tailieunhanh - Handbook of Ecological Indicators for Assessment of Ecosystem Health - Chapter 8

Áp dụng các chỉ số sinh thái cho Y tế Đánh giá hệ sinh thái biển 8,1 GIỚI THIỆU "bánh xe đẩy, ngươi sâu và màu xanh đại dương - cuộn! Mười ngàn đội tàu quét trên ngươi vô ích; Man đánh dấu Trái đất với hủy hoại - kiểm soát của mình dừng lại với bờ biển, Lord Byron đã viết cách đây 200 năm. Đã xảy ra nhiều từ, và con người tác động đến môi trường biển đến một mức độ lớn hơn nhiều so với suy nghĩ có thể nhiều thế kỷ hoặc thậm chí nhiều thập. | CHAPTER 8 Application of Ecological Indicators for Assessing Health of Marine Ecosystems Villy Christensen and Philippe Cury INTRODUCTION Roll on thou deep and dark blue ocean roll Ten thousand fleets sweep over thee in vain Man marks the Earth with ruin his control stops with the shore Lord Byron wrote two hundred years ago. Much has happened since and humans now impact the marine environment to an extent far greater than thought possible centuries or even decades ago. The impact comes through a variety of channels and forcing factors. Eutrophication and pollution are examples and while locally they may be important they constitute less of a direct threat at the global scale. A related issue global warming and how it may impact marine ecosystem may be of more concern in the foreseeable future. This is however presently being evaluated as part of the Millennium Ecosystem Assessment 69 to which we will refer for further information. Copyright 2005 by Taylor Francis Habitat modification especially of coastal and shelf systems is of growing concern for marine ecosystems. Mangroves are being cleared at an alarming rate for aquaculture removing essential habitat for juvenile fishes and invertebrates coastal population density is exerting growing influence on coastal systems and bottom trawls perform clear-cutting of marine habitat drastically altering ecosystem form and functioning. The looming overall threat to the health of marine ecosystems however is the effect of overfishing 2 and this will be the focus of the present contribution. We have in recent years witnessed a move from the perception that fisheries resources need to be developed by expanding the fishing fleet toward an understanding that the way we exploit the marine environment is bringing havoc to marine resources globally endangering the very resources on which a large part of the human population rely for nutrition. Perhaps most alarming in this development is that the global fisheries production .