Spatial patterns and variations in leaf traits of alpine plants on the interior Tibetan Plateau

Abstract

Spatial patterns and environmental gradients in plant traits can elucidate the relationships between plant characteristics, environmental factors, and ecosystem functions and can be used to develop the next generation of vegetation models for predicting vegetation distribution and functions. Studies of Plant traits across spatial scales have advanced significantly worldwide, including on the Tibetan Plateau (TP), the highest and largest plateau globally. Previous research on plant traits on the TP has been limited to specific areas, leaving the overall trend across the plateau unclear. In this study, we examined seven leaf traits—leaf thickness (LT), leaf dry matter content (LDMC), leaf area (LA), specific leaf area (SLA), and leaf carbon (LCC), nitrogen (LNC), and phosphorus (LPC) contents—in 1314 individuals at 237 sites within the alpine vegetation region above 3000 m on the TP to determine their distribution patterns across three spatial dimensions and their relationships with environmental factors. Our results indicated that, compared with Chinese plants, TP plants exhibited significantly greater LT, LDMC, and LNC but lower LA, LCC, and LPC. Except for SLA and LCC, most leaf traits showed significant spatial variability. Climate and soil explained 29.23 % of the total variations in traits. Radiation had the most pronounced effect on LDMC, LA, LNC, and LPC, whereas soil pH primarily constrained LT and LCC. Precipitation influenced most traits both directly and indirectly, with substantial overall effects. Temperature and soil nutrient had minimal influence on the regulation of leaf traits across most of the TP. Our findings suggest that alpine plants typically employ a conservative strategy to cope with the harsh conditions on the TP, but this strategy varies at broader spatial scales and longer environmental gradients, particularly in extreme environments such as the highest alpine regions.