4.5 Determinants of plant elevational patterns
In summary, this study showed that the changes in the elevational
distribution of plants groups in the Yatsugatake Mountains were
different from those predicted with the pertinent hypotheses but were
rather directly and indirectly influenced by climate and its effect on
plant-plant interactions. Therefore, our results correspond to
Hypothesis 4, indicating that the applicability of hypotheses for
predicting plant elevational patterns largely depends on the environment
in the targeted study site.
Our findings demonstrated that the plant groups responded differently to
different elevational gradients. These differences may amplify the
effects of climate change in montane ecosystems. In particular, given
that the plant diversity on the subalpine-alpine transition zone was
based on the balance of plant-plant interactions, this ecotone may be
vulnerable to climate change.
Previous studies reported that plant–plant interactions change the
alpha diversity of plant groups among elevations (Bruun et al., 2006;
Stehn, Webster, Glime, & Jenkins, 2010; Sun et al., 2013); this study
went one step further and revealed that these interactions affect the
beta diversity and dominance of plant functional types. These results
imply the importance of studies on elevational patterns using
multi-plant groups and multiple indices of plant diversity (e.g, alpha
and beta diversity and functional types) to comprehend the interactions
among plant groups. Specifically, given that plant functional types
consist of those species with similar characteristics and are applied to
other areas with different flora, our results linked to functional types
can be useful to understand the mechanisms that shape plant diversity
along elevations.
TABLE 1. Relationships between the alpha diversity of different
plant groups and climatic factors in the Yatsugatake Mountains in
central Japan, obtained using generalised linear models.