Estimating the biomass of Carex cinerascens (Cyperaceae) in floodplain wetlands in Poyang Lake, China

Abstract

The estimation of wetland plant biomass is key to understanding the dynamic changes of the structure and functions of wetland ecosystems. Relatively few studies on the spatiotemporal dynamics of wetland plant biomass have been conducted because of the difficulties in obtaining detailed and accurate data. Carex cinerascens meadows are important patches in Poyang Lake in eastern China and provide significant food resources and habitats for wintering waterbirds, particularly geese. We proposed a method to estimate the biomass of C. cinerascens in a subsection of Poyang Lake, i.e. Baisha Lake, employing the digital elevation model and water level gradient of the lake combined with the logistic regression model based on data from field measurements in different elevations. We obtained four C. cinerascens biomass estimation models based on four elevations divided. The maximum biomass decreased with decreasing elevation. Meanwhile, the maximum growth rate initially increased and subsequently decreased. The biomass of C. cinerascens per unit area ranged from 0.10 to 0.58 kg/m² in the autumn and winter. Significant differences in the growth process of C. cinerascens were observed in different water level gradients. The total biomass of C. cinerascens in Baisha Lake changed following an S-shaped curve and reached 221, 503, and 615 t in the middle of October, November, and December, respectively. The research results can be used to forecast the biomass of C. cinerascens under different hydrological conditions in Poyang Lake, and to provide wetland plant biomass estimation methods for other similar regions.

Keywords:

• Biomass estimation
• logistic model
• water level gradient
• Poyang Lake

Acknowledgments

We thank the Poyang Lake Nanji Wetland National Nature Reserve for providing support and accommodation at the experiment site. We thank Dr. Jiaxing Zu, a PhD candidate at Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences for the help of mapping the sampling sites figure.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Ya Li is currently a PhD for research on wetland monitoring and biogeochemistry at Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences.

Xiubo Yu is the research program leader in Poyang Lake wetland ecology, and a researcher of Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences. He is currently a coordinator of Ecosystem Monitoring and Capacity Building at UNEP International Ecosystem Management Partnership.

Qun Guo is currently a research assistant of Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences and specialized in grassland productivity.

Yu Liu is an associate research fellow of Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences and specialized in the trade-off of wetland ecological service.

Shaoxia Xia is currently a research assistant of Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences and specialized in wetland ecology and ecological service.

Guangshuai Zhang is currently a research assistant of National Marine Environmental Monitoring Center, People’s Republic of China, and a PhD of Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences.

Quanjun Zhang is currently a PhD candidate for research on wetland monitoring and biogeochemistry at Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences.

Houlang Duan is currently a PhD candidate for research on wetland monitoring at Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences.

Liang Zhao is currently a Master Degree Candidate in Chengdu University of Technology.

Additional information

Funding

The research was financially supported by the Research and Development of Composite Model in Poyang Lake Water Ecology. This work was supported by National Natural Science Foundation of China (41471088).