Chapter 9: Sustaining Biodiversity

Extinction Fossil record shows evidence of extinction as a natural process:

Background extinction: loss of species at a relatively low rate, often due to changes in local conditions;

Mass extinction: abrupt increases in extinction rates. Mass extinctions believed to result from global climate changes (e.g. meteorite impacts etc.);

Five mass extinctions during past 500 million years, last one ____ million years ago.

•Species are becoming extinct ___________ times faster than they were before modern times.

•By the end of this century, the extinction rate is expected to be 10,000 times the background rate.

•Conservative estimates of extinction = 0.01-1.0% Growth of human population will increase this loss E.O. Wilson estimates that if 1% extinction rate, 1/2 of all species will be gone by 2100

Endangered Species: Species that has so few individuals that the species could soon become _______ over some or most of its natural range.

Threatened Species: Species that is still relatively abundant, but because of ______________ is likely to become endangered in the near future.

Threatened & Endangered Species

Percentage of Various Species Threatened with Premature Extinction

Worldwide about 25% of mammals are at risk of extinction.

The highest percentages at risk are: apes & monkeys (46%) moles & shrews (36%) antelopes & cattle (33%)

Threatened & Endangered Species

• economic & ___________ importance: • scientific & ecological importance: ecological services include nutrient recycling, watershed value, production of oxygen, moderating climate, & detoxifying toxic substances;

• aesthetic & recreational importance:

Why Preserve Wild Species?

Example of medical uses: The blood from 500,000 horseshoe crabs is collected each year. A component of the blood is used to screen injectable medicine for bacteria.

Biomimicry Video: Planes and Butterflies Biomimicry=__________________________________________________________________________________

•http://ww

w.youtube.com/w

atch?v=8shr4ZTI5pY

Why Care About Bats?

80% of bat species are _______ -eaters that control pests that damage crop, mosquitoes populations etc.

(Ecological Service) Certain bats are pollinators of crops

like mangos, and cashews Bats (including local population)

threatened by white-nose fungus

Video: Bats Decline due to White-Nose Fungus

•__________________ , fragmentation & degradation

•_________(nonnative) species •Population and resource use growth

•Pollution •Climate change & pollution •Overexploitation (poaching, overfishing etc.)

HIPPCO

Causes of Extinction & Depletion

•Indian Tiger

•Black Rhino

•African Elephant

•Asian or Indian Elephant

Habitat Loss/Fragmentation Is Most Serious Threat to Biodiversity

•Former Range

•Current Range

Habitat Fragmentation Reduces Genetic Diversity in a Population

Area preserved for wildlife refugee must have adequate population size for genetic diversity

Why is Genetic Diversity Important? _________________________________________

_________________________________________. http://evolution.berkeley.edu/evolibrary/article/_0_0/agriculture_02

Managing populations of waterfowl requires multinational efforts to protect habitats along the flyways.

Case Studies

Introduction of Invasive Species is the 2nd biggest Cause of Biodiversity Loss

Nonnative species may have no natural •_________ •Competitors •Parasites

Examples: Kudzu in Southeastern US

Zebra Mussels in the Great Lakes

Zebra Mussels

Kudzu

Accidentally Introduced Species

Many accidentally introduced aquatic species were carried by the _________________ in tankers or cargo ships.

Deliberately Introduced Species

Biological Control Gone Bad In the 1930’s cane toads were introduced into

Australia to control beetle populations that was devastating cane sugar crop.

Cane toad did not control the beetle population, yet its population grew exponentially in Australia.

Cane Toads are poisonous, and are able to outcompete many native species.

Discuss with your table partner:

Certain classes of animals, including mammals and amphibians, have higher extinction rates. Identify some characteristics that make species more vulnerable to extinction.

• ________________________(e.g., blue whale)

• specialized feeding habits (e.g., panda)

• feed at high trophic level- top of the food chain (e.g., tiger)

• large size (e.g., elephant)

• limited breeding area (e.g., sea turtle)

• limited distribution (e.g., caribou)

Characteristics of Extinction–Prone Species:

• fixed migratory patterns (e.g., whooping crane)

• preys on livestock (e.g., timber wolf)

• small population size (e.g. endemic island species)

• _________________________(e.g. rhinos for horns)

• behaviors that contribute to extinction (e.g., Carolina parakeet- flocks hover over injured bird.)

Characteristics of Extinction–Prone Species Cont.

http://m.flickr.com/photos/wwfint/8043573027/

Why are top consumers more vulnerable to extinction?

Must be supported by a __________________ __________________________.

Much of energy consumed is given off as a heat. Typically, only 10% of energy available for the next

trophic level (step in the food chain).

Why are top consumers more vulnerable to extinction? Cont.

Greater risk of harmful concentrations of toxins that bioaccumulate (get stored in body tissue such as fat).

Due to the energy pyramid, toxins get biomagnified (_____________________) through the food chain.

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pecies often have behaviors that make them vulnerable to extinction

Overfishing: Modern commercial fishing methods enable increasing harvest. Many fish populations decreasing drastically.

Case Studies

• National Marine Fisheries Service (NMFS) charged with protection of marine species;

• U.S. Fish & Wildlife Service charged with listing & protection of all other species;

Protecting Wild Species in the US

Endangered Species Act (ESA) of 1973 requires listing & ________of endangered & threatened species in US.

Government Agencies Involved:

California Condor

Florida panther

International Treaties on Biodiversity

• 1975: Convention on International Trade in Endangered Species (CITES) – Signed by 172 countries – International trade regulation for endangered

species. For example:______________________.

• 1992: Convention on Biological Diversity (BCD) – Focuses on ecosystems – Ratified by 191 countries (not the U.S.)

Example of an issue for consideration by CITES: International trade of rhino horn is banned by CITES, but due to the high price of rhino horn poaching is a persistent problem. The next CITES delegation will consider whether to allow farming of rhino for their horns.

• Pro: _____________________________________ ______________________________________.

• Con: _____________________________________ ______________________________________.

Farming of crocodiles for their skins helped to preserve wild crocodile populations.

Protecting Biodiversity •Ecosystem approach: aims to preserve balanced populations of species in their native habitats. advantage: it focuses on ___________________ to protect ecological integrity & provide habitat for the majority of wild species.

•Species approach: based on identifying & protecting endangered species on a case–by–case basis.

Consensus among conservation biologists is that protecting biodiversity requires both approaches

Preserving Adequate Habitat

US Wilderness Society estimates that a wilderness area should be at least _____________in order to be protected from human activity. About 1.8% of lower US land area is protected as wilderness: In lower US only 4 are larger than 4,000 km2

4,000 km2 box ~63 km wide

Unlike traditional parks & reserves, biosphere reserves recognize _____ ____________ for access to sustainable use of resources in parts of the reserve.

Protecting Biodiversity