). Hierarchical partitioning modelling
showed similar results to GLM models and suggested that environmental
energy and climatic seasonality showed a high joined effect for all
groups, while water availability had a highly independent effect (Fig.
3).