Chapter 18 Conservation of Biodiversity
The 6 th Mass Extinction Extinction- when there are no longer any of the species in the world. We are currently losing approximately 50,000 species per year.
Genetic Diversity Scientists want to conserve genetic diversity so that the species can survive environmental change and inbreeding will not occur. Inbreeding occurs when individuals with similar genotypes, generally relatives, breed with each other.
Categories of Endangerment Extinct- no known species exist today Threatened- species with a high risk of extinction in the future Near-threatened- species that are likely to become threatened in the future Least concern- species are widespread and abundant
Global Extinction Ø Some animals have become prematurely extinct because of human activities. Figure 11-2
Endangered and Threatened Species: Ecological Smoke Alarms Ø Endangered species: so few individual survivors that it could soon become extinct. Ø Threatened species: still abundant in its natural range but is likely to become endangered in the near future. Figure 11-3
Giant panda Black-footed ferret Whooping crane Northern spotted owl Blue whale Mountain gorilla Florida panther California condor Hawksbill sea turtle Black rhinoceros Fig. 11-3, p. 224
Characteristic Low reproductive rate (K-strategist) Specialized niche Narrow distribution Feeds at high trophic level Fixed migratory patterns Rare Commercially valuable Large territories Examples Blue whale, giant panda, rhinoceros Blue whale, giant panda, Everglades kite Many island species, elephant seal, desert pupfish Bengal tiger, bald eagle, grizzly bear Blue whale, whooping crane, sea turtles Many island species, African violet, some orchids Snow leopard, tiger, elephant, rhinoceros, rare plants and birds California condor, grizzly bear, Florida panther Fig. 11-4, p. 225
HIPCO H- Habitat Loss I- Invasive Species P- Pollution C- Climate Change O- Overharvested
Habitat Loss For most species the greatest cause of decline and extinction is habitat loss. Most habitat loss is due to human development
Types of Forests Ø Old-growth forest: uncut or regenerated forest that has not been seriously disturbed for several hundred years. l l 22% of world s forest. Hosts many species with specialized niches. Figure 10-5
Types and Effects of Forest Fires Ø Depending on their intensity, fires can benefit or harm forests. l l Burn away flammable ground material. Release valuable mineral nutrients. Figure 10-13
Solutions: Controversy Over Fire Management Ø To reduce fire damage: l l l Set controlled surface fires. Allow fires to burn on public lands if they don t threaten life and property. Clear small areas around property subject to fire.
Why Should We Care about the Loss of Tropical Forests? Ø About 2,100 of the 3,000 plants identified by the National Cancer Institute as sources of cancer-fighting chemicals come from tropical forests. Figure 10-18
Invasive Species Alien species (exotic species)- species that live outside their historical range. Invasive species- when alien species spread rapidly across large areas. Ex- Kudzu Vine, Zebra Mussel, Silver Carp
INVASIVE SPECIES Ø Many invasive species have been introduced intentionally. Figure 11-11
INVASIVE SPECIES Ø Many invasive species have been introduced unintentionally. Figure 11-11
INVASIVE SPECIES Ø Hydrilla in Arkansas Solution? Pakistani Fly
Characteristics of Successful Invader Species High reproductive rate, short generation time (r-selected species) Pioneer species Long lived High dispersal rate Release growth-inhibiting chemicals into soil Generalists High genetic variability Characteristics of Ecosystems Vulnerable to Invader Species Climate similar to habitat of invader Absence of predators on invading species Early successional systems Low diversity of native species Absence of fire Disturbed by human activities Fig. 11-13, p. 236
What Can You Do? Invasive Species Do not allow wild animals to escape. Do not spread wild plants to other areas. Do not dump the contents of an aquarium into waterways, wetlands, or storm drains. When camping use wood near your campsite instead of bringing firewood from somewhere else. Do not dump unused bait into the water. After dogs visit woods or the water brush them before taking them home. After each use clean your vehicle, mountain bike, surfboard, kayaks, canoes, boats, tent, hiking boots, and other gear before heading for home. Empty all water from canoes, kayaks, dive gear, and other outdoor equipment before heading home. Plant a variety of trees, shrubs, and other plants in your yard to reduce losses from invasive species. Do not buy plants from overseas or swap them with others using the Internet. Fig. 11-14, p. 236
Pollution Threats to biodiversity can come from toxic contaminants such as pesticides, heavy metals, acids, and oil spills.
Pollution Example of biomagnification of DDT in an aquatic food chain. Ø Each year pesticides: l l l l Kill about 1/5 th of the U.S. honeybee colonies. 67 million birds. 6-14 million fish. Threaten 1/5 th of the U.S. s endangered and threatened species. Figure 11-15
DDT in fish-eating birds (ospreys) 25 ppm DDT in large fish (needle fish) 2 ppm DDT in small fish (minnows) 0.5 ppm DDT in zooplankton 0.04 ppm DDT in water 0.000003 ppm, or 3 ppt Fig. 11-15, p. 237
Climate Change The concern is how climate change will affect temperature and precipitation around the world, and how this will impact biodiversity.
Overharvesting When individuals of a species are removed at a rate faster than the population can replace them. Ex- dodo, American bison, passenger pigeon.
OVEREXPLOITATION Ø Some protected species are killed for their valuable parts or are sold live to collectors. Ø Killing predators and pests that bother us or cause economic losses threatens some species with premature extinction. Ø Legal and illegal trade in wildlife species used as pets or for decorative purposes threatens some species with extinction.
Overfishing and Extinction: Gone Fishing, Fish Gone Ø About 75% of the world s commercially valuable marine fish species are over fished or fished near their sustainable limits. l l l l Big fish are becoming scarce. Smaller fish are next. We throw away 30% of the fish we catch. We needlessly kill sea mammals and birds.
Fish farming in cage Trawler fishing Spotter airplane Long line fishing Lines with hooks Trawl flap Trawl bag Trawl lines Sonar Purse-seine fishing Fish school Drift-net fishing Float Buoy Deep sea aquaculture cage Fish caught by gills Fig. 12-A, p. 255
Lacey Act One of the earliest laws in the U.S. to control the trade of wildlife. First passed in 1900, the act prohibited the transport of illegally harvested game animals, primarily birds and mammals, across state lines.
CITES Convention on International Trade in Endangered Species of Wild Fauna and Flora Developed in 1973 to control the international trade of threatened plants and animals. Today, CITIES is an international agreement between 175 countries of the world.
Red List The IUCN keeps a list of threatened species, known as the red list. Each country has its own way to monitor and regulate the import and export of animals on the list.
Conservation Legislation Marine Mammal Protection Act- prohibits the killing of all marine mammals in the U.S. and prohibits the import or export of any marine mammal body parts.
Endangered Species Act Endangered Species Act- first passed in 1973, it authorizes the U.S. Fish and Wildlife Service to determine which species can be listed as threatened or endangered and prohibits the harming of these species. Trading these species is also illegal. The act also authorizes the government to purchase habitat that is critical to the species.
Convention on Biological Diversity In 1992, nations came together and made a treaty to protect biodiversity. The treaty had three objectives: conserve biodiversity, sustainably use biodiversity, and equitably share the benefits that emerge from the commercial use of genetic resources such as pharmaceutical drugs.
Size, Shape and Connectedness When designing and managing protected areas we must consider how close to another area they should be, how large the area is, and the amount of edge habitat the area contains. Edge habitat- the area where two different communities come together, typically forming an abrupt transition. Ex. A grassy field meeting a forest.
Biosphere Reserves Protected areas consisting of zones that vary in the amount of permissible human impact.
NATURE RESERVES Ø Large and medium-sized reserves with buffer zones help protect biodiversity and can be connected by corridors. Ø Costa Rica has consolidated its parks and reserves into 8 megareserves designed to sustain 80% if its biodiversity. Figure 10-10B
Guanacaste Nigaragua Caribbean Sea Arenal Costa Rica Llanuras de Tortuguero La Amistad Bajo Tempisque Panama Cordillera Volcanica Central Pacifico Central Pacific Ocean Peninsula Osa Fig. 10-B, p. 213