Sustaining Aquatic Biodiversity

Sustaining Aquatic Biodiversity
Chapter 12 Sustaining Aquatic Biodiversity

Chapter Overview Questions
What do we know about aquatic biodiversity, and what is its economic and ecological importance? How are human activities affecting aquatic biodiversity? How can we protect and sustain marine biodiversity? How can we manage and sustain the world’s marine fisheries?

Chapter Overview Questions (cont’d)
How can we protect, sustain, and restore wetlands? How can we protect, sustain, and restore lakes, rivers, and freshwater fisheries?

Core Case Study: A Biological Roller Coaster Ride in Lake Victoria
Lake Victoria: the size of Lake Superior, with several hundred unique species of fish in the cichlid family. Lake Victoria has lost their endemic fish species to large introduced predatory fish.

Lake Victoria Problems
Nile Perch and Water Hyacinth - Introduced Species

Core Case Study: A Biological Roller Coaster Ride in Lake Victoria
Reasons for Lake Victoria’s loss of biodiversity: Introduction of Nile perch - huge fish that eats the native cichlids. Lake experienced algal blooms from nutrient runoff, sewage spills, and loss of algae-eating cichlids.. Invasion of water hyacinth has blocked sunlight and deprived oxygen. Nile perch is now in decline because it has eaten its own food supply.

11-1 What Are the Major Threats to Aquatic Biodiversity?
Concept 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

AQUATIC BIODIVERSITY We know fairly little about the biodiversity of the world’s marine and freshwater systems. The greatest marine biodiversity occurs in coral reefs, estuaries and the deep ocean floor. Biodiversity is higher near the coast and surface because of habitat and food source variety. The world’s marine and freshwater systems provide important ecological and economic services.

Human Activities Are Destroying and Degrading Aquatic Habitats
Habitat loss and degradation Marine Coastal Ocean floor: effect of trawlers Freshwater Dams Excessive water withdrawal

HUMAN IMPACTS ON AQUATIC BIODIVERSITY
Human activities have destroyed, disrupted or degraded a large proportion of the world’s coastal, marine and freshwater ecosystems. Approximately 20% of the world's coral reefs have been destroyed. During the past 100 years, sea levels have risen centimeters. We have destroyed more than 1/3 of the world’s mangrove forests for shipping lanes.

Area of ocean before and after a trawler net, acting like a giant plow, scraped it. Figure 12-2

Invasive Species Are Degrading Aquatic Biodiversity
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 Treating with natural predators—a weevil species and a leaf-eating beetle—Will it work?

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 14

Science Focus: How Carp Have Muddied Some Waters
Lake Wingra, completely green with algae, except where carp have been excluded.

Harmful invasive species are an increasing threat to marine and freshwater biodiversity. Bioinvaders are blamed for about 2/3 of fish extinctions in the U.S. between Almost half of the world’s people live on or near a coastal zone and 80% of ocean water pollution comes from land-based human activities.

Population Growth and Pollution Can Reduce Aquatic Biodiversity
Nitrates and phosphates mainly from fertilizers enter water Leads to eutrophication: Nutrient-enhanced algae growth, which makes water less clear and can cause algae blooms - these overgrowths of algae end up reducing dissolved oxygen levels, since the bacteria that decompose the algae use up the oxygen in the water Toxic pollutants from industrial and urban areas

Population Growth and Pollution
Each year plastic items dumped from ships and left as litter on beaches threaten marine life. Figure 12-3

The Great Pacific Garbage Patch
Floating trash gets carried by oceanic currents (“gyres” when they make a circle) Trash gets concentrated in certain locations (one east of Japan, another 1000 miles west of the US) The “Trash Soup” covers an area twice the size of Texas, requiring several days to sail through it! Other garbage patches exist on the other oceans The big issue is that plastic is not biodegradable – it will break down into tiny pieces (called “nurdles”), but living things can not use them. They just accumulate inside organisms, preventing digestion

The Great Pacific Garbage Patch

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

Science Focus: 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

Science Focus: Protecting and Restoring Mangroves
$1.6 billion per year in ecosystem services (nursery grounds for fish, protect coasts from erosion....)

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: species fished so intensely that their populations drop to the point where they are no longer profitable to catch Collapse of the cod fishery and its domino effect Bycatch: capture of unwanted fish and invertebrates, which are usually just thrown overboard (most of the bycatch does not survive the experience)

Overfishing and Extinction: Gone Fishing, Fish Gone
About 75% of the world’s commercially valuable marine fish species are over fished or fished near their sustainable limits. Big fish are becoming scarce - so their price goes up, and we try harder to catch them, which makes their populations drop, so they become more expensive - a positive feedback loop! Example: one bluefin tuna may be worth $100,000 in Japan! Smaller fish are next. We throw away 30% of the fish we catch. We needlessly kill sea mammals and birds.

Case Study: Industrial Fish Harvesting Methods
Trawler fishing: Drag weighted nets across the bottom, scraping up everything in their path Purse-seine fishing: Wrap a net around a school of fish at the surface, then close the bottom and draw it in Longlining: Fishing line up to many miles in length, with as many as 2500 baited hooks spread out along it Drift-net fishing: Floating nets that may be several miles in length. If they break free of the boat, they are called “ghost nets” and continue to kill fish, birds, turtles, and whales as they drift around the sea.

Deep sea aquaculture cage Fish caught by gills
Trawler fishing Fish farming in cage Spotter airplane Sonar Purse-seine fishing Trawl flap Trawl lines Fish school Trawl bag Drift-net fishing Long line fishing Float Buoy Figure 12.A Natural capital degradation: major commercial fishing methods used to harvest various marine species. These methods have become so effective that many fish species have become commercially extinct. Lines with hooks Deep sea aquaculture cage Fish caught by gills Fig. 12-A, p. 255

11-2 How Can We Protect and Sustain Marine Biodiversity?
Concept 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 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

Why is it Difficult to Protect Aquatic Biodiversity?
Rapid increasing human impacts, the invisibility of problems, citizen unawareness, and lack of legal jurisdiction hinder protection of aquatic biodiversity. Human ecological footprint is expanding. Much of the damage to oceans is not visible to most people. Many people incorrectly view the oceans as an inexhaustible resource.

PROTECTING AND SUSTAINING MARINE BIODIVERSITY
Laws, international treaties, and education can help reduce the premature extinction of marine species. Since 1989 the U.S. government has required offshore shrimp trawlers to use turtle exclusion devices. Sea turtle tourism brings in almost three times as much money as the sale of turtle products.

Six of the world’s seven major turtle species are threatened or endangered because o human activities. Figure 12-4

Case Study: Holding Out Hope for Marine Turtles
Carl Safina, Voyage of the Turtle Studies of the leatherback turtle Threats to the leatherbacks Trawlers - shrimp boats in the US must use TEDs: Turtle Excluder Devices Pollution and litter - plastic bags look like jellyfish Climate change Beachfront development on turtle egg-laying beaches - even their lights can be a problem, since the hatchlings may be attracted to them, as if they were the moon reflecting on the water Communities protecting the turtles

Case Study: The Florida Manatee and Water Hyacinths
Manatee can eat unwanted Water Hyacinths. Endangered due to: Habitat loss. Entanglement from fishing lines and nets. Hit by speed boats. Stress from cold. Low reproductive rate Figure 12-B

Case Study: Commercial Whaling
After many of the world’s whale species were overharvested, commercial whaling was banned in 1960, but the ban may be overturned. Figure 12-6

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

Case Study: Commercial Whaling
Despite ban, Japan, Norway, and Iceland kill about 1,300 whales of certain species for scientific purposes. Although meat is still sold commercially. Figure 12-5

How Would You Vote? Should carefully controlled commercial whaling be resumed for species with populations of 1 million or more? No. The hunting of whales is no longer necessary and simply encourages disrespect for these intelligent giants. Yes. Some whale species have recovered and products from them are valuable resources for humans.

Fully protected marine reserves make up less than 0.3% of the world’s ocean area. Studies show that fish populations double, size grows by almost a third, reproduction triples and species diversity increases by almost one fourth. Some communities work together to develop integrated plans for managing their coastal areas.

Economic Incentives Can Be Used to Sustain Aquatic Biodiversity
Tourism Economic rewards Reconciliation ecology

Individuals Matter: Creating an Artificial Coral Reef in Israel
Reuven Yosef, Red Sea Star Restaurant Coral reef restoration Reconciliation ecology Treatment of broken coral with antibiotics

Marine Sanctuaries Protect Ecosystems and Species
Offshore fishing Exclusive economic zones: Countries claim rights to oceanic resources within 200 nautical miles of their coastlines High seas: Free-for-all; Tragedy of the Commons Law of the Sea Treaty Marine Protected Areas (MPAs): like aquatic wildlife refuges, with varying limits on the ways that oceanic resources can be used

Establishing a Global Network of Marine Reserves: An Ecosystem Approach (1)
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 As fish populations within the protected area increase, they expand into non-protected areas, which benefits the local fishing economy more than if fishing was allowed in the protected area

Revamping Ocean Policy
Two recent studies called for an overhaul of U.S. ocean policy and management. Develop unified national policy. Double federal budget for ocean research. Centralize the National Oceans Agency. Set up network of marine reserves. Reorient fisheries management towards ecosystem function. Increase public awareness.

Protecting Marine Biodiversity: Individuals and Communities Together
Integrated Coastal Management Community-based group to prevent further degradation of the ocean

11-3 How Should We Manage and Sustain Marine Fisheries?
Concept 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 (1)
Maximum sustained yield (MSY): traditional approach - but definition of “sustainable” has often favored the fishing industry and resulted in declining fish stocks and fewer fish caught Optimum sustained yield (OSY): modified approach that tries to include impacts on other species (bycatch) and leaves more room for error in estimating populations Multispecies management: attempts to manage marine resources as communities of many species instead of focusing on single species

Estimating and Monitoring Fishery Populations Is the First Step (2)
Large marine systems: using large complex computer models to try to include as many influences on fish populations as possible – technically difficult and politically challenging to implement Precautionary principle!! If you don’t know what will happen, maybe it’s best to avoid it! Or at least to proceed slowly until you do understand the system....

Some Communities Cooperate to Regulate Fish Harvests
Community management of the fisheries Comanagement of the fisheries with the government

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

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

Consumer choices influence fishing practices
Seafood Watch - consumer guide to ordering sustainable & healthy fish Consumer outrage over tuna boats killing dolphins changed fishing boat practices to reduce bycatch

MANAGING AND SUSTAINING MARINE FISHERIES
There are a number of ways to manage marine fisheries more sustainably and protect marine biodiversity. Some fishing communities regulate fish harvests on their own and others work with the government to regulate them. Modern fisheries have weakened the ability of many coastal communities to regulate their own fisheries.

Solutions Managing Fisheries Fishery Regulations
Set catch limits well below the maximum sustainable yield Improve monitoring and enforcement of regulations Bycatch Use wide-meshed nets to allow escape of smaller fish Use net escape devices for sea birds 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 Certify sustainable fisheries Aquaculture Restrict coastal locations for fish farms Control pollution more strictly Depend more on herbivorous fish species Protected Areas Establish no-fishing areas Establish more marine protected areas Rely more on integrated coastal management Figure 12.7 Solutions: ways to manage fisheries more sustainably and protect marine biodiversity. QUESTION: Which four of these solutions do you think are the most important? 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 Consumer Information Label sustainably harvested fish Publicize overfished and threatened species Fig. 12-7, p. 261

11-4 How Should We Protect and Sustain Wetlands?
Concept 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 - high primary productivity Important habitat for fish, birds, and other wildlife Provide natural flood and erosion control Maintain high water quality; natural filters that remove sediments and pollutants Effect of rising sea levels may be reduced by maintaining wetlands Yet often thought of as a “waste of land” - so often drained or filled for development

PROTECTING, SUSTAINING, AND RESTORING WETLANDS
Requiring government permits for filling or destroying U.S. wetlands has slowed their loss, but attempts to weaken this protection continue. Figure 12-8

Wetlands Mitigation Projects that destroy wetlands must “mitigate” their damage by enhancing, restoring, or creating wetlands elsewhere May only apply to government projects Example in Reno: extension of freeway from Neil Road to Mt. Rose Highway 15 years ago required filling in wetlands in Double Diamond area (the “Truckee Meadows” were really the “Truckee Marshes”) - Highway department built ponds, canals, and dams to expand wetlands at south end of Washoe Lake as a mitigation project

Mitigation Wetlands in Washoe Valley -
Open to the public (except during nesting season)

We Can Preserve and Restore Wetlands
Laws for protection Mitigation banking Ecologists argue this as a last resort, since it is harder and more expensive to rebuild an ecosystem than it is to retain it in the first pace

Individuals Matter: Restoring a Wetland
Jim Callender: 1982 Scientific knowledge + hard work = a restored wetland in California, U.S. Marsh used again by migratory fowl

Solutions Protecting Wetlands Legally protect existing wetlands
Steer development away from existing wetlands Use mitigation banking only as a last resort Require creation and evaluation of a new wetland before destroying an existing wetland Restore degraded wetlands Try to prevent and control invasions by nonnative species Figure 12.9 Solutions: ways to help sustain the world’s wetlands. QUESTION: Which two of these solutions do you think are the most important? Fig. 12-9, p. 264

Case Study: Restoring the Florida Everglades
The world’s largest ecological restoration project involves trying to undo some of the damage inflicted on the Everglades by human activities. 90% of park’s wading birds have vanished. Other vertebrate populations down 75-95%. Large volumes of water that once flowed through the park have been diverted for crops and cities. Runoff has caused noxious algal blooms.

Restoring the Florida Everglades
The project has been attempting to restore the Everglades and Florida water supplies. Figure 12-10

Case Study: Can We Restore the Florida Everglades? (1)
“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

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 Goal?

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?

11-5 How Can Protect and Sustain Freshwater Lakes, Rivers, and Fisheries?
Concept Freshwater ecosystems are strongly affected by human activities on adjacent lands, and protecting these ecosystems must include protection of their watersheds.

PROTECTING, SUSTAINING, AND RESTORING LAKES AND RIVERS
Lakes are difficult to manage and are vulnerable to planned or unplanned introductions of nonnative species. For decades, invasions by nonnative species have caused major ecological and economic damage to North America’s Great lakes. Number one cause of fish extinctions in US

Collectively, world’s largest body of freshwater
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 Good and bad Quagga mussel Asian carp

Managing River Basins Is Complex and Controversial
Columbia River: U.S. and Canada Dam system Pros and cons Snake River: Washington state Hydroelectric dams Salmon in Nevada? Yes, via the Owyhee River, a tributary of the Snake!

Dams can provide many human benefits but can also disrupt some of the ecological services that rivers provide. 119 dams on Columbia River have sharply reduced (94% drop) populations of wild salmon. U.S. government has spent $3 billion in unsuccessful efforts to save the salmon. Removing hydroelectric dams will restore native spawning grounds. Many dams are obsolete, and electricity generation would not be affected if they were removed.

How Would You Vote? Should federal efforts to rebuild wild salmon populations in the Columbia River Basin be abandoned? a. No. Restoring salmon populations is critical for the environmental health of the river and surrounding forests. b. Yes. The restoration program would create unnecessary and severe economic hardships for local residents.

We Can Protect Freshwater Ecosystems by Protecting Watersheds
Freshwater ecosystems protected through Laws Economic incentives Restoration efforts Wild rivers and scenic rivers Sustainable management of freshwater fishes

We can help sustain freshwater fisheries by building and protecting populations of desirable species, preventing over-fishing, and decreasing populations of less desirable species. A federal law helps protect a tiny fraction of U.S. wild and scenic rivers from dams and other forms of development. National Wild and Scenic Rivers Act (1968).

Ecological Services of Rivers
Natural Capital Ecological Services of Rivers Deliver nutrients to sea to help sustain coastal fisheries Deposit silt that maintains deltas Purify water Renew and renourish wetlands Provide habitats for wildlife Figure 12.11 Natural capital: important ecological services provided by rivers. Currently, the services are given little or no monetary value when the costs and benefits of dam and reservoir projects are assessed. According to environmental economists, attaching even crudely estimated monetary values to these ecosystem services would help sustain them. QUESTIONS: Which two of these services do you think are the most important? Which two of these services do you think we are most likely to decline? Fig , p. 267

11-6 What Are the Priorities for Sustained Biodiversity, Ecosystem Services?
Concept Sustaining the world’s biodiversity and ecosystem services will require mapping terrestrial and aquatic biodiversity, maximizing protection of undeveloped terrestrial and aquatic areas, and carrying out ecological restoration projects worldwide.

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 Biophilia: people love nature!

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