Conservation Biology and Restoration Ecology Chapter 55

Three Levels of Biodiversity Three Levels of Biodiversity

Genetic Diversity Genetic differences within a population Genetic variations between populations Genetic differences within a population Genetic variations between populations

Species Diversity Is the variety of species in an ecosystem or throughout the biosphere

Conservation biologists are concerned about species loss –Because of a number of alarming statistics regarding extinction and biodiversity

Ecosystem Diversity Variety of ecosystems in the biosphere The local extinction of one species can have a negative impact on the overall species richness of the community Human activity is affecting ecosystem diversity Variety of ecosystems in the biosphere The local extinction of one species can have a negative impact on the overall species richness of the community Human activity is affecting ecosystem diversity

Biophilia--our sense of connection to nature and other forms of life

Ecosystem services Ecosystem services encompass all the processes –Through which natural ecosystems and the species they contain help sustain human life on Earth Ecosystem services encompass all the processes –Through which natural ecosystems and the species they contain help sustain human life on Earth

Includes… –Purification of air and water –Detoxification and decomposition of wastes –Cycling of nutrients –Moderation of weather extremes –And many others –Purification of air and water –Detoxification and decomposition of wastes –Cycling of nutrients –Moderation of weather extremes –And many others

Major threats to biodiversity Most species loss can be traced to four major threats –Habitat destruction –Introduced species –Overexploitation –Disruption of “interaction networks” Most species loss can be traced to four major threats –Habitat destruction –Introduced species –Overexploitation –Disruption of “interaction networks”

Habitat Destruction Human alteration of habitat –Is the single greatest threat to biodiversity throughout the biosphere Massive destruction of habitat –Has been brought about by many types of human activity Human alteration of habitat –Is the single greatest threat to biodiversity throughout the biosphere Massive destruction of habitat –Has been brought about by many types of human activity

Introduced Species Those that humans move, either intentionally or accidentally, from the species’ native locations to new geographic regions

Introduced species… That gain foothold usually disrupt their adopted community, often by preying on native organisms or outcompeting them for resources

Overexploitation Human harvesting of wild plants or animals at rates exceeding the ability of population of those species rebound Figure 55.7

Disruption of Interaction Networks The extinction of one species can doom others, particularly when the extinction involves a keystone species

Concept 55.2: Population conservation focuses on population size, genetic diversity, and critical habitat Two approaches: Conservation biologists who adopt the small- population approach – Study the processes that can cause very small populations finally to become extinct

Extinction Vortex Small pops. Prone to This positive feedback Loop that draw pop Down an extinction vortex Small pops. Prone to This positive feedback Loop that draw pop Down an extinction vortex Small population Inbreeding Genetic drift Lower reproduction Higher mortality Loss of genetic variability Reduction in individual fitness and population adaptability Smaller population Figure 55.9

The key factor driving the extinction vortex –Is the loss of the genetic variation necessary to enable evolutionary responses to environmental change The key factor driving the extinction vortex –Is the loss of the genetic variation necessary to enable evolutionary responses to environmental change

The minimum viable population (MVP) –Is the minimum population size at which a species is able to sustain its numbers and survive The minimum viable population (MVP) –Is the minimum population size at which a species is able to sustain its numbers and survive

A population viability analysis (PVA) –Predicts a population’s chances for survival over a particular time –Factors in the MVP of a population A population viability analysis (PVA) –Predicts a population’s chances for survival over a particular time –Factors in the MVP of a population

Declining Population Approach The declining-population approach –Focuses on threatened and endangered populations that show a downward trend, regardless of population size –Emphasizes the environmental factors that caused a population to decline in the first place The declining-population approach –Focuses on threatened and endangered populations that show a downward trend, regardless of population size –Emphasizes the environmental factors that caused a population to decline in the first place

The declining-population approach –Requires that population declines be evaluated on a case-by-case basis –Involves a step-by-step proactive conservation strategy The declining-population approach –Requires that population declines be evaluated on a case-by-case basis –Involves a step-by-step proactive conservation strategy

Landscape and regional conservation aim to sustain entire biotas

Landscape Structure and Biodiversity The structure of a landscape can strongly influence biodiversity The boundaries, or edges, between ecosystems –Are defining features of landscapes The structure of a landscape can strongly influence biodiversity The boundaries, or edges, between ecosystems –Are defining features of landscapes (a) Natural edges. Grasslands give way to forst 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 55.14a, b

As habitat fragmentation increases and edges become more extensive, biodiversity tends to decrease

A movement corridor –Is a narrow strip of quality habitat connecting otherwise isolated patches –Can promote dispersal and help sustain populations A movement corridor –Is a narrow strip of quality habitat connecting otherwise isolated patches –Can promote dispersal and help sustain populations

Biodiversity Hot Spots A biodiversity hot spot is a relatively small area –With an exceptional concentration of endemic species and a large number of endangered and threatened species A biodiversity hot spot is a relatively small area –With an exceptional concentration of endemic species and a large number of endangered and threatened species Terrestrial biodiversity hot spots Equator Figure 55.17

Nature reserves are biodiversity islands –In a sea of habitat degraded to varying degrees by human activity The zoned reserve model recognizes that conservation efforts –Often involve working in landscapes that are largely human dominated Nature reserves are biodiversity islands –In a sea of habitat degraded to varying degrees by human activity The zoned reserve model recognizes that conservation efforts –Often involve working in landscapes that are largely human dominated

Concept 55.4: Restoration ecology attempts to restore degraded ecosystems to a more natural state

Bioremediation –Is the use of living organisms to detoxify ecosystems Bioremediation –Is the use of living organisms to detoxify ecosystems

Biological augmentation –Uses organisms to add essential materials to a degraded ecosystem Biological augmentation –Uses organisms to add essential materials to a degraded ecosystem

The newness and complexity of restoration ecology –Require scientists to consider alternative solutions and adjust approaches based on experience The newness and complexity of restoration ecology –Require scientists to consider alternative solutions and adjust approaches based on experience

Concept 55.5: Sustainable development seeks to improve the human condition while conserving biodiversity

Sustainable Biosphere Initiative Acquire the ecological information needed for the development, management, and conservation

Biophilia and the Future of the Biosphere Our innate sense of connection to nature may eventually motivate a realignment of our environmental priorities