CONCLUSION
Our study showed that the pattern of the mean elevational range size of
birds in Lebu Valley was a hump-shaped pattern, and species mean
elevational range size negatively correlated with annual temperature
range and positively correlated with the normalized vegetation index.
While habitat heterogeneity was weakly correlated with species mean
elevational range size. These results showed that all the hypotheses
examined in our study (the climate variability hypothesis, the ambient
energy hypothesis, and the habitat heterogeneity) failed to predict the
elevational range size pattern of breeding birds in Lebu Valley. Given
the uncertainty in species range size pattern, the generality of related
hypotheses explaining the mean range size of species pattern remains to
be further tested. Moreover,
species inflow intensity could directly impact the species richness
pattern in addition to the environmental factors. Our study
provided new insights into the
relationship between species richness pattern and species range size.