Ecological stoichiometry of C, N, and P of invasive Phragmites australis and native Cyperus malaccensis species in the Minjiang River tidal estuarine wetlands of China

Abstract

Tidal estuarine wetlands of China are rich in plant diversity, but several global change drivers, such as species invasion, are currently affecting the biogeochemical cycles of these ecosystems. We seasonally analyzed the carbon (C), nitrogen (N), and phosphorus (P) concentrations in litters and soils and in leaves, stems, and roots of the C 3 invasive species Phragmites australis (Cav.) Trin. ex Steud.and of the C 4 native species Cyperus malaccensis var. brevifolius Boeckeler to investigate the effect of C 3 plant invasion on C, N, and P stoichiometry in the C 4 plant-dominated tidal wetlands of the Minjiang River. When averaged across seasons, the invasive species P. australis had higher N concentrations and lower P concentrations in leaves than the native species C. malaccensis. N and P concentrations were lower in litter (stem and leaf), whereas C concentrations in leaf litter were higher in P. australis than in C. malaccensis. The C, N, and P concentrations of the soil also did not differ, but plants had a lower C:N and much higher N:P ratios than soils. Root C:P and N:P ratios were lower in the growing season both in the invasive and the native species. The leaf C:N, C:P and N:P ratios peaked in summer. The invasive species had lower C:N ratio in leaves and roots, and higher N:P ratios in all biomass organs and litter than the native species, an effect related with the higher N-resorption capacity of the invasive species. Interspecific differences in C:N, C:P, and N:P ratios may likely reflect the differences in plant morphology, nutrient-use efficiency, and photosynthetic capacity between the C 3 (P. australis) and C 4 (C. malaccensis) plants. Our results generally suggested that the success of P. australis in these wetlands was related to its slow growth and higher resorption capacity of N and P. This implies a more conservative use of limited nutrients, particularly N, by P. australis, and to higher N concentration in its biomass thus potentially contributing to its invasiveness in these estuarine wetlands.Communicated by William E Rogers.Electronic supplementary material The online version of this article

Typhoon enhancement of N and P release from litter and changes in the litter N:P ratio in a subtropical tidal wetland

“…Nutrient limitation is especially significant in tidal wetlands, likely because the periodic inundation of the soil limits the access of plants to soil nutrients by the anoxic effects on root growth (Amlin andRood 2001, Kirwan andGuntenspergen 2012), by slowing The N-limitation of this wetland is also evident by its soil N:P ratio (4.4 on a molar basis) (Wang et al 2014), which is much lower than the average of 28 for various wetlands around the world (Xu et al 2013). Previous studies in Mnjiang River estuarine wetlands have observed a general N-limitation in the tall-grasses communities (Wang et al 2015a(Wang et al , 2015b.…”

Factors Related with CH4 and N2O Emissions from a Paddy Field: Clues for Management implications

“…Soil denitrification, however, could become dominant under such conditions, and most of the intermediate products (i.e. NO and N 2 O) could be reduced to the final product N 2 , especially in N-limited areas such as our study site[61] where N 2 O emission can be negative (Fig 2). Van Rijn[62], however, reported that denitrification in soils with a high Eh could become a dominant microbial process that promotes N 2 O production but inhibits methanogenic activity.…”

Interspecific competition changes nutrient : nutrient ratios of weeds and maize

“…The differences in elemental ratios among maize, B. pilosa, A. viridis , and I. grandifolia are probably due to the intrinsic morphophysiological characteristics of these species. As proposed by Wang et al (), interspecific differences in elemental ratios, such as C : N, C : P, and N : P, may reflect differences in plants morphology, nutrient use efficiency, and photosynthetic capacity, as observed for Phragmites australis and Cyperus malaccensis . The increase in the C : N ratio of B. pilosa and I. grandifolia tissues in response to coexistence with maize are probably due to physiological and genetic adjustments of these weeds to competition.…”

“…The differences in elemental ratios among maize, B. pilosa, A. viridis, and I. grandifolia are probably due to the intrinsic morphophysiological characteristics of these species. As proposed by Wang et al (2015), interspecific differences in elemental ratios, such as C : N, C : P, and N : P, may reflect , and Ipomoea grandifolia (Ig) grown for 60 d in monoculture or in interspecific competition. Different letters within maize nutrient : nutrient ratios indicate significant differences between means based on Tukey's test (P < 5%).…”