Wetlands, climate change and human disturbance:microscale to macroscale studies

点击翻译按钮获取中文摘要

Wetlands are estimated to cover 4-8% of the land surface of the Earth, which is 2-3 times more than lakes, reservoirs, rivers and other freshwater bodies. The world's wetland soils contain the greatest quantities of carbon, a large proportion of which is in Canadian wetlands (including peatlands). Disturbance by humans is a major environmental problem threatening Canada's wetland and carbon resources and the large economy dependant (directly and indirectly) upon wetlands (ie. food production, horticultural peat industry, water supplies, ecotourism activities, native communities). Wetland disturbances are also closely linked to climate changes. Unfortunately, it is difficult to identify which disturbances are within the natural range of variability and which are due to humans. This research uses paleoecological methods (ie. analysis of pollen, plant macrofossils, testate amoebae, sediment characteristics, C sequestration, age dating) to reconstruct past wetland environments over long (Holocene time) and short (100 years) time frames to assess the nature of change and magnitude of disturbances. This research contributes to resolving controversies about changes in wetlands, whether climate induced soil decomposition in wetlands will have positive feedback to climate change, or conversely, if carbon derived from plant biomass will exceed decomposition, thereby having negative feedback to climate change. Testate amoebae, a large component of wetland microbial communities, are being studied to develop testate amoebae as sensitive biomonitors of whole microbial communities to identify small-scale climate and carbon changes and human impacts. Given that wetlands are a predominant part of the natural landscape in Canada, the information collected in this project will provide protocols for assessing negative environmental disturbances. This information will feed into development of better management plans, environmental and economic policies and regulations, and wetland restoration and rehabilitation efforts currently practiced at local, provincial/territorial, and national levels in Canada.