Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Biology 102 Week 11 Conservation Biology and Restoration Ecology
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Overview: The Biodiversity Crisis Conservation biology integrates these fields: – Ecology – Evolutionary biology – Physiology – Molecular biology – Genetics – Behavioral ecology
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Restoration ecology applies ecological principles to return degraded ecosystems to conditions as similar as possible to their natural state
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Tropical forests containing some of the greatest concentrations of species are being destroyed at an alarming rate Throughout the biosphere, human activities are altering ecosystem processes on which we and other species depend
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Concept 55.1: Human activities threaten Earth’s biodiversity Rates of species extinction are difficult to determine under natural conditions The high rate of species extinction is largely a result of ecosystem degradation by humans Humans are threatening Earth’s biodiversity
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Three Levels of Biodiversity Biodiversity has three main components: – Genetic diversity – Species diversity – Ecosystem diversity
LE 55-2 Genetic diversity in a vole population Species diversity in a coastal redwood ecosystem Community and ecosystem diversity across the landscape of an entire region
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Genetic Diversity Genetic diversity comprises genetic variation within a population and between populations
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Species Diversity Species diversity is the variety of species in an ecosystem or throughout the biosphere An endangered species is in danger of becoming extinct throughout its range A threatened species is likely to become endangered in the future
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Conservation biologists are concerned about species loss because of alarming statistics regarding extinction and biodiversity Researchers estimate that at current rates of extinction more than half of current plant and animal species will disappear in this century Harvard biologist E. O. Wilson has identified the Hundred Heartbeat Club: species with fewer than 100 individuals
LE 55-3 Philippine eagle Chinese river dolphin Javan rhinoceros
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Ecosystem Diversity Human activity is reducing ecosystem diversity, the variety of ecosystems in the biosphere
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Biodiversity and Human Welfare Human biophilia allows us to recognize the value of biodiversity for its own sake Species diversity brings humans practical benefits
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Benefits of Species and Genetic Diversity Many pharmaceuticals contain substances originally derived from plants For example, the rosy periwinkle contains alkaloids that inhibit cancer growth
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The loss of species also means loss of genes and genetic diversity The enormous genetic diversity of organisms has potential for great human benefit
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Ecosystem Services Ecosystem services encompass all the processes through which natural ecosystems and their species help sustain human life Some examples of ecosystem services: – Purification of air and water – Detoxification and decomposition of wastes – Cycling of nutrients – Moderation of weather extremes
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Four Major Threats to Biodiversity Most species loss can be traced to four major threats: – Habitat destruction – Introduced species – Overexploitation – Disruption of “interaction networks”
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Habitat Destruction Human alteration of habitat is the greatest threat to biodiversity throughout the biosphere Many natural landscapes have been broken up, fragmenting habitat into small patches In almost all cases, habitat fragmentation and destruction lead to loss of biodiversity
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Introduced Species Introduced species are those that humans move from native locations to new geographic regions Introduced species that gain a foothold in a new habitat usually disrupt their adopted community
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Sometimes humans introduce species by accident, as in case of the brown tree snake arriving in Guam as a cargo ship “stowaway”
LE 55-6 Brown tree snake, intro- duced to Guam in cargo. Introduced kudzu thriving in South Carolina
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Humans have deliberately introduced some species with good intentions but disastrous effects An example is the introduction of kudzu in the southern United States
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Overexploitation Overexploitation is human harvesting of wild plants or animals at rates exceeding the ability of populations of those species to rebound For example, the fishing industry has greatly reduced populations of some game fish, such as bluefin tuna
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Disruption of Interaction Networks Extermination of keystone species by humans can lead to major changes in community structure
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Concept 55.2: Population conservation focuses on population size, genetic diversity, and critical habitat Biologists focusing on conservation at the population and species levels follow two main approaches: – The small-population approach – The declining population approach
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Small-Population Approach The small-population approach studies processes that can make small populations become extinct
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Extinction Vortex A small population is prone to positive-feedback loops that draw it down an extinction vortex
LE 55-9 Reduction in individual fitness and population adaptability Small population Loss of genetic variability Higher mortality Genetic drift Inbreeding Lower reproduction Smaller population
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The key factor driving the extinction vortex is loss of the genetic variation necessary to enable evolutionary responses to environmental change
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Case Study: The Greater Prairie Chicken and the Extinction Vortex Populations of the greater prairie chicken were fragmented by agriculture and later found to exhibit decreased fertility To test the extinction vortex hypothesis, scientists imported genetic variation by transplanting birds from larger populations The declining population rebounded, confirming it had been on its way down an extinction vortex
LE Population dynamics Year Number of male birds Hatching rate 1970–74 Years Eggs hatched (%) –791980–841985– –97
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Minimum Viable Population Size Minimum viable population (MVP) is the minimum population size at which a species can survive The MVP factors into a population viability analysis (PVA), which predicts a population’s chances for survival over a particular time
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Effective Population Size A meaningful estimate of MVP requires determining the effective population size, which is based on the population’s breeding size
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Case Study: Analysis of Grizzly Bear Populations One of the first population viability analyses was conducted as part of a long-term study of grizzly bears in Yellowstone National Park
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This study showed that the grizzly bear population has grown substantially in the past 20 years
LE Year Number of individuals Females with cubs Cubs
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Steps for Analysis and Intervention The declining-population approach – Requires that declines in population be evaluated on a case-by-case basis – Involves a step-by-step proactive conservation strategy
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Case Study: Decline of the Red-Cockaded Woodpecker Red-cockaded woodpeckers had been forced into decline by habitat destruction
LE A red-cockaded woodpecker perches at the entrance to its nest site in a longleaf pine. Forest that can sustain red- cockaded woodpeckers has low undergrowth. Forest that cannot sustain red-cockaded woodpeckers has high, dense undergrowth that impacts the woodpeckers’ access to feeding grounds.
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings In a study where breeding cavities were constructed, new breeding groups formed only in these sites Based on this experiment, a combination of habitat maintenance and excavation of breeding cavities enabled this endangered species to rebound
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Weighing Conflicting Demands Conserving species often requires resolving conflicts between habitat needs of endangered species and human demands
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Concept 55.3: Landscape and regional conservation aim to sustain entire biotas Conservation biology has attempted to sustain the biodiversity of entire communities, ecosystems, and landscapes Ecosystem management is part of landscape ecology, which seeks to make biodiversity conservation part of land-use planning
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Landscape Structure and Biodiversity The structure of a landscape can strongly influence biodiversity
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Fragmentation and Edges The boundaries, or edges, between ecosystems are defining features of landscapes Some edges are natural, but some are created by human activity
LE Natural edges. Grasslands give way to forest ecosystems in Yellowstone National Park. Edges created by human activity. Pronounced edges (roads) surround clear-cuts in this photograph of a heavily logged rain forest in Malaysia.
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Biodiversity decreases as habitat fragmentation increases and edges become more extensive Research led to discovery of two groups of species, those that live in forest edge habitats and those that live in the forest interior
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Corridors That Connect Habitat Fragments A movement corridor is a narrow strip of quality habitat connecting otherwise isolated patches Movement corridors promote dispersal and help sustain populations In areas of heavy human use, artificial corridors are sometimes constructed
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Establishing Protected Areas Conservation biologists apply understanding of ecological dynamics in establishing protected areas to slow the loss of biodiversity Much of their focus has been on hot spots of biological diversity
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Finding Biodiversity Hot Spots A biodiversity hot spot is a relatively small area with a great concentration of endemic species and many endangered and threatened species Biodiversity hot spots are good choices for nature reserves, but identifying them is not always easy Video: Coral Reef Video: Coral Reef
LE Terrestrial biodiversity hot spots Equator
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Philosophy of Nature Reserves Nature reserves are biodiversity islands in a sea of habitat degraded by human activity One argument for extensive reserves is that large, far-ranging animals with low-density populations require extensive habitats In some cases, reserves are smaller than the area needed to sustain a population
LE Kilometers ° Yellowstone National Park Madison R. Idaho Montana Gallatin R. 42° 41° 40° Grand Teton National Park Wyoming Snake R. Montana Idaho Wyoming Yellowstone R. Shoshone R.
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Zoned Reserves The zoned reserve model recognizes that conservation often involves working in landscapes that are largely human dominated Zoned reserves are often established as “conservation areas”
LE 55-19a National park land Buffer zone PACIFIC OCEAN CARIBBEAN SEA Nicaragua Costa Rica Panama Boundaries of the zoned reserves are indicated by black outlines.
LE 55-19b Local schoolchildren marvel at the diversity of life in one of Costa Rica’s reserves.
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Some zoned reserves in the Fiji islands are closed to fishing, which actually improves fishing success in nearby areas
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Concept 55.4: Restoration ecology attempts to restore degraded ecosystems to a more natural state Given enough time, biological communities can recover from many types of disturbances Recovery time depends more on the spatial scale than on the type of disturbance Whether a disturbance is natural or caused by humans seems to make little difference in this size-time relationship
LE Natural disasters Groundwater exploitation Industrial pollution Meteor strike Human-caused disasters Natural OR human- caused disasters , Recovery time (years) (log scale) –3 10 –1 10 – Spatial scale (km 2 ) (log scale) 1, Salination Flood Urbanization Tsunami Oil spill Modern agriculture Forest fire Nuclear bomb Acid rain Volcanic eruption Lightning strike Tree fall Land- slide Slash & burn
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings A basic assumption of restoration ecology is that most environmental damage is reversible Two key strategies are bioremediation and augmentation of ecosystem processes
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Bioremediation Bioremediation is the use of living organisms to detoxify ecosystems
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Biological Augmentation Biological augmentation uses organisms to add essential materials to a degraded ecosystem
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Exploring Restoration The newness and complexity of restoration ecology require considering alternative solutions and adjusting approaches based on experience
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Concept 55.5: Sustainable development seeks to improve the human condition while conserving biodiversity Facing increasing loss and fragmentation of habitats, how can we manage Earth’s resources?
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Sustainable Biosphere Initiative The goal of the Sustainable Biosphere Initiative is to define and acquire basic ecological information for responsible development, management, and conservation of Earth’s resources Sustainable development is the long-term prosperity of human societies and the ecosystems that support them
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Case Study: Sustainable Development in Costa Rica Costa Rica’s conservation of tropical biodiversity involves partnerships between the government, other organizations, and private citizens Human living conditions in Costa Rica have improved along with ecological conservation
LE Life expectancy Infant mortality (per 1,000 live births) Life expectancy (years) Infant mortality Year
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Biophilia and the Future of the Biosphere Our lives differ greatly from early humans who hunted and gathered and painted on cave walls
LE Detail of animals in a 36,000-year-old cave painting, Lascaux, FranceBiologist Carlos Rivera Gonzales examining a tiny tree frog in Peru
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings But our behavior reflects remnants of our ancestral attachment to nature and the diversity of life—the concept of biophilia Our sense of connection to nature may motivate realignment of our environmental priorities