Intraspecific variations in leaf traits, productivity and resource use efficiencies in the dominant species of subalpine evergreen coniferous and deciduous broad‐leaved forests along the altitudinal gradient

Abstract

Many studies have reported intraspecific variations in leaf functional traits, but their contribution to plant performance and ecosystem function are poorly understood. We studied altitudinal gradients of intraspecific variations in leaf traits, productivity and resource use efficiency in the dominant species of subalpine evergreen coniferous and deciduous broad‐leaved forests in Japan. We addressed three hypotheses, which are exclusive to each other. (1) Leaf traits vary along the leaf economics spectrum (LES). Plants that grow at lower and higher altitudes have fast‐ and slow‐return strategies, respectively, which improve productivity or resource use efficiency in the respective habitat. (2) Leaf trait variations are not consistent with the LES, but they contribute to improving productivity or resource use efficiency in the respective habitat. (3) Leaf trait variations do not contribute to improving productivity or resource use efficiency at higher altitudes. On the studied mountain range, Fagus crenata, a deciduous broad‐leaved tree, and Abies mariesii, an evergreen conifer, are the dominant species at lower and higher altitudes respectively. In F. crenata, leaf mass per area (LMA) and nitrogen concentrations were higher at higher altitudes. The net assimilation rate and light use efficiency during the growing season were greater at higher altitudes, which compensated for the shorter growing season in terms of annual productivity. In A. mariesii, the LMA was lower and the leaf life span was unchanged at higher altitudes. Productivity and resource use efficiency decreased with altitude. Synthesis. We conclude that F. crenata improves its productivity and resource use efficiency at higher altitudes by altering its leaf functional traits (Hypothesis 2), whereas alterations to leaf traits in A. mariesii are not associated with any improvement at higher altitudes (Hypothesis 3), which may result from the negative impact of environmental stress. Hence, the ecological significance of altitudinal variations in leaf traits depends on species and environment.

Adaptation of Abies fargesii var. faxoniana (Rehder et E.H. Wilson) Tang S Liu seedlings to high altitude in a subalpine forest in southwestern China with special reference to phloem and xylem traits

“…The result is reinforced by the fact that leaf δ 13 C (water use efficiency, Farquhar et al 1989) was significantly different among altitudes, with the greates values at 3200 m, suggesting that plants show acclimation to drying by freezing and low temperature at subalpine treelines in spite of greater water availability (Li et al 2004). Hikosaka et al (2021) showed that leaf N based on the area in Fagus crenata increases at higher altitudes, whereas leaf N did not change with increasing altitude in the present study, indicating that N limitation may not play a key role in the growth of A. fargesii at treeline. In our study, main stem diameter showed an increasing trend with increasing altitudes, but there was a reduction in tree height with increasing altitudes, which might be due to the low temperature that suppressed meristematic growth of primary meristems (Körner 2003).…”

Functional traits of a plant species fingerprint ecosystem productivity along broad elevational gradients in the Himalayas

“…Higher SLA and N concentration modulate a faster resource acquisition at lower elevation than at higher elevation with decreasing leaf N concentration and SLA, consequently altering the primary productivity (Reich, 2014). It was also supported by studies along elevation gradients (Hikosaka et al, 2021) and in tropical and temperate forests (He et al, 2019). Functional trait diversity is considered as an integrative metric to explore GPP from tropical to cold-temperate forests in Eastern China (Li, Hou, et al, 2022).…”

“…Traits related to plant morphology, physiology and phenology influence the fitness of species (Niu et al, 2018; Read et al, 2014), and reflect adaptive responses to abiotic and biotic conditions (Kattge et al, 2011; Midolo et al, 2019). Moreover, trait divergence can also be used to gain insights into functional ecology and biogeography (Bolnick et al, 2011; Kattge et al, 2011; Reichstein et al, 2014), ecosystem productivity (Cui et al, 2019; Hikosaka et al, 2021), reproductive phenology (Liu et al, 2021), patterns of biodiversity (Li, Liu, et al, 2022; Violle et al, 2012), water–energy dynamics (Blonder et al, 2020; Lu et al, 2022; O'Brien, 2006) and responses to climate change (Li et al, 2020; Westerband et al, 2021).…”

Precipitation and soil nutrients determine the spatial variability of grassland productivity at large scales in China

“…There were significant spatial differences in NPP of different grassland types, and the NPP of AM was significantly higher than that of DS. Significant differences in NPP were closely related to habitat heterogeneity (Hikosaka et al, 2021). Due to the differences in biological or abiotic factors in different regions, there are significant differences in NPP of grassland in different regions (Li et al, 2019).…”

“…Leaf traits are widely used to detect the adaptability of plants to the living environment (Hikosaka et al, 2021). The traits we selected included LA, SLA, LDMC, LN, LP, and leaf N/P ratio.…”