Miller Chapter 9 Review

I.  Chapter 9: Sustaining Biodiversity – Saving Species and Ecosystem Services

  1. 9-1: What Role do Humans Play in the Loss of Species and Ecosystem Services?
  2. Biological Extinction – when a species can no longer be found anywhere on the earth.
  3. The loss of a keystone species or a major reduction in its populations can lead to population declines or extinctions of species with strong connections to such species and to a breakdown in ecosystem services that depend on those connections --- called a trophic cascade
  4. These declines can also result in degradation of habitats and ecosystem series such as chemical cycling and energy flows
  5. Mass Extinction – the extinction of many species in a relatively short period of geologic time
  6. Earth has experienced 5 mass extinctions
  7. After each mass extinction, the earth’s overall biodiversity eventually returned to equal or higher levels, but each recovery required millions of years
  8. The cause of past mass extinctions are poorly understood but probably involved global changes in environmental conditions
  9. Examples: sustained and significant global warming or cooling – large changes in sea level – catastrophes such as multiple large-scale volcanic eruption
  10. Extinction is a natural process
  11. Background Extinction Rate – the rate that existed before modern humans evolved some 200,000 years ago
  12. Scientific evidence indicated that extinction rates have risen in some areas as human populations have spread over most of the globe, destroying and degrading habitats, consuming huge quantities of resources, and creating large and growing ecological footprints
  13. Example: there are 10 million (this makes the problem easier) species on earth. At the background extinction rate of 1 species per million per year, about 10 species would disappear naturally each year. HOWEVER at today’s estimated rate of 100 to 1,000 times the background rate, we are losing between 1,000 and 10,000 species per year or between 2 and 27 species every day on average.
  14. This would amount to a sixth mass extinction cause primarily by human activities with much of it taking place within just one century.
  15. With the loss of such a huge portion of the planet’s biodiversity, we would also likely loss whole ecosystems that depend on the vanishing species, along with the vital ecosystem services the provide, including air and water purification, natural pest control, and pollination
  16. Reasons for a projection of 10,000 times the background extinction rate to happen:
  17. Both the rate of extinction and the resulting threats to ecosystem services are likely to increase sharply during the next 50-100 years because of the harmful environmental impacts of the rapidly growing human population and its growing use of resources per person
  18. The current and projected extinction rates in the world’s biodiversity hotspots – areas that are highly endangered centers of biodiversity – are much higher than the global average
  19. We are eliminating, degrading, fragmenting, and simplifying many biologically diverse environments – including tropical forests, coral reefs, wetlands, and estuaries – that serve as potential sites for the emergence of new species.
  20. We may be limiting the long-term recovery of biodiversity by eliminating these places where new species can evolve – aka creating a speciation crisis
  21. Endangered Species – has so few individual survivors that the species could soon become extinct.
  22. Threatened Species (Vulnerable Species) – still has enough remaining individuals to survive in the short term, but because of declining numbers, it is likely to become endangered in the near future
  23. Types of extinction:
  24. Regionally Extinct – in the areas where they are normally found
  25. Functionally Extinct (extinction of ecological interactions) – when their populations crash to the point where they can no longer play their functional roles in an ecosystem – when a species’ numbers drop to a certain point, its interactions with other species are lost or greatly diminished.
  26. 9-2: Why Should We Care about Sustaining Species and the Ecosystem Services They Provide?
  27. Three major reasons why we should work to prevent our activities from causing or hastening the extinction of other species
  28. World’s species provide vital ecosystem services that help to keep us alive and support our economics
  29. Many species also contribute to economic services on which we depend
  30. Bioprospectors search tropical forest and other ecosystems to find plants and animals that scientist can use to make medicinal drugs
  31. Phytochemicals – certain chemicals such as antioxidants that occur naturally in plants – have the potential to slow aging, reduce pain, and help us to reduce our weight, prevent various cancers, and control diseased such as diabetes
  32. Economic benefit from wildlife tourism, or ecotourism
  33. That analysis of past mass extinctions indicated it will take 5 million to 10 million years for natural speciation to rebuild the biodiversity that is likely to be lost during this century.
  34. Many people believe that wild species have right to exist, regardless of their usefulness to us
  35. 9-3: How do Humans Accelerate Species Extinction and Degradation of Ecosystem Services?
  36. HIPPCO (Habitat Invasive Population Pollution Climate Overexploitation) – the most important direct cause of extinction and threats to ecosystems series
  37. Habitat destruction, degradation, and fragmentation
  38. The greatest threat to wild species
  39. Deforestation in tropical areas - Destruction and degradation of coastal wetlands and coral reefs - Plowing of grasslands - Pollution of streams, lakes, and rivers
  40. Island species – many of them found nowhere else on earth – are especially vulnerable to extinction when their habitats are destroyed, degraded, or fragmented because they have nowhere else to go
  41. Habitat Fragmentation – occurs when a large, intact, area of habitat such as a forest or natural grassland is divided, typically by roads, logging operations, crop fields, or urban developments, into smaller, isolated patches or habitat islands
  42. Can also divide populations of a species into smaller, increasingly isolated groups that are more vulnerable to predators, competitor species, disease, and catastrophic events such as storms and fires
  43. Creates barriers that limit the abilities of some species to disperse and colonize new areas, to locate adequate food supplies, and to find mates
  44. Most National Parks and other nature reserves are habitat islands, many of them surrounded by potentially damaging logging and mining operations, coal-burning power plants, industrial activities, and human settlements
  45. Freshwater lakes are also habitat islands
  46. Invasive (nonnative) species
  47. The deliberate or accidental introduction of harmful species into ecosystems
  48. Many introductions of nonnative species have been beneficial to use – control pest
  49. The problem is when they are introduced in their new habitats, some introduced species do not face the natural predators competitors, parasites, viruses, bacteria, or fungi that had helped to control their numbers in their original habitats.
  50. When this occurs they are now viewed as invasive species
  51. Case Study – Kudzu Vine and Kudzu Bug
  52. A deliberately introduced plant species (Kudzu Vine) – imported from Japan and planted in the southeastern US to help control soil erosion
  53. Kudzu vine is very difficult to kill, even with the use of grazing goats and herbicides, which can also damage other plants and contaminate water supplies
  54. Could spread to the north if the climate gets warmer as scientist project
  55. Almost every part of the kudzu plant is edible
  56. Kudzu Bug (Stinkbug)– the pea-sized bug that spreads evenly more rapidly than the kudzu vine, and it also feeds on soybeans and thus could pose a major threat to soy crops
  57. Some pesticides can kill this bug, but might end of boosting their numbers by promoting genetic resistance to the pesticides
  58. Also evaluating the use of a wasp whose larvae attack kudzu bug embryos
  59. Nonnative invaders arrive from other continents as stowaways on aircraft, in the ballast water of tankers and cargo ships, and as hitchhikers on imported products such as wooden packing crates
  60. Once a harmful nonnative species because established in an ecosystem, its removal is almost impossible – somewhat like trying to collect smoke after it has come out of a chimney – the best way to limit the harmful impacts of nonnative species is to prevent them from being introduced into ecosystems
  61. Funding a massive research program
  62. Greatly increasing ground surveys and satellite observations
  63. Identifying major harmful invader species and establishing international treaties
  64. Requiring cargo ships to discharge their ballast water
  65. Educating the public
  66. Population growth and increasing use of resources
  67. Past and projected human population growth and rising rates of resources use per person have greatly expanded the human ecological footprint – acting together, these two growth factors have caused the extinction of many species
  68. A chemical derived from the pesticide DDT was magnified as it moved up through their food web through processes called bioaccumulation and biomagnification
  69. Climate change – could help to drive a quarter to half of all land animals and plants to extinction by the end of this century
  70. Example: Polar Bear – is threated because of the higher temperatures and melting sea ice in its polar habitat
  71. Scientific measurements reveal that the earth’s atmosphere has been getting warmer since 1975 and that this warming is occurring twice as fast in the Artic as in the rest of the world. Thus artic ice is melting faster than the average annual area of floating sea ice in the Arctic during the summer is decreasing - shortening the polar bears’ hunting season
  72. Some protected species are illegally killed (poached) for their valuable parts of are sold live to collectors
  73. Around the globe, the legal and illegal trade in wild species for sue as pets is a huge and very profitable business
  74. Indigenous people in much of West and Central Africa have sustainably hunted wildlife for bush meat as a source of food
  75. Some areas have skyrocketed as hunters have tried to provide food for rapidly growing populations or to make a living by supplying restaurants in major cities with exotic meats from gorillas and other species
  76. Case Study: A Disturbing Message from the Birds
  77. Approximately 70% of the world’s more than 10,000 known bird species are declining in numbers, and much of this decline is related to human activities (HIPPCO)
  78. Threatened with extinction mostly by habitat loss, degradation, and fragmentation (H in HIPPCO)
  79. The US are endangered, threatened, or in decline, mostly because of habitat loss and degradation invasive species, and climate change
  80. Birds are an indicator species because they live in every climate and biome, respond quickly to environmental changes in their habitats, and are relatively easy to track and count
  81. Perform critically important economic and ecosystem services in ecosystems throughout
  82. Pollution
  83. Can threaten some species with extinction
  84. Climate Change
  85. Overexploitation
  86. 9-4: How Can We Sustain Wild Species and Their Ecosystem Services
  87. Convention on International Trade in Endangered Species (CITES) – 1975 – signed by 178 countries, bans the hunting, capturing, and selling of threatened or endangered species
  88. List 926 species that are in danger of extinction and cannot be commercially traded as live specimens or for their parts or products.
  89. Restricts international trade of roughly 5,000 species of animals and 29,000 species of plants that are at risk of becoming threatened.
  90. Includes elephants, crocodiles, cheetahs, and chimpanzees
  91. But the effects of this treaty are limited because enforcement varies from country to country and convicted violators often pay only small fines
  92. Convention of Biological Diversity (CBD) – ratified or accepted by 193 countries (as of 2012 the US is not included).
  93. It legally commits participating governments to reducing the global rate of biodiversity loss and to equitably sharing the benefits from the use of the world’s genetic resources.
  94. Includes efforts to prevent or control the spread of ecologically harmful invasive species
  95. Focuses on the ecosystems rather than on individual species, and it links biodiversity protection to issues such as the traditional rights of indigenous people
  96. Implementation has been slow – the law contains no severe penalties or other enforcement mechanisms
  97. Case Study – The U.S. Endangered Species Act
  98. Endangered Species Act 1973 (ESA: amended in 1982, 1985, and 1988) – was designed to ID and protect endangered species in the United States and abroad. Is probably the most far-reaching environmental law ever adopted by any nation, which has made it controversial
  99. National Marine Fisheries Service (NMFS) – responsible for ID and listing endangered and threatened ocean species,
  100. U.S. Fish and Wildlife Service (USFWS) – is to ID and list all other endangered and threatened species
  101. The ESA also forbids federal agencies (except the Defense Department) to carry out, fund, or authorize projects that would jeopardize any endangered or threatened species or destroy or modify its critical habitat
  102. Since 1995, there have been numerous efforts to weaken the ESA and to reduce its already meager annual budget
  103. Opponents of the act contend that it puts the rights and welfare of endangered plants and animals above those of people
  104. Biologist insist that is has not been a failure, for three main reasons:
  105. Species are listed only when they face serious dangers of extinction
  106. According to federal data, the conditions of more than half of the listed species are stable or improvement
  107. The 2012 budget for protecting endangered species amounted to an average expenditure of about $.86 per U.S. citizen
  108. The U.S. also needs a new law that emphasizes protecting and sustaining biological diversity and ecosystem services rather than focusing mostly on saving individual species
  109. 1903 – President Theodore Roosevelt established the first U.S. federal wildlife refuge at Pelican Island, Florida
  110. Seed Banks – preserve genetic information and endangered plant species by storing seeds in refrigerated, low-humidity environments
  111. We can take pressure off some endangered or threatened species by raising individuals of these species on farms for commercial sale
  112. Zoos, aquariums, game parks, and animal research centers are being use to preserve some individuals of critically endangered animal species, with the long-term goal of reintroducing the species into protected wild habitats
  113. Two techniques for preserving endangered terrestrial species
  114. Egg pulling – involves collecting wild eggs laid by collecting endangered bird centers and then hatching them in zoos or research centers
  115. Captive Breeding – some or all of the wild individuals