Figure 8.5: Marine systems provide a number of important ecological and economic services ( Concept 8-2 ). Questions: Which two ecological services and which two economic services do you think are the most important? Why?
Figure 8.15: Freshwater systems provide many important ecological and economic services ( Concept 8-4 ). Questions: Which two ecological services and which two economic services do you think are the most important? Why?
Figure 11.2: N atural capital degradation. These photos show an area of ocean bottom before (left) and after (right) a trawler net scraped it like a gigantic bulldozer. These ocean-floor communities could take decades or centuries to recover. According to marine scientist Elliot Norse, “Bottom trawling is probably the largest human-caused disturbance to the biosphere.” Trawler fishers disagree and claim that ocean bottom life recovers after trawling. Question: What land activities are comparable to this?
Figure 11.3: One scientist has described this common lionfish as “an almost perfectly designed invasive species.” It reaches sexual maturity rapidly, has large numbers of offspring, and is protected by venomous spines. In the eastern coastal waters of North America, it has few if any predators, except perhaps for people. It is hoped that commercial fishers can find ways to capture lionfish economically and that consumers will choose them from seafood menus.
Figure 11.A: Lake Wingra in Madison, Wisconsin (USA) has become clouded with sediment partly because of the introduction of invasive species such as the common carp. Removal of carp in the experimental area shown here resulted in a dramatic improvement in the clarity of the water and subsequent regrowth of native plant species in shallow water.
Figure 11.4: N atural capital degradation. The Nile perch (right) is a fine food fish that can weigh more than 91 kilograms (200 pounds). However, this deliberately introduced fish has played a key role in a major loss of biodiversity in East Africa’s Lake Victoria (left).
Figure 11.5: Invasive water hyacinths, supported by nutrient runoff, blocked a ferry terminal on the Kenyan shores of Lake Victoria in 1997. By blocking sunlight and consuming oxygen, this invasion has reduced biodiversity in the lake. Scientists reduced the problem at strategic locations by removing the hyacinth and by introducing two weevils (a type of beetle) that feed on the invasive plant.
Figure 11.6: This Hawaiian monk seal was slowly starving to death before a discarded piece of plastic was removed from its snout. Each year, plastic items dumped from ships and garbage barges, and left as litter on beaches threaten the lives of millions of marine mammals, turtles, and seabirds that ingest, become entangled in, or are poisoned by such debris.
Figure 11.7: N atural capital degradation. This graph illustrates the collapse of Canada’s 500-year-old Atlantic cod fishery off the coast of Newfoundland in the northwest Atlantic. Beginning in the late 1950s, fishers used bottom trawlers to capture more of the stock, reflected in the sharp rise in this graph. This resulted in extreme overexploitation of the fishery, which began a steady decline throughout the 1970s, followed by a slight recovery in the 1980s, and then total collapse by 1992, when the fishery was shut down. Despite a total ban on fishing, the cod population has not recovered. The fishery was reopened on a limited basis in 1998 but then closed indefinitely in 2003 and today shows no signs of recovery. (Data from Millennium Ecosystem Assessment)
Figure 11.9: Several major species of sea turtles have roamed the sea for 150 million years. The hawksbill, Kemp’s ridley, and leatherback turtles are critically endangered . Flatbacks live along the coasts of northern Australia and Papua, New Guinea, and are not classified as endangered because they nest in very remote places, but the Australian government classifies them as vulnerable . The loggerhead, green, and olive ridley are classified as endangered . See the photo of an endangered green sea turtle on the title page.
Figure 11.10: This endangered leatherback sea turtle was entangled in a fishing net and could have starved to death had it not been rescued.
Figure 11.11: There are a number of ways to manage fisheries more sustainably and protect marine biodiversity. Questions: Which four of these solutions do you think are the most important? Why?
Figure 11.12: This human-created wetland is located near Orlando, Florida (USA).
Figure 11.13: The world’s largest ecological restoration project is an attempt to undo and redo an engineering project that has been destroying Florida’s Everglades (USA, see photo) and threatening water supplies for south Florida’s rapidly growing population.
Figure 11.14: These zebra mussels are attached to a water current meter in Lake Michigan. This invader entered the Great Lakes through ballast water dumped from a European ship. It has become a major nuisance and a threat to commerce as well as to biodiversity in the Great Lakes.
Figure 11.15: According to U.S. Environmental Protection Agency, two species of Asian carp were close to invading Lake Michigan in 2010. If they become established in Lake Michigan, they are likely to spread rapidly and disrupt the food web that supports the lakes’ native fish populations. Eventually, they could become the dominant fish species in the interconnected Great Lakes .
Bio 105 Chapter 11
MILLER/SPOOLMANLIVING IN THE ENVIRONMENT 17TH Chapter 11 Sustaining Aquatic Biodiversity
Case Study: Protecting Whales: A Success Story… So Far (1)• Cetaceans: Toothed whales and baleen whales• 8 of 11 major species hunted to commercial extinction by 1975• 1946: International Whaling Commission (IWC) • Quotas based on insufficient data • Quotas often ignored
Case Study: Protecting Whales: A Success Story… So Far (2)• 1970: U.S. • Stopped all commercial whaling • Banned all imports of whale products• 1986: IWC moratorium on commercial whaling • 42,480 whales killed in 1970 • 1500 killed in 2009 • Norway, Japan, and Iceland ignore moratorium
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
Natural Capital: Marine Ecosystems Fig. 8-5, p. 172
Natural Capital: Freshwater Systems Fig. 8-15, p. 181
Human Activities Are Destroying and Degrading Aquatic Habitats• Marine • Coral reefs • Mangrove forests • Seagrass beds • Sea-level rise from global warming will harm coral reefs and low-lying islands with mangrove forests • Ocean floor: effect of trawlers• Freshwater • Dams • Excessive water withdrawal
Natural Capital Degradation: Area of Ocean Bottom Before and After a Trawler Fig. 11-2, p. 252
Invasive Species Are Degrading Aquatic Biodiversity• Invasive species • Threaten native species • Disrupt and degrade whole ecosystems• Two examples • Asian swamp eel: waterways of south Florida • Lionfish in the Atlantic
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
Lake Wingra in Madison, Wisconsin Fig. 11-A, p. 255
Case Study: Invaders Have Ravaged Lake Victoria• Loss of biodiversity and cichlids• Nile perch: deliberately introduced• Frequent algal blooms • Nutrient runoff • Spills of untreated sewage • Less algae-eating cichlids• Water hyacinths
Natural Capital Degradation:The Nile Perch In Lake Victoria Fig. 11-4a, p. 254
Water Hyacinths in Lake Victoria Fig. 11-5, p. 255
Population Growth and Pollution Can Reduce Aquatic Biodiversity• More noise and crowding from humans• Nitrates and phosphates, mainly from fertilizers, enter water • Leads to eutrophication• Toxic pollutants from industrial and urban areas• 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
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: no longer economically feasible to harvest a species• Collapse of the Atlantic cod fishery and its domino effect• Fewer larger fish• More problems with invasive species
Natural Capital Degradation: Collapse of the500 year old Cod Fishery Off the Canadian Coast Started using bottom trawlers in late 1950s. Fig. 11-7, p. 257
Case Study: Industrial Fish Harvesting Methods• Trawler fishing• Purse-seine fishing• Longlining• Drift-net fishing• Bycatch problem
Legal Protection of Some Endangered and Threatened Marine Species • Why is it hard to protect marine biodiversity? 1. Human ecological footprint and fishprint are expanding 2. Much of the damage in the ocean is not visible 3. The oceans are incorrectly viewed as an inexhaustible resource 4. Most of the ocean lies outside the legal jurisdiction of any country
Case Study: Holding Out Hope for Marine Turtles• Threats to the leatherback turtle • Trawlers and drowning in fishing nets • Hunting • Eggs used as food • Pollution • Climate change• Fishing boats using turtle excluder devices• Communities protecting the turtles
An Endangered Leatherback Turtle is Entangled in a Fishing Net Fig. 11-10, p. 262
Establishing a Global Network of Marine Reserves: An Ecosystem Approach (1)• 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
Establishing a Global Network of Marine Reserves: An Ecosystem Approach (2)• Fully protected marine reserves work fast • Fish populations double • Fish size grows • Reproduction triples • Species diversity increase by almost one-fourth• Cover less than 1% of world’s oceans • Marine scientists want 30-50%
Individuals Matter: Creating an Artificial Coral Reef in Israel• Reuven Yosef, Red Sea Star Restaurant • Coral reef restoration • Reconciliation ecology-humans should increase biodiversity in human-dominated landscapes • Treatment of broken coral with antibiotics
Protecting Marine Biodiversity: Individuals and Communities Together • Oceans 30% more acidic from increased carbon dioxide in atmosphere and increased temperature • Integrated Coastal Management • Community-based group to prevent further degradation of the ocean
Estimating and Monitoring Fishery Populations Is the First Step• Maximum sustained yield (MSY): traditional approach• Optimum sustained yield (OSY)• Multispecies management• Large marine systems: using large complex computer models• Precautionary principle
Some Communities Cooperate to Regulate Fish Harvests• Community management of the fisheries• Co-management of the fisheries with the government • Government sets quotas for species and divides the quotas among communities • Limits fishing seasons • Regulates fishing gear
Government Subsidies Can Encourage Overfishing• Governments spend 30-34 billion dollars per year subsidizing fishing• Often leads to overfishing• Discourages long-term sustainability of fish populations
Consumer Choices Can Help to Sustain Fisheries and Aquatic Biodiversity • Need labels to inform consumers how and where fish was caught • 1999: Marine Stewardship Council (MSC) • Certifies sustainably produced seafood • Proper use of sustainable aquaculture • Plant eating fish best -- Tilapia
Solutions: Managing Fisheries Fig. 11-11, p. 267
We Can Preserve and Restore Wetlands• Laws for protection • Zoning laws steer development away from wetlands • In U.S., need federal permit to fill wetlands greater than 3 acres• Mitigation banking • Can destroy wetland if create one of equal area • Ecologists argue this as a last resort
Human-Created Wetland in Florida Fig. 11-12, p. 268
Case Study: Can We Restore the Florida Everglades? (1)• “River of Grass”: south Florida, U.S.• Damage in the 20th century • Drained • Diverted • Paved over • Nutrient pollution from agriculture • Invasive plant species• 1947: Everglades National Park unsuccessful protection project
Case Study: Can We Restore the Florida Everglades? (2)• 1990: Comprehensive Everglades Restoration Plan (CERP) 1. Restore curving flow of ½ of Kissimmee River 2. Remove canals and levees in strategic locations 3. Flood farmland to create artificial marshes 4. Create 18 reservoirs to create water supply for lower Everglades and humans 5. Recapture Everglades water flowing to sea and return it to Everglades• Already weakened by Florida legislature
The World’s Largest Restoration Project Fig. 11-13, p. 269
Case Study: Can the Great Lakes Survive Repeated Invasions by Alien Species?• Collectively, world’s largest body of freshwater• Invaded by at least 162 nonnative species • Sea lamprey • Zebra mussel • Quagga mussel • Asian carp
Zebra Mussels Attached to a Water Current Meter in Lake Michigan Fig. 11-14, p. 271
Asian Carp from Lake Michigan Fig. 11-15, p. 271
Using an Ecosystem Approach to Sustaining Aquatic Biodiversity• Edward O. Wilson • Complete the mapping of the world’s aquatic biodiversity • Identify and preserve aquatic diversity hotspots • Create large and fully protected marine reserves • Protect and restore the world’s lakes and rivers • Ecological restoration projects worldwide • Make conservation financially rewarding
Three Big Ideas1. The world’s aquatic systems provide important ecological and economic services, and scientific investigation of these poorly understood ecosystems could lead to immense ecological and economic benefits.2. Aquatic ecosystems and fisheries are being severely degraded by human activities that lead to aquatic habitat disruption and loss of biodiversity.3. We can sustain aquatic biodiversity by establishing protected sanctuaries, managing coastal development, reducing water pollution, and preventing overfishing.