Vertical structural complexity of plant communities represents the
combined effects of resource acquisition and environmental stress on the
Tibetan Plateau
Abstract
Knowledge of vertical structural complexity (VSC) is important, because
the resulting spatial partitioning is closely linked to resource
utilization and environmental adaptation. How VSC responds to
environmental changes on large scales and its mechanisms are poorly
understood. We investigated 2,013 plant communities on the Tibetan
Plateau (TP). VSC was quantified as the maximum height (Height-max),
height variation (Height-var), and height evenness (Height-even).
Precipitation dominated the VSC variation in forests and shrublands,
supporting the classic physiological tolerance and hydraulic limitation
hypotheses. In contrast, for alpine grasslands in extreme environments,
non-resource limiting factors dominate VSC variation. Generally, with
the shifting of climate from optimal to extreme, the effect of resource
availability gradually decreases, but the effect of non-resource
limiting factors increases. Using machine learning models, maps of VSC
at 1-km resolution were firstly produced for the TP. These findings
provide new insights into macroecological studies, especially for
adaptation mechanisms and model optimization.