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

What Role Do Humans Play in the Premature Extinction of Species? Concept to Learn in Sect. 8-1: Species are becoming extinct 100 to 1,000 times faster than they were at the start of recorded history, 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: the rate of “normal” extinction of various species as a result of changes in local environmental conditions. Current annual rate is 100-1000 times that of background extinction (depending on species) Rate is likely to rise to 10,000 times, bring the annual extinction rate from 0.0001% to 1% Question: Is a mass extinction coming? 1. At 1% extinction rate, ¼ of all plant & animal species could be gone by 2050!

Most think Current Extinction Rate Estimates Are Conservative! Species and biodiversity likely decrease in next 50–100 years 1. We are taking over & using up resources! Biodiversity hotspot rates are much higher than global average extinction rates 1. Ex: tropical rainforests 2. Our efforts need to be focused here! We are continuing to degrade, simplify, and destroy diverse environments (like rainforests, coral reefs, & estuaries) 1. Could lead to an increase in opportunistic species.

Science Focus: Estimating Extinction Rates 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 Therefore, it is difficult/impossible to determine the number of species that are endangered/extinct!

Endangered/threatened species: Our Ecological Smoke Alarms Endangered species: so few survivors, the species could become extinct. Threatened species: still abundant, but declining in numbers. The first to go: those species that are large, slow, tasty, or have valuable parts Some behaviors make species prone to extinction (Ex: passenger pigeon)

Case Study: Extinction of the Passenger Pigeon 1813: There were so many, it took 3 days for a flock to pass over 1. one of the most abundant bird species worldwide! They were extinct by 1900 1. Good to eat 2. Feathers good for pillows 3. Bones good for fertilizer 4. Easy to kill

Why Should We Care about Preventing Species Extinction? Concept to learn in sect. 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.

The “Value” of A Species Instrumental value of biodiversity= it’s “usefulness” to us in providing natural capita Food crops Genetic information Medicine (natural medicines) Bioprospectors (search/find medicines) Ecotourism (much higher value) We don’t fully know what we lose when a species goes extinct

Ethical Obligations: Do we have one? Intrinsic (existence) value: many scientists & philosophers believe each species has an inherent right to exist. Stewardship viewpoint: according to this view, we have an ethical responsibility to protect all species from extinction. Some believe something less than this: 1. who really cares about mosquitos, fleas, cockroaches, etc.

8-3 How Do Humans Accelerate Species Extinction? Concept to Learn in Sect. 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 Destruction Deforestation of tropical areas is the greatest eliminator of species 1. destruction of coral reefs is 2nd. Endemic species: The most vulnerable to extinction (found only in 1 place) Habitat fragmentation: The breaking up of a habitat into pieces, usually caused by human hands 1. Also leads to extinction 2. Hawaii is #1 in species endangered (63%)

Case Study: Declining Bird Species Decline of ~70% of ~10,000 known species 12% threatened (1 in 8) with extinction Birds around humans have benefited, but forest species have declined Long-distance migratory birds have seen the greatest decline

Case Study: Declining Bird Species Reasons: 1. Habitat loss (by human hands) 2. Habitat fragmentation (by human hands) 3. Climate change (greatest new threat) Importance: Birds are environmental indicators! Perform economic and ecological services 1. control populations of rodents & insects 2. spread plants (pollination & seed excretion)

Species Introductions Most species introduced are beneficial: 1. food crops species (wheat, corn, rice) 2. livestock species (cattle, poultry) 3. pest control 500,000 alien invader species globally 50,000 nonnative species in the U.S. Some definitely not beneficial, having no natural predators to control them.

Case Study: The Kudzu Vine Kudzu introduced into US to control soil erosion 1. experienced prolific growth Uses of Kudzu vine: 1. Asians use powdered starch in beverages 2. Edible (all parts!) Source of tree-free paper Can control desire for alcohol Is growing out of control in south US!

Disruptions to Ecosystems from Accidentally Introduced Species Downside of global trade 1. can be found in crates, cargo ships, etc. Downside of traveling 1. seeds can get caught in tires Argentina fire ant- huge problem in US 1. have replaced natural species Burmese python: #’s growing in south US Zebra mussel: cause damage to pipes, grow easily, reduce food for other mussel species.

Prevention of Nonnative Species: Best way to reduce threats! Identify characteristics of successful invaders & vulnerable ecosystems Detect and monitor invasions, & make predictions where they will go next Better inspection of imported goods Identify harmful invasive species and ban their transfer Introduce natural predator species Ships discharge ballast waters at sea

Human Choices Drive Extinction! Human population growth Excessive, wasteful consumption 1. Both have increased human ecological footprint 2. along the coast will affect aquatic environments (coral reefs) Use of pesticides (causing the honeybee to become a threatened species) Climate change (projected to cause extinction of 1/4-1/2 of all plants/animals by 2100.

DDT and Bioaccumulation 1950s–1960s fish-eating bird populations drop DDT is “biologically magnified” in food webs Bird’s eggshells thin and fragile, therefore, reproduction was reduced. A 1972 ban has allowed their numbers to grow.

Case Study: Where Have All the Honeybees Gone? Honeybees responsible for 80% of pollination of insect-pollinated plants Population down 30% since the 1980s, due to: 1. Pesticides 2. Parasitic mites 3. Invasive African honeybees 2008: 36% of honeybee colonies lost due to: 1. Colony collapse disorder 2. Possibly new nicotine-based pesticides to blame.

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

The Value of Wild Rare Species The declining populations increase black market values All rare species are more valuable in the wild (eco-tourism value) Some ex-poachers turn to eco-tourism 1. recognize the greater $ value

Rising Demand for Bush Meat Demand increasing with population growth Increased road access has been given to loggers, miners, ranchers greater opportunity to hunt. Adding to possible extinctions Popularity of bush meat has caused an increase in the spread of HIV and Ebola virus

Sect. 8.4: How Can We Protect Wild Species from Premature Extinction? What to learn in sect. 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 & Laws can help! Convention on International Trade of Endangered Species (CITES) 1. signed by 174 countries 2. bans hunting/capturing/selling of endangered or threatened species. Convention on Biological Diversity (CBD) 1. signed by 190 countries (not US) 2. focuses on ecosystems & ways to prevent invasive species

U.S. Endangered Species Act Identifies/protects endangered species in US & abroad National Marine Fisheries Services: identifies endangered ocean species U.S. Fish and Wildlife Service: identifies other species Listings based on biological factors (not political or economical) Forbids federal agency projects that jeopardize listed species or habitats

U.S. Endangered Species Act Fines violators even on private land Makes it illegal to sell or buy listed species 1,318 species listed USFWS and NMFS are supposed to prepare a recovery plan for all species listed 1. 86% species have plans as of 2009

U.S. Endangered Species Act Successful recovery plans include American alligator, grey wolf, and bald eagle Lacks 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: not quite a failure! 1. Species listed only when gravely threatened 2. Takes long time for species to recover 3. >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 also protect endangered marine reptiles and mammals There are greater challenges to protecting marine species: 1. Limited knowledge of species Difficulty in monitoring and enforcing treaties Open oceans

Sea Turtles Threatened Six species critically endangered, due to: 1. Loss or degradation of habitat 2. Illegal harvest of eggs 3. Threats from fishing methods Protection measures have helped Read about protective measures set in place for sea turtles

Case Study: Protecting Whales So big, they are easy to kill International Whaling Commission: established when their numbers were dwindling. They sets quotas (often ignored) Have no enforcement powers In 1986, established a Whaling ban. 1. Although violated, greatly decreased whale kills (Japan, Iceland & Norway were violators)

Protecting Species Through Establishing Wildlife Refuges National Wildlife Refuge System: Established to protect endangered species Of the refuges created: ~75% are wetland sanctuaries 40 million American visitors (hunting, fishing) Home to 20% of listed endangered species Many refuges in disrepair due to underfunding Many allow mining, oil drilling, and off-road vehicles

Protection of Species thru Storing Genetic Information Gene or seed banks (plants) 1. expensive to maintain Botanical gardens and arboreta 1. contain living plants, but only 3% of those endangered Farms – The raising of endangered species for commercial sale removes pressure

Zoos and Aquariums for Protection of Species: Collect species with long-term goal of returning them into habitat Methods: 1. Egg pulling 2. Captive breeding Need 100–500 captive individuals to avoid extinction 10,000 is the “magic #” of individuals to maintain capacity for species survival

Case Study: Trying to Save the California Condor Last 22 individuals were captured, and bred in captivity. They were released a few at a time 2009: 167 condors in the wild Threatened by lead poisoning (lead pellet shot) from animal carcasses and gut piles 1. left behind by hunters

Protection of Species Thru 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 Should be done even if “cause-and-effect” relationships are not yet clearly established “Better safe than sorry”