Leaf nitrogen and phosphorus stoichiometry of plant communities in geochemically phosphorus-enriched soils in a subtropical mountainous region, SW China

Abstract

Leaf nitrogen (N) and phosphorus (P) stoichiometry might reflect the biogeochemical features of ecosystems, yet the potential range of stoichiometric flexibility under geochemically P-enriched soils (GPES) is still unclear. Leaf N and P of 126 plant species in 70 vegetation plots in GPES were investigated in central Yunnan, southwestern China, and leaf P fractions (i.e., inorganic vs. organic P) of the dominant species were examined. Our objectives were to improve the understanding of the role of soil N and P variability in controlling leaf N and P stoichiometry of plant communities in GPES. We found that plants in GPES had higher mean leaf P (4.07 mg/g) and lower N:P ratios (4.94) than average plant values that have been recorded in other parts of the world so far. Some fastgrowing plants had extremely high leaf P ([10 mg/g).Community leaf N and P contents increased as soil N availability increased, but soil N variability was unrelated to community leaf N:P. Instead, community leaf P and N:P ratios were primarily determined by soil P; as soil P availability increased, leaf P increased and leaf N:P significantly decreased. Greater accumulation of inorganic P relative to organic P in leaf was the direct driving factor for community leaf P and N:P ratio patterns in GPES. Although soil P availability was the main controlling factor of leaf N:P patterns, community composition could be manipulated to restore the balance of N and P stoichiometry based on the different responses across species and plant types.

Current re-vegetation patterns and restoration issues in degraded geological phosphorus-rich mountain areas: A synthetic analysis of Central Yunnan, SW China

“…Our examination of these GPR regions show that (1) the vegetation in these areas suffer from high levels of degradation; (2) soil N and P nutrient levels are unbalanced; (3) there are significant impacts from invasive species; (4) excess high soil P content and low soil N: P ratios could result in P-toxicity for some species and hinder plants survival ( Shane and Lambers, 2006 ; Matheny et al., 2016 ). These findings indicate an urgent need to deal with the issues of vegetation degradation, soil nutrition balance, and invasive species ( Guariguata et al., 1995 , Yan et al., 2015 , Yan, 2015 ).…”

“…The central Yunnan region in China is one of the four largest sedimentary phosphate deposits in the world, alongside Khouribga in Morocco, Florida in America, and Kola in Russia. Around 15% of China's total phosphorus ore deposits are located in the region ( Zapata and Roy, 2004 , Li et al., 2015c , Yan et al., 2015 ). The major river systems in the central Yunnan region are the Yangtze, Pearl and Red Rivers.…”

“…The main soil types found in our study area were Ferralsols and Cambisols. Soil P concentrations were high and variable, the total P ranged from 0.5 to 87.4 g/kg, and available P varied from 39.6 to 748.7 mg/kg ( Yan et al., 2015 ). In recent decades, human activities such as mining and farmland reclamation have led to severe degradation of vegetation, especially in the GPR mountainous region.…”

Shrub modulates the stoichiometry of moss and soil in desert ecosystems, China

“…For example, the ratio of N:P and the N and P contents in leaves of desert plants in most desert ecosystems in China (Zheng and Shangguan, 2007;Zhang et al, 2014;Tao et al, 2016) are higher than those in other ecosystems in China (Han et al, 2005) or globally (Elser, 2000;Reich and Oleksyn, 2004), which reveals differences in plant nutrient limitation and soil nutrient supply potential (Sardans et al, 2011(Sardans et al, , 2012He et al, 2014;Wu et al, 2014;Tao et al, 2016). Soil stoichiometry is significantly correlated to plant growth, and directly influence the composition, structure and productivity level of ecological communities (Andersen et al, 2010;Yan et al, 2015). Previous studies have greatly advanced our understanding of the variations and patterns of N and P in leaves of vascular plants in desert ecosystems.…”

Caution Is Needed in Quantifying Terrestrial Biomass Responses to Elevated Temperature: Meta-Analyses of Field-Based Experimental Warming Across China

“…Meanwhile, field-based experiments concerning woody plants are still limited, especially for trees; this reduces the credible projection of our research regarding the climate-terrestrial C response in China. Moreover, research should also be undertaken to investigate the responses of special plants like relic species [23,29], invasive species [25,30], agroforestry trees [31,32], and plants living in special geological environments [17,33], often regarded in the investigation of ecosystem services for humanity, but for which field-based warming experiments are still limited. Finally, as we have mentioned, plant communities and their dominant species do not always show a constant response, and so to develop a full picture of warming-induced responses of plant biomass and C sequestration, additional long-term warming experiments regarding community stability [24], interspecific relations [30], functional diversity and evolution [13,16,18], etc., will be needed.…”