Download video slide - CARNES AP BIO

Chapter 56
Conservation Biology and
Restoration Ecology
PowerPoint Lectures for
Biology, Seventh Edition
Neil Campbell and Jane Reece
Lectures by Chris Romero
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Overview: The Biodiversity Crisis
• Overview: The Biodiversity Crisis
– Conservation biology integrates the following fields
to conserve biological diversity at all levels
• Ecology
• Evolutionary biology
• Physiology
• Molecular biology
• Genetics
• Behavioral ecology
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Restoration Ecology
• Restoration ecology applies ecological
principles
– In an effort to return degraded ecosystems to
conditions as similar as possible to their
natural state
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Losing Tropical Forests
• Tropical forests
– Contain some of the greatest concentrations of
species
– Are being destroyed at an alarming rate
Figure 55.1
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
The HUMAN Impact
• Throughout the biosphere, human activities are
altering ecosystem processes on which we and
other species depend!
• Rates of species extinction are difficult to
determine under natural conditions
• The current rate of species extinction is high
and 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
Genetic diversity in a vole population
– Ecosystem diversity
Species diversity in a coastal redwood ecosystem
Figure 55.2
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Community and ecosystem diversity
across the landscape of an entire region
Levels of Biodiversity
• Genetic diversity comprises
– The genetic variation within a population
– The genetic variation between populations
• Species diversity
– Is the variety of species in an ecosystem or throughout
the biosphere
• Ecosystem diversity
– Identifies the variety of ecosystems in the biosphere
– Is being affected by human activity
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Species Diversity
• An endangered species
– Is one that is in danger of becoming extinct
throughout its range
• Threatened species
– Are those that are considered likely to become
endangered in the foreseeable future
• Conservation biologists are concerned about
species loss
– Because of a number of alarming statistics
regarding extinction and biodiversity
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 many 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
• The loss of species
– Also means the loss of genes and genetic
diversity
• The enormous genetic diversity of organisms
on Earth
– Has the 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 the species they contain help sustain
human life on Earth
• Ecosystem services include
– Purification of air and water
– Detoxification and decomposition of wastes
– Cycling of nutrients
– Moderation of weather extremes
– And many others
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 single greatest threat to biodiversity
throughout the biosphere
• Massive destruction of habitat
– Has been brought about by many types of
human activity
• In almost all cases
– Habitat fragmentation and destruction leads to
loss of biodiversity
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Introduced Species
• Introduced species
– Are those that humans
move from the species’
native locations to new
geographic regions
(a) Brown tree
snake, introduced to Guam
in cargo
• Introduced species that gain
a foothold in a new habitat
– Usually disrupt their
adopted community
Figure 55.6a, b
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
(b) Introduced kudzu thriving in South Carolina
Overexploitation
• Overexploitation refers generally to the human
harvesting of wild plants or animals
– At rates exceeding the ability of populations of
those species to rebound
• The fishing industry
– Has caused significant reduction in populations
of certain game fish
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Disruption of Interaction Networks
• The extermination of keystone species by
humans
– Can lead to major changes in the structure of
communities
Figure 55.8
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Conservation Effort
• 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
• Conservation biologists who adopt the smallpopulation approach
– Study the processes that can cause very small
populations finally to become extinct
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
The Extinction Vortex
• A small population is prone to positivefeedback loops
– That draw the population down an extinction
vortex
Small
population
Inbreeding
Genetic
drift
Lower
reproduction
Higher
mortality
Reduction in
individual
fitness and
population
adaptability
Figure 55.9
Smaller
population
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Loss of
genetic
variability
The Extinction Vortex
• The key factor driving the extinction vortex
– Is the loss of the genetic variation necessary to
enable evolutionary responses to
environmental change
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Minimum Viable Population Size
• 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 meaningful estimate of MVP
– Requires a researcher to determine the effective
population size, which is based on the breeding size of
a population
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 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
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Case Study: Decline of the Red-Cockaded
Woodpecker
• Red-cockaded woodpeckers
– Require specific habitat factors for survival
– Had been forced into decline by habitat
destruction
(a) A red-cockaded woodpecker perches at the
entrance to its nest site in a longleaf pine.
Figure 55.13a–c
(b) Forest that can
sustain red-cockaded
woodpeckers has
low undergrowth.
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
(c) Forest that cannot sustain red-cockaded
woodpeckers has high, dense undergrowth that
impacts the woodpeckers’ access to feeding grounds.
Case Study: Decline of the Red-Cockaded Woodpecker
• In a study where breeding cavities were
constructed
– New breeding groups formed only in these
sites
• On the basis of this experiment
– A combination of habitat maintenance and
excavation of new breeding cavities has
enabled a once-endangered species to
rebound
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Weighing Conflicting Demands
• Conserving species often requires resolving
conflicts
– Between the habitat needs of endangered
species and human demands
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Regional Conservation
• Landscape and regional conservation aim to
sustain entire areas of biodiversity
• In recent years, conservation biology has
attempted to sustain the biodiversity of entire
communities, ecosystems, and landscapes
• One goal of landscape ecology, of which
ecosystem management is part
– Is to understand past, present, and future
patterns of landscape use and to make
biodiversity conservation part of land-use
planning
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Fragmentation and Edges
• The structure of a
landscape can strongly
influence biodiversity
• The boundaries, or
edges, between
ecosystems are defining
features of landscapes
• As habitat fragmentation
increases and edges
become more extensive,
biodiversity tends to
Figure 55.14a, b
decrease
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
(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.
Biological Hot Spots
• Much of the focus on establishing protected
areas
– Has been on hot spots of biological diversity
• Biodiversity hot spots are obviously good
choices for nature reserves
– But identifying them is not always easy
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Finding 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
Terrestrial
biodiversity
hot spots
Equator
Figure 55.17
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Philosophy of Nature Reserves
• Nature reserves are biodiversity islands
– In a sea of habitat degraded to varying
degrees by human activity
• One argument for extensive reserves
– Is that large, far-ranging animals with lowdensity populations require extensive habitats
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Restoration Ecology
• Restoration ecology attempts to restore degraded
ecosystems to a more natural state
• The larger the area disturbed
– The longer the time that is required for recovery
• One of the basic assumptions of restoration ecology
– Is that most environmental damage is reversible
• Two key strategies in restoration ecology
– Are bioremediation and augmentation of ecosystem
processes
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Bioremediation & Biological Augmentation
• Bioremediation
– Is the use of living organisms to detoxify
ecosystems
• 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 scientists to consider alternative
solutions and adjust approaches based on
experience
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Sustainable Use
• Sustainable development seeks to improve the
human condition while conserving biodiversity
• Facing increasing loss and fragmentation of
habitats
– How can we best manage Earth’s resources?
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Sustainable Biosphere Initiative
• The goal of this initiative is to define and
acquire the basic ecological information
necessary
– For the intelligent and responsible
development, management, and conservation
of Earth’s resources
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Biophilia and the Future of the Biosphere
• Our modern lives
– Are very different from those of early humans
who hunted and gathered and painted on cave
walls
Figure 55.24a
(a) Detail of animals in a Paleolithic mural, Lascaux, France
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Biophilia and the Future of the Biosphere
• But our behavior
– Reflects remnants of our ancestral attachment
to nature and the diversity of life, the concept
of biophilia
Figure 55.24b
(b) Biologist Carlos Rivera Gonzales examining a tiny tree frog in
Peru
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Biophilia and the Future of the Biosphere
• Our innate sense of connection to nature
– May eventually motivate a realignment of our
environmental priorities
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings