Plant growth forms shaping biodiversity patterns can guide conservation planning on the Qinghai-Tibet Plateau

Abstract

Plant growth forms effectively reflect profound evolutionary adaptations that underpin ecosystem functioning; however, how their biogeographic disparities influence conservation prioritization remains poorly understood. We here integrate a comprehensive phylogeny with high-resolution distribution data for 14,468 vascular plant species across the Qinghai-Tibet Plateau, showing that growth-form identity decouples the spatial patterns of taxonomic and phylogenetic diversity, with distinct forms exhibiting marked differences in geographic range sizes and elevational optima (2,200-3,300 m). Although herbs dominate plant assemblages across spatial scales, their proportional abundance decreases along a northwest-to-southeast aridity gradient, yielding to structurally complex, non-herbaceous forms in humid, species-rich regions. Consequently, priority conservation areas derived for individual growth forms exhibit low spatial similarity. Despite this divergence, we identify trees and climbers as highly effective umbrella growth forms: prioritizing these functional groups captures [≥]75% of the multidimensional diversity of all other growth forms within a minimal spatial footprint. Our findings demonstrate that accounting for growth-form-based functional identity is essential for maximizing conservation efficacy, providing a scalable framework for biodiversity hotspots worldwide.