Change in ecological stoichiometry of Carex brevicuspis in response to sampling time and elevation in Dongting Lake, China
20 March 2018
Fu, Hua; Feng, Li; zhu, lian; Xie, Yonghong; hu, cong; Chen, Xinsheng; deng, miaoPlant nutrient stoichiometry is affected by both environmental factors and plant physiological processes. However, we know little about how elevation gradients and seasonality combine with soil physicochemical properties to influence nutrient stoichiometry. In this study, we examined these factors in the wetland plant Carex brevicuspis in Dongting Lake, China, during the non-flooding periods in March, May, and December of 2015 and February of 2016. We obtained the following results. Total foliar C concentration increased as elevation increased, especially during December 2015 and February 2016. At the low-elevation site, total foliar C concentration decreased over time, whereas it first increased and then decreased over time at higher elevations. Foliar total N and P concentrations decreased from March to May and subsequently increased over time. Their values remained much higher at the low-elevation site. The C:N and C:P ratios first increased and then decreased over time, while increasing with rising elevation. The N:P ratio was lower at the low-elevation site, especially during May 2015 and February 2016; its variation over time differed across the elevations. A canonical correspondence analysis revealed that soil organic C, total N, and soil nitrate N are important for determining C. brevicuspis stoichiometry. These results indicated that both elevation and plant life stage have a significant influence on plant stoichiometry. This study improves our understanding of seasonal dynamics of plant nutrients under different geographical conditions.