Chapter 10: Biodiversity

Section 1: What is Biodiversity? A World Rich in Biodiversity - “biological diversity” is the number of different species in a given area - Increases as you get closer to the equator ex. tropical rainforest A. Unknown Diversity - Known species are around 1.7 million (mostly insects)

Unknown Diversity

“Known” = been collected and described scientifically. Scientists estimate there are >10 million total species “Known” = been collected and described scientifically. Unknown species may be found in remote wilderness, deep in the ocean, and even cities.

B. Levels of Diversity Species diversity is the number of different species in an area. Ecosystem diversity is the variety of different habitats, communities, and ecological processes within and between ecosystems. Genetic diversity is all the different a genes contained within a population.

2. Benefits of Biodiversity A. Species are Connected to Ecosystems - keystone species play such important roles in ecosystems that if removed the ecosystem may collapse. ex. sea otters in the U.S Pacific coast page 260

Beaver creation of wetland ecosystem increased waterfowl Population increased fish population nesting sites for birds keystone species

B. Species and Population Survival Genetic variation increases the chances that some members of the population may survive environmental pressures or changes. Small and isolated populations are less likely to survive such pressures.

- When a population shrinks, its genetic - When a population shrinks, its genetic diversity decreases as though it is passing through a bottleneck. - Even if such a population is able to increase again, there will be inbreeding within a smaller variety of genes. - The members of the population may then become more likely to inherit genetic diseases.

C. Medical, Industrial, and Agricultural Uses Organisms are used to provide food, clothing, shelter, medicine. ¼ of prescribed drugs come from plants Almost all antibiotics come from fungi chemicals and industrial materials may be developed from all kinds of species. Hybrid crops developed by combining genetic material from more than one species

D. Ethics, Aesthetics, and Recreation - Reasons people give for preserving biodiversity: 1. Ethical reasons- all species have the right to exist whether they have value or not. 2. Aesthetic or personal enjoyment- pets, camping, watching wildlife, etc. 3. Economic reasons- Some regions earn income from ecotourism (tourism in areas that support conservation and sustainable development)

Section 2: Biodiversity at Risk - Mass extinctions: many species going extinct at one time---may be caused by global climate changes?? - Takes millions of years for biodiversity to recover after a mass extinction.

Biodiversity at Risk

Current Extinctions - In the middle of another mass extinction. - Between 1800 and 2100, it is expected that 25% of all species will become extinct. - Humans are the primary reason for these extinctions.

A. Species Prone to Extinction -Species are more prone to become extict if… 1. have small populations in a limited area 2. they migrate 3. need a large or specific habitat 4. they are exploited by humans - Endangered species: numbers so low may become extinct if measures are not taken immediately - Threatened species: numbers are declining and are risk of becoming endangered

2. How Do Humans Cause Extinctions? A. Habitat Destruction and Fragmentation As human populations grow, we use more land to build homes and harvest resources. In the process, we destroy and fragment the habitats of other species. It is estimated that habitat loss causes almost 75 % of the extinctions now occurring.

ex. Due to habitat loss, the Florida Panther is one of the most endangered animals in NA with fewer than 100 left in the remaining population

B. Invasive Exotic Species - exotic species :species that is not native to a particular region. - Even familiar organisms such as cats and rats are considered to be exotic species when they are brought to regions where they never lived before. - Exotic species can threaten native species that have no natural defenses against them.

C. Harvesting, Hunting, and Poaching - Excessive hunting can also lead to extinction as seen in the 1800s and 1900s when 2 billion passenger pigeons were hunted to extinction. - Thousands of rare species worldwide are harvested and sold for use as pets, houseplants, wood, food, or herbal medicine. - Poaching : the illegal harvesting of fish, game, or other species.

D. Pollution - Pesticides, cleaning agents, drugs, and other chemicals used by humans are making their way into food webs around the globe. - we’re not sure of the long-term effects of these chemicals ex. The bald eagle was endangered because of DDT. Although DDT is now illegal to use in the US, it is still manufactured here and used around the world.

Areas of Critical Biodiversity An important feature of areas of the world that contain greater diversity of species is that they have a large portion of endemic species. endemic species: species that is native to a particular place and is found only there. Ecologists often use the #s of endemic plant species as an indicator of overall biodiversity because plants form the basis of ecosystems on land.

Tropical Rain Forests Cover 7% of Earth’s land surface & over half of the world’s species live in these forests Most have never been described--unknown numbers of species are disappearing as tropical forests are cleared for farming/cattle grazing some native people still maintain traditional lifestyles here

Coral Reefs and Coastal Ecosystem Reefs provide food, tourism revenue, coastal protection, and sources of new chemicals, but are poorly studied and not well protected 60% of coral reefs are threatened by human activities, such as pollution, development, and overfishing. Similar threats affect swamps, marshes, shores, and kelp beds.

Islands Islands are colonized by a limited number of species from the mainland. These colonizing species may then evolve into several new species. Thus, islands often hold a very distinct but limited set of species. Many species are endangered because of invasive exotic species (Hawaiian honeycreeper)

Biodiversity Hotspots biodiversity hotspots: most threatened areas of high species diversity (tropical rainforests, coastal areas, and islands) Have high numbers of endemic species & are threatened by humans Most have lost at least 70 percent of their original natural vegetation

Biodiversity Hotspots

Biodiversity in the United States Florida Everglades, the California coastal region, Hawaii, the Midwestern prairies, and the forests of the Pacific Northwest high numbers of species of freshwater fishes, mussels, snails, and crayfish. Diversity is also high among groups of the land plants such as pine trees and sunflowers.

Biodiversity in the United States The California Floristic Province is home to 3,488 native plant species. 2,124 of these are endemic and 565 are threatened or endangered. threats to this area include the use of land for agriculture and housing, dam construction, overuse of water, destructive recreation, and mining—problems of local human population growth.

Section 3: The Future of Biodiversity

Captive-Breeding Programs involve breeding species in captivity, with the hopes of reintroducing them to their natural habitats. Ex.: Californian condor Will these restored populations will ever reproduce in the wild?

Preserving Genetic Material Germ plasm: genetic material (chromosomes and genes) contained within the reproductive, or germ, cells of plants & animals---may be stored as seeds, sperm, eggs, or pure DNA. stored in controlled environments for research or species-recovery efforts.

Zoos, Aquariums, Parks, and Gardens Some zoos house the few remaining members of a species Zoos, wildlife parks, aquariums, and botanical gardens, are living museums of the world’s biodiversity. Often lack resources or knowledge to preserve many threatened species.

More Study Needed saving a few individuals does little to preserve a species as captive species may not reproduce or survive in the wild. small populations are vulnerable to infectious diseases and genetic disorders caused by inbreeding.

Preserving Habitats and Ecosystems most effective way to save species is to protect their habitats. protecting the habitats of endangered and threatened species often means preserving or managing large areas

Conservation Strategies conservationists work to protect entire ecosystems rather than individual species. identify areas of native habitat that can be preserved, restored, and linked into large networks. promote products that have been harvested with sustainable practices More study is needed: How much fragmentation can a particular ecosystem tolerate?

Legal Protection for Species: Endangered Species Act 1st provision: USFWS compiles list of all endangered and threatened species in U.S.—in 2002, 983 species of plants and animals were listed 2nd provision: species protected from human harm 3rd provision: federal gov’t prohibited from carrying out any project that jeopardizes a listed species.

Recovery Plans 4th provision: USFWS must prepare a species recovery plan for each listed species—often involves protecting their habitats Restricting human uses of land is often controversial habitat conservation plan: attempts to protect species across large areas of land through tradeoffs and cooperative agreements

International Cooperation International Union for the Conservation of Nature and Natural Resources (IUCN) facilitates efforts to protect species and habitats. IUCN publishes Red Lists of species in danger of extinction around the world, helps gov’ts manage natural resources, and works with groups like the World Wildlife Fund to sponsor projects such as attempting to stop poaching in Uganda.

International Trade and Poaching CITES (Convention on International Trade in Endangered Species) treaty was the first effective effort to stop the slaughter of African elephants 1989: members of CITES proposed a worldwide ban on all sales, imports, and exports of ivory, hoping to put a stop the problem.

International Trade and Poaching Some people worried that making ivory illegal might increase the rate of poaching instead of decrease it. They argued that illegal ivory, like illegal drugs, might sell for a higher price. But after the ban was enacted, the price of ivory dropped, and elephant poaching declined dramatically.

The Biodiversity Treaty Biodiversity Treaty: international agreement aimed at strengthening national control and preservation of biological resources. Resulted from the United Nations Conference on Environment and Development, also known as the first Earth Summit Goal = preserve biodiversity & ensure the sustainable and fair use of genetic resources in all countries.

Private Conservation Efforts private organizations work to protect species worldwide Ex: World Wildlife Fund encourages the sustainable use of resources and supports wildlife protection; Nature Conservancy helped purchase habitat preserves in 29 countries; Conservation International helps identify biodiversity hotspots; Greenpeace International organizes direct and sometimes confrontational actions.

Greenpeace activists What they’re trying to prevent

Balancing Human Needs Conflict exists between protecting species and human inhabitants endangered species may be source of food or income, may not seem valuable conservationists goal is to make the value of biodiversity understood by more people.