Ecological Threats and Agricultural Opportunities of the Aquatic Cane-Like Grass Phragmites australis in Wetlands

Abstract

Wetlands are some of the most biologically productive and dynamic natural ecosystems with multiple value for man and nature. Indeed wetlands provide goods and service such as water storing, floodwater trapping, and trapping of sediment and pollutants. Wetlands also affect climate change by absorbing CO 2 , storing and releasing heat, and harnessing sunlight using a rich variety of vegetation that supports animal life. However wetlands can be polluted by industrial and commercial operations, agricultural runoff and storm water. Wetlands are degraded by filling in and drainage for land development. Wetlands are also degraded by dredging for commercial and recreational water traffic. Dam construction and irrigation roads change the hydrological status of wetlands. Wetlands allow the growth of aquatic macrophytic vegetation such as the emergent Phragmites australis . P. australis is mainly a clonal plant occurring in natural areas. P. australis invasion in wetlands alters the structure and function of the ecosystem by reducing plant and animal biodiversity and changing hydrological regimes and nutrient cycles. This invasion leads to less food or cover for wildlife, decreased use of an area for recreational purposes and decreased availability of drinking and irrigating water. Several methods have been applied in order to control P. australis growth. Control methods include non ecological methods such as burning that releases CO 2 in the atmosphere and chemical control with non-specific herbicides. Control methods include also ecological methods such as grazing and removal of above-ground biomass by cutting. Cuttings can in turn be used for on-farm application as green manure or sludge after energy production and compost production. An economic and ecological basis for accepting a beneficial role for P. australis is lacking. This report focuses on the possibility that people living near wetlands could produce compost using plant material from P. australis . Suitable use of compost in agriculture could reduce the fertilizer application and thereby reduce the environmental pollution, improve food security and soil productivity, and increase sustainability in the agroecosystems. It can also play role in the climate change because part of the organic C is released as CO 2 in the atmosphere and the rest is consumed by the decomposers.