natural capital degradation: the nile perch
Post on 08-Jan-2018
217 Views
Preview:
DESCRIPTION
TRANSCRIPT
Natural Capital Degradation: The Nile Perch
Core Case Study: A Biological Roller Coaster Ride in Lake Victoria
• Loss of biodiversity and cichlids
• Nile perch: deliberately introduced
• Frequent algal blooms– Nutrient runoff– Spills of untreated sewage– Less algae-eating cichlids
Sustaining Aquatic Biodiversity
Chapter 11
We Have Much to Learn about Aquatic Biodiversity
• Greatest marine biodiversity– Coral reefs– Estuaries – Continental shelf
• Biodiversity is higher– Near the coast than in the open sea – In the bottom region of the ocean than the surface region
Why?
Don’t Forget!
Natural Capital
HIPPCO
Human Activities Are Destroying and Degrading Aquatic Habitats
• Habitat loss and degradation– Marine • Coastal• Ocean floor: effect of trawlers
– Freshwater• Dams• Excessive water withdrawal
Natural Capital Degradation: Area of Ocean Bottom Before and After a Trawler
Invasive Species Are Degrading Aquatic Biodiversity
• Invasive species – Threaten native species– Disrupt and degrade whole ecosystems
• Three examples– Water hyacinth: Lake Victoria (East Africa)– Asian swamp eel: waterways of south Florida – Purple loosestrife: indigenous to Europe
Invasive Water Hyacinths
Science Focus: How Carp Have Muddied Some Waters
• Lake Wingra, Wisconsin (U.S.): eutrophic– Contains invasive species• Purple loosestrife and the common carp
• 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 eutrophication
• Toxic pollutants from industrial and urban areas
biomagnification
Hawaiian Monk Seal
Plastics
Climate Change Is a Growing Threat
• Global warming: sea levels will rise and aquatic biodiversity is threatened– Coral reefs– Swamp some low-lying islands– Drown many highly productive coastal wetlands• New Orleans, Louisiana, and New York City
Warming seas . . . Rising seas . . . Acidic seas
Overfishing and Extinction: Gone Fishing, Fish Gone
• Marine and freshwater fish – Threatened with extinction by human activities
more than any other group of species• Commercial extinction• Collapse of the cod fishery and its domino
effect
Natural Capital Degradation: Collapse of the Cod Fishery Off the Canadian Coast
Watery Wasteland
http://s.ngeo.com/wpf/media-live/photos/000/001/cache/dead-fish-tossed_131_600x450.jpg
•Bycatch
Case Study: Industrial Fish Harvesting Methods
• Trawler fishing
• Purse-seine fishing
• Longlining
• Drift-net fishing
Legal Protection of Some Endangered and Threatened Marine Species
• Why is it hard to protect marine biodiversity? – Human ecological footprint and fishprint are expanding– Much of the damage in the ocean is not visible– The oceans are incorrectly viewed as an inexhaustible
resource– Most of the ocean lies outside the legal jurisdiction of any
country
• Regulatory Approach – CITES, US Marine Mammal Protection Act, US ESA, 1995 International Convention on Biodiverstiy (CBD)
Skip
Solutions
Case Study: Protecting Whales: A Success Story… So Far
• Cetaceans: Toothed whales and baleen whales• 1946: International Whaling Commission (IWC)• 1970: U.S. – Stopped all commercial whaling– Banned all imports of whale products
• 1986: moratorium on commercial whaling– Pros– Cons
Skip
Fig. 11-8b, p. 258
Norwegian Whalers Harpooning a Sperm Whale
Economic Incentives Can Be Used to Sustain Aquatic Biodiversity
• Tourism
• Economic rewards– Reconciliation ecology- See Red Sea Star Restaurant
Ex: Reuven Yosef, Red Sea Star RestaurantCoral reef restoration
Case Study: Holding Out Hope for Marine Turtles
• Carl Safina, Voyage of the Turtle– Studies of the leatherback turtle
• Threats to the leatherbacks– Trawlers– Pollution– Climate change
• Communities protecting the turtles
Skip
Marine Sanctuaries Protect Ecosystems and Species
• Offshore fishing– Exclusive economic zones – High seas
• Law of the Sea TreatyLOST
• Marine Protected Areas (MPAs)
Establishing a Global Network of Marine Reserves: An Ecosystem Approach
• Marine reserves– Closed to• Commercial fishing• Dredging• 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
Other Side
Protecting Marine Biodiversity: Individuals and Communities Together
• Integrated Coastal Management – Community-based group to prevent further degradation of
the oceanfishers, business owners,developers, scientists, citizens, politicians
Estimating and Monitoring Fishery Populations Is the First Step
• Maximum sustained yield (MSY): traditional approach
• Optimum sustained yield (OSY)
• Precautionary principle
Some Communities Cooperate to Regulate Fish Harvests
• Community management of the fisheries
• Lofoten Fishery - Norway
• Comanagement of the fisheries with the government
Skip
Government Subsidies Can Encourage Overfishing
• 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
• Problems with the ITR approach
(% of TAC)
Consumer Choices Can Help to Sustain Fisheries and Aquatic Biodiversity
• 1997: Marine Stewardship Council (MSC), London– Supports sustainable fishing– Certifies sustainably produced seafood
• Manage global fisheries more sustainably– Individuals– Organizations– Governments
Marine Stewardship Council
Solutions: Managing Fisheries
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
BOLSA CHICA
Bolsa Chica Land Trust
Skip
We Can Preserve and Restore Wetlands
• Laws for protection
• Mitigation banking– Ecologists argue this as a last resortSkip
We Need to Set 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
top related