Chapter 38
Conservation Biology
Introduction: Saving the Tiger
A.)
Conservation biology is a goal-oriented science
B.)
Conservation biology touches all levels of ecology
– It seeks to counter the biodiversity crisis
– It can focus on a single species
– It can also protect many species at once by preserving habitats and
ecosystems
– From a single tiger
– To the forest it roams
THE BIODIVERSITY CRISIS
38.1 Biodiversity is a vital resource that is being lost
A.) Scientists estimate that the Earth has anywhere from 1.8 to
200 million species
– It is difficult to estimate species loss
– Species loss may be 1,000 times higher than in the past 100,000 years
B.)
Scientists are concerned about the ecological changes that
underlie biodiversity loss
– Ecologists point out the “services” provided by the biodiversity of
ecosystems
38.2 Biodiversity includes genetic, species, and ecosystem
diversity
A.)
Biodiversity has three levels
B.)
Endangered species
– Genetic diversity
– Species diversity
– Ecosystem diversity
– One that is “in danger of extinction throughout all or a significant portion
of its range”
– Protected by Endangered Species Act
C.)
Threatened species
D.)
93% of coral reefs were damaged by human activities
E.)
40–50% of the reefs are home to one-third of marine fish
species
F.)
These fish could be lost in the next 30 to 40 years
– Those likely to become endangered in the foreseeable future
38.3 Habitat destruction, invasive species, and overexploitation
are major threats to biodiversity
A.)
B.)
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Human alteration of habitats poses the greatest threat to
biodiversity
Habitation alteration is caused by
Agriculture
Urban development
Forestry
Mining
Environmental pollution
C.)
Invasive species rank behind habitat destruction as a threat
to biodiversity
D.)
Invasive species
E.)
Overexploitation is the third major threat to biodiversity
– Compete with native species
– Prey on native species
– Parasitize native species
– Overharvesting has threatened
– Rare trees
– Fish
– Bison
F.)
Hunting of wild animals for bushmeat is depleting
biodiversity worldwide
38.4 CONNECTION: Pollution of the environment compounds
our impact on other species
A.)
The global water cycle can transport pollutants
B.)
Gradually thinning ozone layer
C.)
Nutrient pollution from fertilizer and wastes
D.)
Pollutants in a food chain can lead to biological
magnification
– Pesticides used on land
– Sulfur and nitrogen oxides emitted into the atmosphere
– Release of chlorofluorocarbons from aerosol cans and manufacturing
– Linked to summer “dead zone” in the Gulf of Mexico
38.5 CONNECTION: Rapid warming is changing the global
climate
A.)
The scientific debate about global warming is over
– Global temperature has risen
– 0.8°C in the last 100 years
– 0.6°C of that increase occurred in the last three decades
– 2 to 4.5°C increases are likely by the end of the 21st century
B.)
Global warming most evident in arctic
– Shrinking sea ice
– Thinning ice sheets
– Melting permafrost
38.6 CONNECTION: Human activities are responsible for
rising concentrations of greenhouse gases
A.)
Atmospheric CO2 did not exceed 300 ppm for 650,000 years
B.)
Atmospheric CO2 is approximately 385 ppm today
C.)
High levels of methane and nitrous oxide also trap heat
38.7 Global climate change affects biomes, ecosystems,
communities, and populations
A.)
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Terrestrial biomes determined by temperature and rainfall
Changing as a consequence of global warming
Distributions of populations and species also changing
Disappearance of many species being caused by changing climate
Climate change affects seasonal events in some plants and animals
38.8 EVOLUTION CONNECTION: Global climate change is
an agent of natural selection
A.)
Global climate change drives natural selection of some
organisms
– Most of this selection is attributed to phenotypic plasticity
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B.)
Altering phenotype in response to environmental conditions
Within the normal range of genetic expression
Can involve genetic shifts that change a species
Prevents extinction of some species
Red squirrels in Canada
– Natural selection to coordinate breeding time with food availability
CONSERVATION BIOLOGY
AND RESTORATION ECOLOGY
38.9 Protecting endangered populations is one goal of
conservation biology
A.)
Habitat loss
– Population fragmentation
– A harmful effect of habitat loss
– Splitting and isolation of portions of populations
– Can lead to extinctions
B.)
Proactive conservation strategies attempt to stop declines in
populations
– Recovery of the red-cockaded woodpecker
– From near-extinction to sustainable populations
– Results from providing its key habitat factors
38.10 Sustaining ecosystems and landscapes is a conservation
priority
A.)
Conservation biology priority
– Past efforts
– Saving individual species
– Today
– Biodiversity of ecosystems
B.)
Landscape ecology
C.)
Edges can fragment ecosystems
D.)
Fragmentation is corrected with movement corridors
– Dynamics of a collection of ecosystems
38.11 Protected areas are established to slow the loss of
biodiversity
A.)
Conservation biology focuses on biodiversity hot spots
B.)
Hot spot designation favors the most noticeable organisms
C.)
Migratory species pose a special problem for conservationists
D.)
Reserves are set up to protect biodiversity
– Have a large number of endangered and threatened species
– Have a concentration of endemic species
– Monarch butterflies occupy many areas
– Sea turtles travel great distances
– 7% of world’s land is in various forms of reserves
38.12 Zoned reserves are an attempt to reverse ecosystem
disruption
A.)
Zoned reserve
– Extensive region of land with one or more areas undisturbed by humans
– Contributes to sustainable development
– Long-term prosperity of human societies and the ecosystems
– Provide an economic base for people living there
B.)
Zoned reserves are used in Costa Rican conservation
38.13 CONNECTION: The Yellowstone to Yukon
Conservation Initiative seeks to preserve biodiversity by
A.)
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connecting protected areas
Yellowstone to Yukon Conservation Initiative
Created a string of parks and reserves
3,200-km wildlife corridor
Alaska across Canada to northern Wyoming
Included introduction of wolf populations
Sparked angry protests from ranchers
38.14 CONNECTION: The study of how to restore degraded
habitats is a developing science
A.)
Restoration ecology
B.)
Restoring environments
– Uses ecological principles to restore environments
– Bioremediation
– Using organisms to detoxify polluted ecosystems
– Replanting native vegetation
– Repairing waterways and wetlands
38.15 Sustainable development is an ultimate goal
A.)
Biosphere is made of complex interconnections
– Sensible decisions needed to conserve these networks
– Must work for a sustainable future
– Sustainable development depends on continued research and application
You should now be able to
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Explain why biodiversity must be protected
Describe the three components of biodiversity
Explain the major factors that threaten biodiversity
Explain the consequences of global climate change
Describe major strategies used in conservation biology
Explain the principles of sustainable conservation practices