Environment in the News
nayo0f033
chapter_15.pptBiological Resources
Chapter 15
Disappearing Frogs
- 168 amphibian species are though to have become extinct in the last 2 decades
- About 1/3 of all amphibian species are threatened
- No single cause of massive die-offs
- Habitat loss, Chemical pollutants, Infectious diseases, UV radiation, Climate change are all suspects
- Chytridiomycosis, rapidly spreading fungal disease has been found in 43 countries and 36 US states, exacerbates harm form other causes
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Species Richness and Biological Diversity
- Learning Objectives:
Describe factors associated with species richness
Define biological diversity and distinguish among species richness, genetic diversity, and ecosystem diversity
Relate several important ecosystem services provided by biological diversity
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Species Richness and Biological Diversity
- Species
- A group of distinct organisms that are capable of interbreeding with one another in the wild but that do not interbreed with organisms outside their group
- How many species?
- 5–100 million species total estimate
- 10,000 new species identified per year
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Species Richness and Biological Diversity
- Species Richness
- The number of different species in a community. Varies form community to community
- Related to the abundance of potential niches
- Inversely related to isolation of community
- Species have difficulty reaching and colonizing isolated places (e.g., islands)
- Locally extinct species are not replaced quickly
- Inversely related to environmental stress
- Usually greater at the edges of adjacent communities than at the center of a community
- Ecotone: a transitional zone where communities meet
- Edge effect: change in species composition that occurs at ecotones
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Species Richness and Biological Diversity
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Species Richness and Biological Diversity
- Why We Need Biodiversity
- The number and variety of Earth’s organisms;
- 3 components:
- Genetic diversity
- Species richness
- Ecosystem diversity
- Humans depend on thousands of species for survival
- Insects for pollination, weed control, pest control
- Bacteria and fungi for food, antibiotics, medicines
- 288,000 out of 330,000 plant species have not been assessed for medicinal, agricultural, or industrial value
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Species Richness and Biological Diversity
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Species Richness and Biological Diversity
- Ecosystem Services and Species Richness
- The activities of all organisms in an ecosystem are interrelated.
- When one species declines, other species linked to it may either decline or increase in number
- Ecosystem Services
- Environmental benefits, such as clean air, clean water, and fertile soil, provided by an ecosystem
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Species Richness and Biological Diversity
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Species Richness and Biological Diversity
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Species Richness and Biological Diversity
- Importance of Genetic Diversity
- Evolution has taken hundreds of millions of years to produce genetic diversity we see today
- Diversity may hold solutions to today’s problems and to problems we have not begun to imagine
- Genetic engineering uses gene diversity
- Variation in wild relatives of crops allows us to introduce variation and resistance to diseases
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Species Richness and Biological Diversity
- Medicinal, Agricultural, and Industrial Importance of Organisms
- Genetic resources of organisms are important to pharmaceutical industry
- AIDS medication AZT is a derivative of a compound extracted from sponges
- 20 best-selling prescription drugs in US are natural products slightly modified or synthetic chemicals derived from organisms
- Agricultural importance is obvious
- We must eat to survive
- Modern Industrial Technology
- Oils, lubricants, perfumes, fragrances, dyes, paper, lumber, waxes, latex,
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Species Richness and Biological Diversity
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Species Richness and Biological Diversity
- Aesthetic, Ethical, Spiritual Value of Organisms
- Recreation, inspiration, spiritual solace
- Our world is a thing of beauty largely because of the diversity of living forms in it
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Global Climate Change
What are two determinants of species richness? Give an example of each
What is biological diversity?
What are ecosystem services? Describe some ecosystem services that a forest provides
Endangered and Extinct Species
- Learning Objectives
Define extinction and distinguish between background extinction and mass extinction
Contrast threatened and endangered species
Describe four human causes of species endangerment and extinction
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Endangered and Extinct Species
- Extinction
- The elimination of a species from Earth
- Natural part of life.
- Background extinction
- Continuous low level of extinction of species
- Mass extinction
- Large number of species disappear during a relatively short period of geologic time
- Although natural process, it can be greatly accelerated by human activities
- Human population growth has disrupted habitats
- Biodiversity is disappearing at an unprecedented rate
- 100 to 1000 times the natural rate of background extinction
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Endangered and Extinct Species
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Endangered and Extinct Species
- Endangered and Threatened Species
- Endangered Species Act legally defines
- Endangered species
- A species is in imminent danger of extinction throughout all or a significant portion of its range
- Threatened species
- A species whose population has declined to the point that it may be at risk of extinction
- Represent a decline in biological diversity because as their numbers decrease their genetic variability is severely diminished
- Lower genetic diversity is heightens the risk of extinction
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Endangered and Extinct Species
- Areas of Declining Biological Diversity
- A concern throughout the US, but mostly
- Hawaii (63% of species are at risk), 2/3 of native forests are gone
- California (29% of species at risk)
- Very serious concern in tropical rain forests
- Being destroyed for human settlements, banana plantations, oil and mineral exploration, etc.
- Home to thousands or millions of species
- Many species are endemic (native to/confined to a particular region), not found anywhere else in the world
- Deforestation affects evolution
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EnviroDiscovery
- Is Your Coffee Bird Friendly?
- Many species of migratory songbirds are in decline
- American’s coffee habits may play a role
- Sun plantations (growing coffee in full sunlight) are becoming more common
- High-input, outproduce shade plantations
- Lots of chemical fertilizers and pesticides
- 94–97 fewer species of birds
- Shade plantations (traditional) are more environmentally friendly
- do not require cutting rain forest
- Support populations of songbirds
- Provides variety of forest products
- Often organic and handpicked
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EnviroDiscovery
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Endangered and Extinct Species
- Earth’s Biodiversity Hotspots
- Relatively small areas of land that contain an exceptional number of endemic species and are at high risk from human activities
- 25 hotspots for plant species contain 29% of world’s endemic species, 27% of endemic mammal species, 38% of endemic reptile species, 53% of endemic amphibian species.
- 20% of the world’s human population lives in hotspots
- 15 hotspots are tropical, 9 are mostly/solely islands
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What a Scientist Sees
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Endangered and Extinct Species
- Human Causes of Species Endangerment
- Loss of habitat is greatest threat
- Pollution
- Spread of invasive species
- Overexploitation
- All this is caused by
- Growth of human populations
- Economic activity
- Uses of technology
- Social, political, cultural factors
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Environmental InSight
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Environmental InSight
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Endangered and Extinct Species
- Habitat Fragmentation
- The breakup of large areas of habitat into small, isolated patches (islands)
- Pollution
- Acid precipitation, stratospheric ozone depletion, climate warming degrade even wilderness habitats that are otherwise undisturbed
- Invasive Species
- Foreign species that spread rapidly in a new area if free of predators, parasites, or resource limitations that may have controlled their population in their native habitat
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Endangered and Extinct Species
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Endangered and Extinct Species
- Invasive Species
- Introduction of non-native species into an ecosystem where it did not evolve often upset the balance among the organisms living in that area and interferes with the ecosystem’s normal functioning
- Maybe introduced by natural means, but in most cases is by human activity, intentionally or non-intentionally
- Ballast water in cargo-carrying ships zebra mussel
- Economic losses and control efforts cost the US about $5 billion/yr
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Endangered and Extinct Species
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Endangered and Extinct Species
- Overexploitation
- Sometimes species become endangered or extinct as a result of deliberate efforts to eradicate or control their numbers
- Ranchers, hunters, governments, farmers
- Unregulated hunting or overhunting
- Illegal hunting/Poaching
- Commercial harvest
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Endangered and Extinct Species
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Global Climate Change
What is background extinction? Mass extinction?
What is the difference between a threatened species and an endangered species?
How do human activities cause species to become endangered or extinct?
Conservation Biology
- Learning Objectives:
Define conservation biology and compare in situ and ex situ conservation
Describe restoration ecology
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Conservation Biology
- The scientific study of how humans affect organisms and of the development of ways to protect biological diversity
- In situ-’in place’
- Includes establishment of parks and reserves, concentrates on preserving biological diversity in nature.
- Ex situ- ‘outside its place’
- Involves preserving biodiversity in human controlled settings: zoos, botanical gardens, seed banks of genetically diverse plant crops
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Conservation Biology
- Protecting Habitats
- Conserving and managing the ecosystem as a whole is the best way to preserve biodiversity
- Human activities adversely affect sustainability, so active management is required
- 3500 national parks, preserves, etc. exist worldwide-not always effective in preservation
- Too small, too isolated
- Little money/expertise to manage them
- Most preserves are in areas of low diversity
- Urgently needed in tropical rain forests, tropical grasslands and savannas, dry forests, river basins
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Conservation Biology
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Conservation Biology
- Wildlife Refuges
- National Wildlife Refuge System-1903
- Most extensive network of lands and waters committed to wildlife preservation in the world
- 545 refuges, at least 1 per state
- Represent all major US ecosystems
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Conservation Biology
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Conservation Biology
- Restoring Damaged or Destroyed Habitats
- Restoration Ecology: the study of the historical condition of a human-damaged ecosystem, with the goal of returning it as closely as possible to its former state
- Reclaim disturbed lands and convert them into areas with high biodiversity, using ecological principles, to return them to a functional and sustainable ecosystem
- Creates habitats, regenerates soil,
- Requires time and expense
- Important component of in situ conservation
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Conservation Biology
- Conserving Species
- Conservation organizations are essential part of the effort to maintain biodiversity.
- Educate policymakers, galvanize public support, provide financial supports for projects
- Work in conjunction with zoos, aquaria, botanical gardens, etc.
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Conservation Biology
- Methods and Goals:
- Reintroduction of endangered species
- Captive-breeding programs
- Seed Banks (gene banks)
- Worldwide, hold millions of seed samples at low temperatures, in small space
- Seeds are safe from habitat destruction, climate change, neglect
- Have been used to reintroduce extinct species
- Some seeds cannot be stored
- Seeds must be grown up and more collected, due to longevity issues, are not continuously exposed to environment evolutionary implications
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Environmental InSight
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Global Climate Change
What is conservation biology and when is in situ conservation used? Ex situ?
What are the goals of restoration ecology?
Conservation Policies and Laws
- Learning Objectives:
Describe the benefits and shortcomings of the US Endangered Species Act?
Relate the purpose of the World Conservation Strategy.
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Conservation Policies and Laws
- Endangered Species Act-1973
- Authorizes FWS to protect endangered and threatened species in the US and abroad
- Currently 1300 species are listed-have legal protection
- Requires FWS to select critical habitats and design detailed recovery plan, including
- Current population size, reasons for it being endangered, actions to help recovery
- ESA updated in 1980, 1985, 1988
- Very controversial legislation, entangled in political wrangling
- Should be strengthened to manage entire ecosystems, rather than individual species
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Conservation Policies and Laws
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Conservation Policies and Laws
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Conservation Policies and Laws
- International Policies and Laws
- World Conservation Strategy - 1980
- Plan to preserve biodiversity and essential ecosystem services on which all life depends for survival
- Earth Summit - 1992
- Each signatory nation (193) must inventory its biodiversity and develop a national conservation strategy
- CITES - 1975
- Bans the hunting, capturing, and selling of endangered and threatened species
- Protects about 30,000 species
- Enforcement varies from country to country-penalties are not severe enough
- Illegal trade continues
- Who Owns world’s biodiversity?
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Conservation Policies and Laws
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Global Climate Change
What are the goals of the Endangered Species Act and why is the ESA considered controversial?
What is the World Conservation Strategy?
Case Study
- Fighting the Asian Carp Invasion
- Two species of Asian carp introduced into southern US as aquaculture species
- ‘escaped’ into natural environment in 1990s during floods
- Fast growing filter feeders, no known predators
- Could disturb food chain of native species in Great Lakes, and ruin commercial fisheries
- Illinois sought emergency closing of canals to prevent entrance of carp into the Great Lakes
- Rejected due to the interests of the shipping industry in the area
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Case Study
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