湿地生态学英文.ppt

湿地生态学英文第一页，共三十页，2022年，8月28日 Topics covered in this lectureWetland status and trends, causes of losses.Definitions and criteria used to identify and delineate wetlands.Wetlands functions and values.Overarching theme: the interplay of science, public policy and natural resource values第二页，共三十页，2022年，8月28日 The way that wetlands are viewed has evolved over time:During settlement of the U.S., wetlands were considered “bug-infested, disease- ridden wastelands that impeded settlement and economic development.第三页，共三十页，2022年，8月28日 Federal policies toward wetlands has evolvedfrom policies and programs that encourageddrainage and filling of wetlands……第四页，共三十页，2022年，8月28日 第五页，共三十页，2022年，8月28日 …. to a federal policy of “no net loss” of wetlands, including subsidy and technical assistance to restore and create wetlands.第六页，共三十页，2022年，8月28日 第七页，共三十页，2022年，8月28日 Estimated rate of wetlands loss 1950s – 1990sWetlands Status and Trends 2000458,000Average annual net wetland loss for the conterminous United States1950s – 70s1980s – 90s1970s – 80s290,00058,500Acres第八页，共三十页，2022年，8月28日 第九页，共三十页，2022年，8月28日 第十页，共三十页，2022年，8月28日 第十一页，共三十页，2022年，8月28日 第十二页，共三十页，2022年，8月28日 The way that wetlands are viewed has evolved over time:The public, especially user groups, began to recognize the resource values of wetlands.Concern began to grow in the 1950’s and 1960’s over an alarming rate of wetland loss in the U.S.Consequently, appreciation of wetlands increased…”don’t it always seem to go you don’t know what you’ve got ‘til its gone”—Joni Mitchell, Big Yellow Taxi第十三页，共三十页，2022年，8月28日 More recent programs and legislation provide indirect protection and incentives toconserve and restore wetlands;Section 404 of the Clean Water ActConservation provisions of the 1985-2000 Farm Bills (Food Security Acts)Coastal Zone Management ActNo net loss policies (executive orders)North American Wetlands Conservation Act第十四页，共三十页，2022年，8月28日 Wait a minute…what are wetlands anyway?Until the 1980’s, wetlands were mo