ENVIRONMENTAL SCIENCE CHAPTER 8: Sustaining Biodiversity: The Species Approach

Core Case Study: Polar Bears and Projected Climate Change 20,000 – 25,000 polar bears in Arctic Hunt seals on winter sea ice Global warming is quickly reducing the amount of sea ice and how long it lasts in winter Polar bears have less time to hunt and store fat for summer fasting Projected 30-35% decline by 2050 Potentially extinct from wild by 2100

8-1 What Role Do Humans Play in the Premature Extinction of Species? Concept 8-1 Species are becoming extinct 100 to 1,000 times faster than they were before modern humans arrived on earth, and by the end of this century, the extinction rate is expected be 10,000 times higher than the background rate.

Human Activities and Extinction Background extinction rate Current rate is 100-1000 times background extinction Rate likely to rise to 10,000 times Is a mass extinction coming?

Current Extinction Rate Estimates Are Conservative Species and biodiversity decrease in next 50–100 years Biodiversity hotspot rates higher than global average Degrading, simplifying, and destroying diverse environments

Science Focus: Estimating Extinction Rates (1) Three difficulties Not easy to document – takes a long time Only 2 million species of 8-100 million identified Little is known about the 2 million species

Science Focus: Estimating Extinction Rates (2) Study records of post-human extinctions with previous extinctions from the fossil record DNA copying mistakes How habitat reduction increases extinction Mathematical models Inadequate data and models Normal: 1 million to 10 million years Humans have greatly accelerated this

Ecological Smoke Alarms Endangered species Threatened species The first to go: large, slow, tasty, or have valuable parts Some behaviors make species prone to extinction

Case Study: Extinction of the Passenger Pigeon Audubon, 1813: 3 days for a flock to pass over Extinct by 1900 Good to eat Feathers good for pillows Bones good for fertilizer Easy to kill

8-2 Why Should We Care about Preventing Species Extinction? Concept 8-2 We should prevent the premature extinction of wild species because of the economic and ecological services they provide and because they have a right to exist regardless of their usefulness to us.

Value of Species Instrumental value of biodiversity Food crops Genetic information Medicine Bioprospectors Ecotourism Do not know what we lose when species go extinct

Ethical Obligations Intrinsic (existence) value Stewardship viewpoint

8-3 How Do Humans Accelerate Species Extinction? Concept 8-3 The greatest threats to any species are (in order) loss or degradation of its habitat, harmful invasive species, human population growth, pollution, climate change, and overexploitation.

Causes of Endangerment and Premature Extinction (HIPPCO) Habitat destruction Invasive species Population growth Pollution Climate change Overexploitation

Habitat Loss Deforestation of tropical areas greatest eliminator of species Endemic species Habitat fragmentation

Case Study: Declining Bird Species (1) Decline of ~70% of ~10,000 known species 12% threatened with extinction Birds around humans benefited, but forest species declined Long-distance migrants – greatest decline

Case Study: Declining Bird Species (2) Reasons Habitat loss Habitat fragmentation Climate change Birds are environmental indicators Perform economic and ecological services

Species Introductions Most beneficial – food crops, livestock, pest control 500,000 alien invader species globally 50,000 nonnative species in the U.S. Some definitely not beneficial

Case Study: The Kudzu Vine Kudzu introduced to control erosion Prolific growth Uses Asians use powdered starch in beverages Edible Source of tree-free paper Japanese kudzu farm in Alabama

Disruptions from Accidentally Introduced Species Downside of global trade Downside of traveling Argentina fire ant Burmese python Zebra mussel

Prevention of Nonnative Species (1) Identify characteristics of successful invaders Detect and monitor invasions Inspect imported goods Identify harmful invasive species and ban transfer

Prevention of Nonnative Species (2) Ships discharge ballast waters at sea Introduce natural control organisms of invaders

Human Choices Drive Extinction Human population growth Excessive, wasteful consumption Use of pesticides Climate change

DDT and Bioaccumulation 1950s–1960s fish-eating bird populations drop DDT biologically magnified in food webs Bird’s eggshells thin and fragile Leads to unsuccessful reproduction

Case Study: Where Have All the Honeybees Gone? Honeybees responsible for 80% of pollination of insect-pollinated plants Population down 30% since the 1980s Pesticides Parasitic mites Invasive African honeybees 2008: 36% of honeybee colonies lost Colony collapse disorder New nicotine-based pesticides to blame?

Illegal Killing and Trading of Wildlife Poaching endangers many larger animals, rare plants Over two-thirds die in transit Illegal trade: $1.1 million per hour Wild species depleted by pet trade Exotic plants often illegally gathered

The Value of Wild Rare Species Declining populations increase black market values Rare species valuable in the wild – eco-tourism Some ex-poachers turn to eco-tourism

Rising Demand for Bush Meat Demand increasing with population growth Increased road access Loggers, miners, ranchers add to pressure Local and biological extinctions Spread of HIV and Ebola virus

8-4 How Can We Protect Wild Species from Premature Extinction? Concept 8-4 We can reduce species extinction and help to protect overall biodiversity by establishing and enforcing national environmental laws and international treaties, creating a variety of protected wildlife sanctuaries, and taking precautionary measures to prevent such harm.

International Treaties Convention on International Trade of Endangered Species (CITES) Convention on Biological Diversity (CBD)

U.S. Endangered Species Act (1) National Marine Fisheries Services – ocean species U.S. Fish and Wildlife Service – other species Listings based on biological factors Forbids federal agency projects that jeopardize listed species or habitats

U.S. Endangered Species Act (2) Fines violations on private land Illegal to sell or buy listed species 1,318 species listed USFWS and NMFS supposed to prepare recovery plan – 86% species in 2009

U.S. Endangered Species Act (3) Successful recovery plans include American alligator, grey wolf, and bald eagle Lax enforcement of imports and exports Amended to give private landowners economic incentive to save species

Science Focus: Accomplishments of the Endangered Species Act Biologists defend limited success Species listed only when gravely threatened Takes long time for species to recover >50% endangered species improving Need more funding Develop recovery plans more quickly Core habitat established when listed

Protection of Marine Species ESA and international treaties protect endangered marine reptiles and mammals Challenges to protecting marine species Limited knowledge of species Difficulty in monitoring and enforcing treaties – open oceans

Sea Turtles Threatened Six species critically endangered Loss or degradation of habitat Illegal harvest of eggs Threats from fishing methods Protection measures have helped

Case Study: Protecting Whales (1) Easy to kill International Whaling Commission Sets quotas Often ignored No enforcement powers 1986: Whaling ban, although violated, greatly decreased whale kills

Case Study: Protecting Whales (2) Key countries that violate whaling ban Japan Norway Iceland

Establish Wildlife Refuges National Wildlife Refuge System Wetland refuges: ~75% 40 million American visitors 20% of listed species in refuge system Many refuges in disrepair, and many allow mining, oil drilling, and off-road vehicles

Storing Genetic Information Gene or seed banks Botanical gardens and arboreta Farms – commercial sale of endangered species removes pressure

Zoos and Aquariums for Protection Collect species with long-term goal of returning them into habitat Egg pulling Captive breeding 100–500 captive individuals to avoid extinction 10,000 individuals to maintain capacity for biological evolution

Case Study: Trying to Save the California Condor Last 22 individuals captured Released a few at a time 2009: 167 condors in the wild Threatened by lead poisoning from animal carcasses and gut piles

The Precautionary Principle When substantial preliminary evidence indicates an activity could harm humans or the environment, we should take precautionary measures to prevent or reduce the harm Do even if cause-and-effect relationships are not yet clearly established “Better safe than sorry”

Three Big Ideas from This Chapter - #1 We are greatly increasing the premature extinction of wild species by destroying and degrading their habitats, introducing harmful invasive species, and increasing human population growth, pollution, contributing to projected climate change, and over-exploitation.

Three Big Ideas from This Chapter - #2 We should prevent the premature extinction of wild species because of the economic and ecological services they provide and because they have a right to exist regardless of their usefulness to us.

Three Big Ideas from This Chapter - #3 We can work to prevent the premature extinction of species and to protect overall biodiversity by using laws and treaties, protecting wildlife sanctuaries, and making greater use of the precautionary principle.