11

Preserving Biological

Diversity

Chapter Outline

Biodiversity: Signs of Decline

Causes of Extinction and the Decline in Biodiversity

Physical Alteration of Habitat

Commercial Hunting and Harvesting

The Introduction of Foreign Species

Pest and Predator Control

The Collection of Animals and Plants for Human Enjoyment, Research, and Other Purposes

Pollution

Biological Factors That Contribute to Extinction

The Loss of Keystone Species

A Multiplicity of Factors

Why Protect Biodiversity?

Aesthetics and Economics

Food, Pharmaceuticals, Scientific Information, and Products

Protecting Free Services and Saving Money

Ethics - Doing the Right Thing

How to Save Endangered Species and Protect Biodiversity - A Sustainable Approach

Protecting All Species

Stopgap Measures: First Aid for an Ailing Planet

Long-term Preventive Measures

Personal Solutions

Key Terms

natural extinction accelerated extinction endangered species

threatened species sport hunting commercial hunting

subsistence hunting poaching keystone species

ecotourism biodiversity Endangered Species Act

debt-for-nature swap buffer zones wildlife corridor

extractive reserve predator control

Objectives

1. Define the following terms: “natural extinction,” “accelerated extinction,” “endangered species,” and “threatened species.”

2. Discuss the causes of extinction and the decline of biodiversity.

3. List the reasons to protect biodiversity.

4. Discuss the significance of the Endangered Species Act.

5. Summarize the measures used to save endangered species and protect biodiversity.

6. Describe the “debt-for-nature swap” option and discuss where this technique has been used to save biodiversity.

7. Define the following terms: “ecological islands,” “buffer zones,” “wildlife corridor,” and “extractive reserve.”

8. Suggest some actions you can take personally to foster biodiversity.

Lecture Outline

Biodiversity: Signs of Decline - Extinction is a natural process, but our activities have accelerated the rate of species extinction to levels which are neither natural nor desirable.

Causes of Extinction and the Decline in Biodiversity

A. Physical Alteration of Habitat

1. Habitat alteration/destruction is the primary cause of species extinction today.

2. Tropical rainforests comprise the most rapidly disappearing habitat; other threatened, critical habitats include coral reefs, wetlands, estuaries, tall grass prairie, and temperate rainforest.

B. Commercial Hunting and Harvesting - Hunting for profit threatens certain species which are commercially valuable, such as whales, elephants, and large cats.

C. The Introduction of Foreign Species - Foreign species can harm native species through the direct effects of competition and through indirect effects.

D. Pest and Predator Control - Pesticides can harm many non-target species. Some species of predators have been seriously damaged by misguided eradication efforts aimed at protecting livestock.

E. The Collection of Animals and Plants for Human Enjoyment, Research, and Other Purposes - Collecting animals to serve as research specimens or as pets depletes wild populations; trade in wild plants and plant parts has decimated many populations of certain species, especially the cacti and insectivorous plants.

F. Pollution - A wide variety of pollutants threaten wildlife directly and make them more susceptible to disease and environmental stress. Sources include agricultural runoff/drainage, acid rain, global warming, ozone depletion, and various industrial toxins.

G. Biological Factors That Contribute to Extinction - Certain traits make some species especially vulnerable to extinction. These include a high critical population size, specialization, narrow range, large size, and intolerance of human presence.

H. The Loss of Keystone Species - Keystone species, though often inconspicuous or obscure, play a critical role in maintaining ecosystem balance and integrity. Their protection is particularly important.

I. A Multiplicity of Factors - Many of the factors discussed previously may interact to make species loss more probable.

Why Protect Biodiversity? Arguments for protecting endangered species and preserving biodiversity can be made on utilitarian and ethical grounds.

A. Aesthetics - Each species has some aesthetic value; every extinction diminishes the aesthetic quality of human life.

B. Food, Pharmaceuticals, Scientific Information, and Products - A large number of species do or potentially might contribute to human utility; that is, they directly or indirectly benefit us through the provision of health products or scientific information.

C. Protecting Free Services and Saving Money - Natural systems provide billions of dollars of benefits to human societies.

D. Ethics -If, as some believe, every species has a right to exist, then humans have an ethical obligation to respect that right.

How to Save Endangered Species and Protect Biodiversity

A. Protecting All Species - Many ecologically important species could face extinction if efforts are not broadened. Currently, the focus is on saving the most appealing or most visible species.

B. Stopgap Measures: First Aid for an Ailing Planet

1. The Endangered Species Act - The Endangered Species Act is the major legal instrument for species preservation in the U.S.

2. Worldwide, weak laws and inadequate enforcement make species protection more difficult.

3. Captive Breeding Programs - Zoos Lend a Hand

a. Zoo-sponsored captive breeding programs may help save a few critically endangered species.

C. Long-Term Preventive Measures - The following are long-term steps to protect biodiversity:

1. Restructuring Human Systems for Sustainability - Protecting biodiversity will be aided by addressing the root causes of the crisis of unsustainability: our inefficient use of resources, runaway population growth, etc.

2. Setting Aside Biologically Rich Regions

3. Buffer Zones and Wildlife Corridors: Protecting and Connecting Vital Areas

4. Extractive Reserves

5. Improving Wildlife Management

D. Personal Solutions - Saving species and protecting biodiversity require personal action. The following are some suggestions:

1. Use only what you need, and use all resources efficiently.

2. Recycle and buy recycled products.

3. Use renewable resources; support government programs aimed at increasing their use.

4. Help restore ecosystems; support groups that take an active role in these efforts.

5. Limit your family size; support private and government efforts throughout the world to provide family planning services and other means to help slow the growth of the human population.

Suggestions for Presenting the Chapter

· Instructors should review the loss of biodiversity in your state or local area.

· Instructors might involve their classes in restoration projects that focus on habitat improvement to foster biodiversity.

· A review of state sponsored programs to encourage biodiversity often proves to be topical to students. A speaker from your state department of natural resources or a trip to public land in your area often provide good opportunities to explore issues of biodiversity and habitat destruction/preservation.

· Many videos are available on the plight of the tropical rain forest. These can be viewed during regular class time or given as an assignment for viewing outside of class time