Chapter 55

Conservation and Restoration Biology

Overview

• Conservation biology integrates ecology, physiology, molecular biology, genetic and evolutionary biology to conserve diversity at all levels

• Restorative ecology applies ecological principles in an effort to return degraded ecosystems to conditions as similar to their natural state as possible.

Concept 55.5 Human activities threaten Earth’s biodiversity

• Genetic diversity• Species diversity• Ecosystem diversity

All of these levels of biodiversity are affected when an organism becomes extinct.

Figure 55.1 Tropical deforestation in West Kalimantan, Borneo

Why is biodiversity so important?

• Future human generations• Connection to nature• Crucial natural resources• Loss of genes

Figure 55.4 The rosy periwinkle (Catharanthus roseus), a plant that

saves lives

Four major threats to Biodiversity

• Habitat destruction• Introduced species• Overexploitation• Disruption of interaction networks

Figure 55.3 A hundred heartbeats from extinction(a) Philippine eagle

(b) Chinese river dolphin

(c) Javan rhinoceros

Figure 55.6 Two introduced species(a) Brown tree snake, intro- duced to Guam in cargo

(b) Introduced kudzu thriving in South Carolina

Figure 55.7 Overexploitation

Concept 55.2 Conservation focuses on size, genes and habitat

• Biologists focus on conservation at the population and species levels follow 2 main approaches:

Small population approach and declining population approach

Small population approach

• A small population is prone to loops of interbreeding and genetic drift that draw a population down an Extinction vortex

• Key factor is loss of genetic variation necessary to enable an evolutionary response to the environment.

Figure 55.9 Processes culminating in an extinction vortex

Smallpopulation

Inbreeding Geneticdrift

Lower reproduction

Higher mortality

Loss ofgenetic

variabilityReduction inindividual

fitness andpopulationadaptability

Smallerpopulation

Declining population approach

• Focuses on threatened and endangered populations that show a downward trend.

• Emphasizes the environmental factors that caused the population to decline.

Weighing Conflicting Demands

• Determining habitat needs and numbers is often in conflict with demands from science, technology and society.

ie. U.S. Pacific Northwest

Concept 55.3 Landscape conservation aim to sustain biotas

• Historically efforts have been aimed at endangered species. Conservationists are now looking to sustain the ecology of entire ecosystems and communities through landscape ecology.

Figure 55.14 Edges between ecosystems

(a) Natural edges. Grasslands give way to forest ecosystems in Yellowstone National Park.

(b) Edges created by human activity. Pronounced edges (roads) surround clear-cuts in this photograph of a heavily logged rain forest in Malaysia.

Figure 55.15 Amazon rain forest fragments, isolated sections of forest ranging in area from

1 to 100 ha

Figure 55.16 An artificial corridor

Concept 55.4 Restoration ecology

• Many areas altered by human activity are abandoned after usage.

• Ecological succession is slower than the rate of degradation by humans.

• BIOREMEDIATION and BIOLOGICAL AUGMENTATION are key strategies in restorative ecology.

(a) Boundaries of the zoned reserves are indicated by black outlines.

(b) Local schoolchildren marvel at the diversity of life in one of Costa Rica’s reserves.

Nicaragua

CostaRica

Pana

ma

National park land

Buffer zone

PACIFIC OCEAN

CARIBBEAN SEA

Figure 55.19 Zoned reserves in Costa Rica

Figure 55.22 Restoration Ecology Worldwide

Truckee River, Nevada Kissimmee River, Florida

Equator