tailieunhanh - Climate Change and Managed Ecosystems - Chapter 18

Đất ngập nước là một yếu tố đặc trưng của cảnh quan Canada. Họ xảy ra bất cứ nơi nào nguồn cung cấp nước trên bề mặt đất duy trì điều kiện ngập nước và cộng đồng sinh học chuyên ngành bất cứ nơi nào thích nghi với sự khác biệt rõ trong đất oxy giữa các thời kỳ ướt và khô. Các thiết lập địa mạo của đất và tích tụ trầm tích trong các vùng đất ngập nước riêng của mình, đặc biệt là trong trường hợp của than bùn địa mạo, là những yếu tố quan trọng kiểm soát điều kiện nước. | 18 Knowledge Gaps and Challenges in Wetlands under Climate Change in Canada . Warner and T. Asada CONTENTS Common Wetland Classification and Hydrological Landscape Modifications and Water Budget Sedimentation and Water Quality Carbon Cycling and Invasive Wetland Archival Records . 366 Wetland Ecotechnology The Way of the Summary and INTRODUCTION Wetlands are a characteristic element of the Canadian landscape. They occur anywhere supplies of water on the land surface sustain waterlogged conditions and anywhere specialized biotic communities are adapted to extreme variations in soil oxygen between periods of wetness and dryness. The geomorphologic setting of the land and the buildup of sediments in the wetland itself especially in the case of peat landforms are important factors controlling water conditions in wetlands. Climate determines the amount of water that enters via precipitation and leaves via evapotranspiration and more indirectly influences the supply of water that may enter via surface runoff and groundwater seepage. Human activities can affect the supplies of water entering wetlands by physically modifying the natural shape and size of the wetland and its surrounding watershed by drawing water directly from the wetland and the sources supplying it and by altering the vegetation cover which 355 2006 by Taylor Francis Group LLC 356 Climate Change and Managed Ecosystems in turn affects the inputs from and losses to the atmosphere. To understand wetland and climate relationships is to understand relationships between climate and water but these relationships upset the natural balance when human activities interfere and threaten wetlands and their supplies of water. Several reviews demonstrate Canada s considerable progress toward understanding and managing .