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Chapter 55. Conservation and Restoration Biology. Overview. Conservation biology integrates ecology, physiology, molecular biology, genetic and evolutionary biology to conserve diversity at all levels
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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
(a) Philippine eagle (b) Chinese river dolphin (c) Javan rhinoceros Figure 55.3 A hundred heartbeats from extinction
(a) Brown tree snake, intro- duced to Guam in cargo (b) Introduced kudzu thriving in South Carolina Figure 55.6 Two introduced species
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.
Small population Genetic drift Inbreeding Lower reproduction Higher mortality Loss of genetic variability Reduction in individual fitness and population adaptability Smaller population Figure 55.9 Processes culminating in an extinction vortex
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.
(b) Edges created by human activity. Pronounced edges (roads) surround clear-cuts in this photograph of a heavily logged rain forest in Malaysia. (a) Natural edges. Grasslands give way to forest ecosystems in Yellowstone National Park. Figure 55.14 Edges between ecosystems
Figure 55.15 Amazon rain forest fragments, isolated sections of forest ranging in area from 1 to 100 ha
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.
Nicaragua CARIBBEAN SEA Costa Rica National park land Buffer zone Panama PACIFIC OCEAN (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. Figure 55.19 Zoned reserves in Costa Rica
Equator Truckee River, Nevada Kissimmee River, Florida Figure 55.22 Restoration Ecology Worldwide