Variation in species assemblages due to micro-topography and flow regime govern vegetation carbon stock in seasonal floodplain wetlands

Priyanka Sarkar,Tapati Das,Dibyendu Adhikari

doi:10.1186/s13717-019-0201-9

Priyanka Sarkar, Tapati Das + Show 1 more

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https://doi.org/10.1186/s13717-019-0201-9

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Abstract

HypothesisVariation in species assemblages due to micro-topographic features and flow regime determine vegetation carbon stock in floodplain wetlands.Material and methodWe tested this hypothesis in Chatla—a tropical floodplain wetland located in northeast India. Five sampling stations characterized by contrasting micro-topographic and flow parameters were selected in the wetland for study. Species composition, assemblage pattern, and vegetation carbon stock were studied in these stations during three flood phases, i.e., early, middle, and late flood phases following standard methods. Univariate and multivariate statistics were used to determine the relationship between the selected environmental parameters, plant species assemblages, and vegetation carbon stock of the wetland.ResultsThirty-one species of herbs and five species of shrubs were recorded from the five stations in Chatla floodplain wetland. Flow regime characterized by water flow velocity and discharge showed substantial variations across the stations. These parameters in turn are related to variations in the micro-topographic characteristics namely depth, width, and cross-sectional area of the stations. Plant species composition and abundance differed significantly with respect to micro-topography and flow regime as revealed by the cluster diagram. The canonical correspondence analysis revealed strong association of plant species assemblages with the micro-topography and flow regime within the wetland. Multiple regression analysis revealed a significant positive relationship of the vegetation carbon stock with the water discharge.ConclusionsSpatial variation in plant species diversity because of micro-topography and flow regime determines the vegetation carbon stock in floodplain wetlands. Modification of these parameters by anthropogenic activities such as mining and quarrying may potentially influence the carbon stocking potential of seasonal floodplain wetlands. Therefore, appropriate measures should be taken to maintain the integrity of the natural topographic features of such wetlands.

Highlights

Tropical floodplain wetlands provide numerous ecological services through regulation of hydrological cycle, facilitation of groundwater recharge, controlling flood risk by modifying the river discharge, and support diverse livelihood activities (Costanza et al 1997; Tockner and Stanford 2002; Murphy et al 2003; Mitsch and Gosselink 2015)
Flow regime characterized by water flow velocity and discharge showed substantial variations across the stations
Appropriate measures should be taken to maintain the integrity of the natural topographic features of such wetlands

Summary

Introduction

Tropical floodplain wetlands provide numerous ecological services through regulation of hydrological cycle, facilitation of groundwater recharge, controlling flood risk by modifying the river discharge, and support diverse livelihood activities (Costanza et al 1997; Tockner and Stanford 2002; Murphy et al 2003; Mitsch and Gosselink 2015). They are one of the most carbon-rich ecosystems storing ~ 250 Gt of carbon (Neue et al 1997; Bernal and Mitsch 2013; Kolka et al 2016). To design and implement effective management strategies, it is necessary to understand how the proximal abiotic factors influence the pattern and mechanism of carbon stocking in tropical wetlands (Mitra et al 2005; Kolka et al 2016)

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