tailieunhanh - Lake Trout Ecosystems in a Changing Environment - Chapter 15

Mô hình và các vấn đề liên quan đến quản lý hệ sinh thái Biến đổi khí hậu và khai thác bền vững hồ cá hồi: dự đoán từ một mô hình lịch sử khu vực của cuộc sống Một số tác giả có giải quyết các tác động tiềm tàng của biến đổi khí hậu trên hồ cá hồi Salvelinus namaycush từ quan điểm khá khác nhau. Schindler (1998) và đồng nghiệp (1996) xác định một loạt các yếu tố (ví dụ, làm tăng tiếp xúc với gió do. | section IV Models and issues associated with ecosystem management 2004 by CRC Press LLC chapter fifteen Climate change and sustainable lake trout exploitation predictions from a regional life history model Brian J. Shuter Ontario Ministry of Natural Resources Nigel P. Lester Ontario Ministry of Natural Resources Contents Introduction A regional model for lake trout populations Observed variation in lake trout life histories Environmental variation life history variation and the parameters of a population harvest model Life history variation and variation in sustainable exploitation rates and sustainable harvests Potential impacts of climate change on sustainable harvests and exploitation rates References Introduction Several authors have recently addressed the potential impacts of climate change on lake trout Salvelinus namaycush from quite different perspectives. Schindler 1998 and coworkers 1996 identified a variety of factors . increased wind exposure due to forest fires increased water clarity due to DOC reductions that could shrink hypolimnetic summer refuge habitats for lake trout particularly in smaller lakes and thus negatively affect population sustainability. Magnuson et al. 1990 1997 and Magnuson and DeStasio 1997 looked at likely changes in the amount of habitat thermally suitable for lake trout and concluded that this factor alone would only lead to negative effects in shallow lakes largely through increases in summer temperatures. Stefan et al. 2001 modeled changes in the annual temperature 2004 by CRC Press LLC and oxygen regimes typical of small lakes in the continental United States and concluded that climate warming would produce significant contraction of usable habitat for many populations of coldwater fish . fish species with the low-temperature and high-oxygen requirements typical of lake trout Ryan and Marshall 1994 . As surface waters warm and longer stratification periods produce anoxia in deeper waters usable habitat for lake trout .