Community Characteristics and Leaf Stoichiometric Traits of Desert Ecosystems Regulated by Precipitation and Soil in an Arid Area of China

Abstract

Precipitation is a key environmental factor determining plant community structure and function. Knowledge of how community characteristics and leaf stoichiometric traits respond to variation in precipitation is crucial for assessing the effects of global changes on terrestrial ecosystems. In this study, we measured community characteristics, leaf stoichiometric traits, and soil properties along a precipitation gradient (35–209 mm) in a desert ecosystem of Northwest China to explore the drivers of these factors. With increasing precipitation, species richness, aboveground biomass, community coverage, foliage projective cover (FPC), and leaf area index (LAI) all significantly increased, while community height decreased. The hyperarid desert plants were characterized by lower leaf carbon (C) and nitrogen/phosphorus (N/P) levels, and stable N and P, and these parameters did not change significantly with precipitation. The growth of desert plants was limited more by N than P. Soil properties, rather than precipitation, were the main drivers of desert plant leaf stoichiometric traits, whereas precipitation made the biggest contribution to vegetation structure and function. These results test the importance of precipitation in regulating plant community structure and composition together with soil properties, and provide further insights into the adaptive strategy of communities at regional scale in response to global climate change.

Spatial variation in leaf nutrient traits of dominant desert riparian plant species in an arid inland river basin of China

“…In arid terrestrial ecosystems, scarce precipitation causes poor soil leaching, low loss of P from soil weathering, and a low biodiversity level and vegetation cover, leading to soil P content being relatively abundant compared to soil N content, which could explain why nitrogen is more likely to be the key limiting factor in desert ecosystems (Vitousek & Howarth, ; Vitousek, Porder, Houlton, & Chadwick, ). These results were also confirmed by our results (Zhang et al, ) and those of other studies (Vitousek et al, ; Wang et al, ; Wang, Yang, & Ma, ). Previous studies on the different ecosystems suggest that leaf N/P < 14 demonstrates N limitation, leaf N/P > 16 demonstrates P limitation, and 14 < leaf N/P < 16 indicates either N or P limitation, or both (Aerts & Chapin, ; Koerselman & Meuleman, ).…”

“…In the lower reaches of Heihe River, our result showed that the average leaf C of the dominant species was 327.29 mg/g (Supporting Information Table ), and lower than the mean values of global flora and of Loess Plateau (Elser, Fagan, et al, ; Zheng & Shangguan, ). Leaf N and leaf P were lower than that in the Gobi desert region of the Heihe River, and lower than the mean values of global flora and of other arid and semiarid regions (Reich & Oleksyn, ; Wang et al, ; Zhang et al, ; Zheng & Shangguan, ). However, leaf C/P and leaf N/P were higher than that in other regions (Han et al, ; Reich & Oleksyn, ; Wang et al, ; Zheng & Shangguan, ).…”

“…Plant leaves, as the main organs of photosynthesis, play a key role in determining plant survival and productivity in ecosystems, and their nutrient traits, including leaf carbon, leaf nitrogen, leaf phosphorus, and leaf potassium, are closely related to the structure and function of ecosystems (Güsewell, ; Wright et al, ). In arid regions, water conditions (e.g., precipitation) may alter the leaf nutrient traits, mainly through plant–soil feedback, and the leaf nutrient traits also change according to differences in species composition (Wang et al, ; Zhang et al, ). Leaf decomposition and nutrient uptake and assimilation drive biogeochemical cycling to a certain degree, and these processes of resource investment and reinvestment are inherently survival strategies adapted to a chronic drought environment for plants in arid areas (Drenovsky & Richards, ; Simões, Calado, Madeira, & Gazarini, ).…”

“…In arid regions, water conditions (e.g., precipitation) may alter the leaf nutrient traits, mainly through plant-soil feedback, and the leaf nutrient traits also change according to differences in species composition (Wang et al, 2015;Zhang et al, 2018a). Leaf decomposition and nutrient uptake and assimilation drive biogeochemical cycling to a certain degree, and these processes of resource investment and reinvestment are inherently survival strategies adapted to a chronic drought environment for plants in arid areas (Drenovsky & Richards, 2004;Simões, Calado, Madeira, & Gazarini, 2011).…”

“…observed that plants survive in a relatively wide range of nutrient contents in terrestrial ecosystems, and the concentrations of C, N, P, and their stoichiometric ratios within plants to an extent reflect how a plant has adapted to the local habitat (Elser, Fagan, Kerkhoff, Swenson, & Enquist, 2010). Previous studies on arid and semiarid regions suggest that plant growth is mainly limited by the N element (Wang et al, 2015;Zhang et al, 2018a), but in other studies, P-limited growth has also been detected (Zheng & Shangguan, 2007). These differences may be due to differences in nutrient limitations in different areas (Zhao et al, 2014).…”