Chapter 18 Conservation of Biodiversity

We are in the midst of a sixth mass extinction.

“Here we are, the most clever species that has ever lived. So how is it that we can destroy the only planet we have?” Jane Goodall

The Sixth Mass Extinction

Extinction: when there are no longer any individuals of a particular species on the Earth.

The Sixth Mass Extinction

• We are currently losing approximately 50,000 species per year.

• That means 0.5% of all species now alive go extinct each year.

Genetic Diversity Scientists want to conserve genetic diversity so that inbreeding will not occur and species can more likely survive environmental change, diseases, increasing beneficial traits

Genetic Diversity• Inbreeding occurs when individuals with similar genotypes, generally relatives, breed with each other.

• Populations with low genetic diversity are likely to suffer inbreeding depression. (this leads to harmful mutations)

American Panther (inbreeding)

Artificial Selection of domestic species can endanger domestic native species if they mingle.Sierra Nevada Bighorn sheep endangered by domestic sheep

Inbreeding Depression• Inbred individuals are more

likely to express harmful mutations.

• Such individuals are ultimately less likely to survive and reproduce.

King Charles II of Spain

Categories of Endangerment

• Extinct: no individuals of the species are known to exist today.

• Threatened: species with a high risk of becoming extinct in the future.

Categories of Endangerment

• Near-threatened: species that are likely to become threatened in the future.

• Least concern: species that are widespread and abundant in numbers.

The Decline of Birds, Mammals, and Amphibians

Amphibians are often most susceptible to humans because they live in water that may be polluted and lay their eggs there. They show mutations very quickly. If there are 1200 species of amphibians, How many amphibians are not a concern? 612 species

Declining biodiversity has many causes.

Declining Biodiversity

Declining global biodiversity can be explained by reference to the five HIPCO Factors…

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 impacts.

Habitat AlterationCan cause species to become endangered

Colorado River

Changing Forests

In our rainforests

Invasive Species• 2nd greatest cause of species

endangerment…1st is habitat loss• Alien species (exotic species):

species that live outside their historical range.

• Invasive species: when alien species spread rapidly across large areas.

• For example, kudzu vine, zebra mussel, silver carp, gypsy moth, starlings in North America.

Kudzu was introduced in the south to control soil erosion and nothing eats it to control its growth.

If we lose bees and pollinators, we lose our crops

Pollution• Threats to biodiversity from pollution can come from toxic contaminants such as pesticides, heavy metals, acids, and oil spills.

• Oil spills may damage entire ecosystems in ways not fully apparent for decades.

Climate Change

• How will climate change affect temperature and precipitation around the world?

• How will this impact biodiversity?

Overharvesting• Overharvesting: individuals of a species are removed at a rate faster than the population can replace them.

• For example, dodo, American bison, passenger pigeon.

Overharvesting• Well into the early 1800s, there were over 50 million American bison on the western plains.

• By the end of that century, fewer than 1,000 remained.

The conservation of biodiversity often focuses on single

species.

California Condor was brought back from extinction by captive breeding, while the Northern spotted owl is

endangered now because of logging

Habitat corridorsAllow for promotion of gene flow between fragmented

populations.

Did you know that plants have the largest number of endangered species? MAUNA KEA

SILVERSWORD    'AHINAHINA is endangered because of habitat loss and decrease in pollinators. It also only blooms every few years.

Lacey Act• Lacey Act: one of the earliest

laws in the United States enacted to control the trade in wildlife.

• First passed in 1900, the act prohibited the transport of illegally harvested game animals, primarily birds and mammals, across state lines.

CITES• CITES: Convention on

International Trade in Endangered Species of Wild Fauna and Flora

• Developed by the United Nations in 1973 to control the international trade of threatened plants and animals.

• Created a “RED” list for organisms that were most likely to be endangered due to trade

CITES

Today, CITIES is an international agreement between 175 countries across the world.

Red List• The International Union for Conservation

of Nature (IUCN) maintains a list of threatened species, known as the Red List.

• Each member country has its own way to monitor and regulate the import and export of animals on the list.

• Sadly, laws are often not enforced due to lack of funding or local support

Rwanda, cannot protect the gorilla due to poor funding. Bush meat is eaten by locals who also fear the gorilla and the body parts (hands, feet, teeth, skull are sold as trinkets and charms

Conservation Legislation Marine Mammal Protection Act: prohibits the

killing of all marine mammals in the United States 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.

Endangered Species Act• Trading in threatened or

endangered species is also illegal.

• Significantly, the act also authorizes the government to purchase habitat that is critical to the species.

Convention on Biological Diversity

• Convention on Biological Diversity: In 1992, world nations came together and created a treaty to protect biodiversity.

• It recognized that biodiversity is an international concern.

Convention on Biological Diversity

The treaty had three objectives:

1. conserve biodiversity

2. sustainably use biodiversity

3. equitably share the benefits that emerge from commercial use of genetic resources (e.g., pharmaceutical drugs)

Debt for Nature Swap

Countries will forgive debt of economically under privileged countries in exchange for preserving habitat

The conservation of biodiversity

sometimes focuses on protecting entire

ecosystems.

Size, Shape, and Connectedness

• When designing and managing protected areas we must consider several points, including:o closeness to another area o how large the area iso the amount of edge habitat the

area contains

Size, Shape, and Connectedness

• Edge habitat: the area where two different communities come together, typically forming an abrupt transition

• For example, where a grassy field meets a forest

• Some species specialize in living at “the edge”

Biosphere Reserves

Protected areas consisting of zones that vary in the amount of permitted

human impact

Biosphere Reserves• Today there are 564 biosphere reserves worldwide.

• Of these, 47 are located in the United States, including Big Bend National Park in Texas.

• Many of these reserves are in developing countries with little money or stable government

Single Large or Several Small (SLOSS)

TV naturalist Chris Packham said pandas might not be worth saving. He believes the tens of millions being spent to save one species could be better spend buying an entire rainforest which would save hundreds of species at risk due to habitat loss.

Review Questions1. What is meant by “we are

in the midst of a sixth mass extinction”?

2. Why is global genetic diversity declining?

3. What is inbreeding depression?

4. What is an endangered species?

Review Questions

1. What is a threatened species?

2. Which of these three groups has the largest number of threatened species: birds, mammals, or amphibians?

3. About how many species are being lost to extinction every year?

Review Questions

1. What does “HIPCO” stand for?

2. Why is habitat loss so serious an issue in a species survival?

3. Is habitat loss confined to the land?

4. Distinguish an alien from a native species.

Review Questions

1. What are invasive species? Give one plant and one animal example.

2. Overharvesting has driven which species to extinction or near-extinction?

3. What is the Red List?

Review Questions

1. What is the Marine Mammal Protection Act of 1972?

2. What is the Endangered Species Act? It is a national (USA) implementation of what international agreement?

Review Questions

1. Why is the “size, shape, and interconnectedness of protected areas” important?

2. In the end, why should humans care about preserving species diversity?