Leaf trait divergence and elevational adaptation in endangered Fagus hayatae: Conservation insights for an East Asian paleoendemic

Fagus hayatae Palib. ex Hayata, an endangered East Asian paleoendemic, thrives in Sichuan’s Micang Mountain while surviving fragmented in Taiwan and mainland China. However, the differentiation from congeneric species (e.g., F. engleriana) and its elevational adaptation strategies remain poorly understood. Leaf functional traits, key indicators of plant resource strategies, reveal plants’ ecological adaptation through their interrelationships and environmental responses. In this study, leaf functional trait variation between F. hayatae, F. engleriana and their associated tree species was investigated, with elevational trait syndromes in F. hayatae examined for climate adaptation insights (Micang Mountain Nature Reserve, China). Both F. hayatae and F. engleriana were community dominants with low niche overlap in overall interspecific. Compared to dominant associated tree species, F. hayatae exhibited higher leaf dry matter content (LDMC), specific leaf area (SLA), leaf carbon content (LCC), and leaf phosphorus content (LPC), along with smaller but denser stomata; in contrast, F. engleriana displayed greater stomatal density and resource-acquisition traits, including larger leaf width (LW), leaf area (LA), SLA, and LCC, as well as higher leaf nitrogen content (LNC), but lower LPC. Compared to Fagus engleriana, F. hayatae exhibited larger but more sparsely distributed stomata, along with lower resource-acquisition capacity, as reflected in reduced leaf length (LL), LW, LA, SLA, LCC and LNC. Elevation significantly influenced the leaf functional traits of F. hayatae. At lower elevations, the species exhibited increased LA and SLA, while at higher elevations, it adopted more conservative traits, including reduced LA, SLA, stomatal area (SA), and LPC. These patterns highlight F. hayatae’s greater phenotypic plasticity and its reliance on defense-oriented strategies compared to its sympatric congener F. engleriana. Moreover, along elevational gradients, F. hayatae achieved optimal performance at mid-elevations through coordinated stress-tolerance traits. These findings can provide a scientific basis for the conservation and management of this endangered species. Supplementary Material File (article.docx) - Download - 33.14 MB Information & Authors Information Version history Peer review timeline Published Ecology and Evolution Version of Record21 Sep 2025Published Copyright This work is licensed under a Non Exclusive No Reuse License. Collection

Authors Metrics & Citations Metrics Article Usage 242views 232downloads Citations Download citation Tin Pan, Qian Yang, Yan Han, et al. Leaf trait divergence and elevational adaptation in endangered Fagus hayatae: Conservation insights for an East Asian paleoendemic. Authorea. 04 June 2025. DOI: https://doi.org/10.22541/au.174904057.73603001/v1 DOI: https://doi.org/10.22541/au.174904057.73603001/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu.