Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download chapter11 2009
Document related concepts
no text concepts found
Transcript
Sustaining Aquatic Biodiversity Chapter 11 Loss of biodiversity and cichlids Nile perch: deliberately introduced Frequent algal blooms Nutrient runoff Spills of untreated sewage Less algae-eating cichlids A Biological Roller Coaster Ride in Lake Victoria Natural Capital Degradation: The Nile Perch What Are the Major Threats to Aquatic Biodiversity? Aquatic species are threatened by habitat loss, invasive species, pollution, climate change, and overexploitation, all made worse by the growth of the human population. We Have Much to Learn about Aquatic Biodiversity Greatest marine biodiversity Coral reefs Estuaries Deep-ocean floor Biodiversity is higher Near the coast than in the open sea In the bottom region of the ocean than the surface region, greater variety of habitats Human Activities Are Destroying Habitats Habitat loss and degradation - HIPPCO Marine – only 4% of the world’s oceans are not affected by pollution Coastal Ocean floor: effect of trawlers, which drag huge nets weighted with heavy chains and steel plates, reduce coral reefs to rubble Freshwater Dams Excessive water withdrawal Invasive species Threaten native species Disrupt and degrade whole ecosystems Water hyacinth: Lake Victoria (East Africa) Asian swamp eel: waterways of south Florida Purple loosestrife: indigenous to Europe Treating with natural predators—a weevil species and a leaf-eating beetle— Invasive Species Are Degrading Biodiversity Invasive water hyacinth How Carp Have Muddied Some Waters Lake Wingra, Wisconsin (U.S.): eutrophic, excessive nutrient inputs from run off with fertilizers from farms/lawns Contains invasive species Purple loosestrife and the common carp, which devour the algae Dr. Richard Lathrop Removed carp from an area of the lake This area appeared to recover Population Growth and Pollution Can Reduce Aquatic Biodiversity Nitrates and phosphates mainly from fertilizers enter water Leads to algal bloom and eventual eutrophication, fish die offs Toxic pollutants from industrial and urban areas, plastic items Hawaiian Monk Seal Climate Change Is a Growing Threat Global warming: sea levels will rise and aquatic biodiversity is threatened – in the past 100 years , average 10-20 cm and scientists estimate another 18-59 cm, perhaps as high as 1-1.6 m ◦ Coral reefs ◦ Swamp some low-lying islands ◦ Drown many highly productive coastal wetlands New Orleans, Louisiana, and New York City Overfishing and Extinction Marine and freshwater fish Threatened with extinction by human activities more than any other group of species Commercial extinction – industrialized fishing fleets can deplete marine life at a much faster rate. Can cause 80% in 10-15 years Collapse of the cod fishery of the coast of Newfoundland and its domino effect leading to collapse of other species Bycatch – seals, dolphins. 34% of marine, 71% of fresh water species face extinction within your life time. 900,000 800,000 700,000 Fish landings (tons) 600,000 500,000 400,000 1992 300,000 200,000 100,000 0 1900 1920 1940 1960 Year 1980 2000 Fig. 11-6, p. 254 Protecting and Restoring Mangroves Protect and restore mangroves Reduce the impact of rising sea levels Protect against tropical storms and tsunamis Cheaper than building concrete sea walls Mangrove forests in Indonesia Industrial Fish Harvesting Methods are vacuuming the seas Trawler fishing- shrimp, scallops Purse-seine fishing tuna, mackarel Longlining – tuna, swordfish, sharks Drift-net fishing – 1992 ban on the use of drift nets longer than 2.5 km Protect and Sustain Marine Biodiversity.. We can help to sustain marine biodiversity by using laws and economic incentives to protect species, setting aside marine reserves to protect ecosystems, and using community-based integrated coastal management. Legal Protection of Some Endangered and Threatened Marine Species Why is it hard to protect marine biodiversity? Human ecological footprint and fish print are expanding Much of the damage in the ocean is not visible The oceans are incorrectly viewed as an inexhaustible resource that can absorb an almost infinite amount of waste Most of the ocean lies outside the legal jurisdiction of any country Treaties - CITES, Marine Mammal Protection Act, Endangered Species Act, Whale Conservation and Protection Act, International Convention on Biological Diversity Protecting Whales: Success Story… So Far Cetaceans: Toothed whales and baleen whales 1946: International Whaling Commission (IWC) – set annual quotas 1970: U.S. Stopped all commercial whaling Banned all imports of whale products 1986: moratorium on commercial whaling Japan ,Norway, Iceland, Russia do not support the IWC ban Norwegian Whalers Harpooning a Sperm Whale Economic Incentives Can Be Used to Sustain Aquatic Biodiversity Tourism – example : sea turtles, worth more to local communities alive than dead (WWF) Economic rewards Holding Out Hope for Marine Turtles(6 out of 7 endangered) Carl Safina, Voyage of the Turtle ◦ Studies of the leatherback turtle Threats to the leatherbacks ◦ ◦ ◦ ◦ Trawlers destroy coral reefs which is their feeding grounds Entangled in fishing nets and lines Pollution –discarded plastic bags Climate change- rising sea levels will flood nesting and feeding areas Communities protecting the turtles Turtle Excluder Devices on shrimp boats An Endangered Leatherback Turtle is Entangled in a Fishing Net Marine Sanctuaries Protect Ecosystems and Species Offshore fishing extends to 370 kilometers Exclusive economic zones-can take certain quotas of fish High seas-beyond legal jurisdiction of any country Law of the Sea Treaty – world’s coastal nations have jurisdiction over 36% of the ocean surface and 90% of the world’s fish stocks Marine Protected Areas (MPAs) – 4000 world wide, 200 in US waters Ecosystem approach to sustainability Marine Commercial fishing Dredging reserves Mining and waste disposal Core zone No human activity allowed Less harmful activities allowed E.g., recreational boating and shipping Fully protected marine reserves work fast Fish populations double Fish size grows Reproduction triples Species diversity increase by almost one-fourth Protecting Marine Biodiversity: Individuals and Communities Together Integrated Coastal Management Community-based group to prevent further degradation of the ocean More that 100 such groups seek reasonable short term trade offs that can lead to long term ecological and economic benefits How Should We Manage and Sustain Marine Fisheries? Sustaining marine fisheries will require improved monitoring of fish populations, cooperative fisheries management among communities and nations, reduction of fishing subsidies, and careful consumer choices in seafood markets. Estimating and Monitoring Fishery Populations Is the First Step Maximum sustained yield (MSY): maximum number of fish that can be harvested annually without causing a population drop Optimum sustained yield (OSY)-interactions among species Multispecies management – of a number of interacting species Large marine systems: using large complex computer models Precautionary principle because of the uncertainty of all the above methods Some Communities Cooperate to Regulate Fish Harvests Community management of the fisheries – allotment and enforcement systems. Norway’s Lofoten fishery (cod) Co management of the fisheries with the government – sets quotas for various species and divide the quotas among communities. Government Subsidies Can Encourage Overfishing-$30-34 billion around the world 2007: World Trade Organization, U.S. Proposed a ban on fishing subsidies Reduce illegal fishing on the high seas and in coastal waters Close ports and markets to such fishers Check authenticity of ship flags Prosecution of offenders Some Countries Use the Marketplace to Control Overfishing Individual transfer rights (ITRs) Control access to fisheries New Zealand and Iceland Difficult to enforce US 1995 to protect the halibut fishery Problems with the ITR approach transfer ownership of fisheries in publically owned waters to private owners squeeze out small fishing companies Consumer Choices Can Help to Sustain Fisheries and Aquatic Biodiversity 1997: Marine Stewardship Council (MSC), London – 20 nations Certifies that fish caught using sustainable practices Manage global fisheries more sustainably Individuals Organizations Governments SOLUTIONS Managing Fisheries Fishery Regulations Bycatch Set catch limits well below the maximum sustainable yield Use wide-meshed nets to allow escape of smaller fish Improve monitoring and enforcement of regulations Use net escape devices for seabirds and sea turtles Ban throwing edible and marketable fish back into the sea Economic Approaches Sharply reduce or eliminate fishing subsidies Charge fees for harvesting fish and shellfish from publicly owned offshore waters Protect Areas Certify sustainable fisheries Establish no-fishing areas Establish more marine protected areas Rely more on integrated coastal management Consumer Information Label sustainably harvested fish Publicize overfished and threatened species Aquaculture Restrict coastal locations for fish farms Control pollution more strictly Depend more on herbivorous fish species Nonnative Invasions Kill organisms in ship ballast water Filter organisms from ship ballast water Dump ballast water far at sea and replace with deep- sea water Fig. 11-12, p. 265 How Should We Protect and Sustain Wetlands? To maintain the ecological and economic services of wetlands, we must maximize preservation of remaining wetlands and restoration of degraded and destroyed wetlands. Coastal and Inland Wetlands Are Disappearing around the World Highly productive wetlands Provide natural flood and erosion control Maintain high water quality; natural filters Effect of rising sea levels Natural Capital Restoration: Wetland Restoration in Canada Can We Restore the Florida Everglades? “River of Grass”: south Florida, U.S. Since 1948: damaged Drained Diverted Paved over Nutrient pollution from agriculture Invasive plant species 1947: Everglades National Park unsuccessful protection project Can We Restore the Florida Everglades? 1970s: political haggling 1990: Comprehensive Everglades Restoration Plan (CERP) Restore the curving flow of most of the Kissimmee River Remove canals and levees in strategic locations Flood 240 sq. km farmland to create artificial marshes Can We Restore the Florida Everglades? Comprehensive Everglades Restoration Plan (CERP) cont… Create reservoirs and underground water storage areas Build new canals, reservoirs and efficient pumping systems Why isn’t this plan working? The World’s Largest Restoration Project Protect and Sustain Freshwater Lakes, Rivers, and Fisheries Freshwater ecosystems are strongly affected by human activities on adjacent lands, and protecting these ecosystems must include protection of their watersheds. Freshwater Ecosystems Are under Major Threats 40% of the world’s rivers have been dammed or otherwise engineered invasive species, pollution , climate change Repeated Invasions by Alien Species in the Great Lakes Collectively, world’s largest body of freshwater Invaded by at least 162 nonnative species Sea lamprey Zebra mussel Good and bad Quagga mussel Asian carp Zebra Mussels Attached to a Water Current Meter in Lake Michigan, U.S. Managing River Basins Is Complex and Controversial Columbia River: U.S. and Canada Dam system 119 dams , 19 of which are hydroelectric power plants Pros –electricity ; con –salmon affected Snake River: Washington state, U.S. Hydroelectric dams removed Pro – salmon saved ; con – economy affected Natural Capital: Ecological Services of Rivers Protect Freshwater Ecosystems by Protecting Watersheds Freshwater ecosystems protected through Laws Economic incentives Restoration efforts National Wild and Scenic Rivers Act-reestablish protection of rivers Sustainable management of freshwater fishes Priorities for Protecting Biodiversity, Ecosystem Services 2002: Edward O. Wilson Complete the mapping of the world’s terrestrial and aquatic biodiversity Keep old-growth forests intact; cease their logging Identify and preserve hotspots and deteriorating ecosystem services that threaten life Ecological restoration projects Make conservation financially rewarding
