1. Conservation Biology and Restoration Ecology
Chapter 55
Conservation Biology and Restoration Ecology

2. 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

3. Restoration ecology applies ecological principles
In an effort to return degraded ecosystems to conditions as similar as possible to their natural state

4. Tropical forests
Contain some of the greatest concentrations of species
Are being destroyed at an alarming rate
Figure 55.1

5. Throughout the biosphere, human activities
Are altering ecosystem processes on which we and other species depend

6. Concept 55.1: Human activities threaten Earth’s biodiversity
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

7. The Three Levels of Biodiversity
Biodiversity has three main components
Genetic diversity
Species diversity
Ecosystem diversity
Genetic diversity in a vole population
Species diversity in a coastal redwood ecosystem
Community and ecosystem diversity
across the landscape of an entire region
Figure 55.2

8. Genetic diversity comprises
The genetic variation within a population
The genetic variation between populations

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

10. An endangered species Threatened 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

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

12. Harvard biologist E. O. Wilson has identified the Hundred Heartbeat Club
Species that number fewer than 100 individuals and are only that many heartbeats from extinction
(a) Philippine eagle
(b) Chinese river dolphin
(c) Javan rhinoceros
Figure 55.3a–c

13. Ecosystem Diversity Ecosystem diversity
Identifies the variety of ecosystems in the biosphere
Is being affected by human activity

14. 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

15. Benefits of Species and Genetic Diversity
Many pharmaceuticals
Contain substances originally derived from plants
Figure 55.4

16. The enormous genetic diversity of organisms on Earth
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

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

18. Ecosystem services include
Purification of air and water
Detoxification and decomposition of wastes
Cycling of nutrients
Moderation of weather extremes
And many others

19. Four Major Threats to Biodiversity
Most species loss can be traced to four major threats
Habitat destruction
Introduced species
Overexploitation
Disruption of “interaction networks”

20. Human alteration of habitat
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

21. Many natural landscapes have been broken up
Fragmenting habitat into small patches
Figure 55.5

22. In almost all cases
Habitat fragmentation and destruction leads to loss of biodiversity

23. Introduced Species Introduced species
Are those that humans move from the species’ native locations to new geographic regions

24. (b) Introduced kudzu thriving in South Carolina
Introduced species that gain a foothold in a new habitat
Usually disrupt their adopted community
(a) Brown tree snake, intro duced to Guam in cargo
(b) Introduced kudzu thriving in South Carolina
Figure 55.6a, b

25. 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

26. The fishing industry
Has caused significant reduction in populations of certain game fish
Figure 55.7

27. Disruption of Interaction Networks
The extermination of keystone species by humans
Can lead to major changes in the structure of communities
Figure 55.8

28. 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

29. Small-Population Approach
Conservation biologists who adopt the small-population approach
Study the processes that can cause very small populations finally to become extinct

30. A small population is prone to positive-feedback loops
The Extinction Vortex
A small population is prone to positive-feedback loops
That draw the population down an extinction vortex
Small
population
Inbreeding
Genetic
drift
Lower reproduction
Higher mortality
Loss of
genetic
variability
Reduction in
individual
fitness and
adaptability
Smaller
Figure 55.9

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

32. 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

33. As a test of the extinction vortex hypothesis
Scientists imported genetic variation by transplanting birds from larger populations

34. (a) Population dynamics
The declining population rebounded
Confirming that it had been on its way down an extinction vortex
EXPRIMENT
Researchers observed that the population collapse of the greater prairie chicken was mirrored in a reduction in fertility, as measured by the hatching rate of eggs. Comparison of DNA samples from the Jasper County, Illinois, population with DNA from feathers in museum specimens showed that genetic variation had declined in the study population. In 1992, researchers began experimental translocations of prairie chickens from Minnesota, Kansas, and Nebraska in an attempt to increase genetic variation.
RESULTS
After translocation (blue arrow), the viability of eggs rapidly improved, and the population rebounded.
CONCLUSION
The researchers concluded that lack of genetic variation had started the Jasper County population of prairie chickens down the extinction vortex.
Number of male birds
(a) Population dynamics
(b) Hatching rate
200
150
100 50
1970
1975
1980
1985
1990
1995
2000
Year
Eggs hatched (%) 90 80 70 60 40 30
Years
Figure 55.10

35. 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

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

37. Effective Population Size
A meaningful estimate of MVP
Requires a researcher to determine the effective population size, which is based on the breeding size of a population

38. 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
Figure 55.11

39. This study has shown that the grizzly bear population
Has grown substantially in the past 20 years
Number of individuals
150
100 50
1973
1982
1991
2000
Females with cubs
Cubs
Year
Figure 55.12

40. 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

41. Steps for Analysis and Intervention
The declining-population approach
Requires that population declines be evaluated on a case-by-case basis
Involves a step-by-step proactive conservation strategy

42. 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.
(b) Forest that can sustain red-cockaded woodpeckers has low undergrowth.
(c) Forest that cannot sustain red-cockaded woodpeckers has high, dense undergrowth that impacts the woodpeckers’ access to feeding grounds.
Figure 55.13a–c

43. 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

44. Weighing Conflicting Demands
Conserving species often requires resolving conflicts
Between the habitat needs of endangered species and human demands

45. In recent years, conservation biology
Concept 55.3: Landscape and regional conservation aim to sustain entire biotas
In recent years, conservation biology
Has attempted to sustain the biodiversity of entire communities, ecosystems, and landscapes

46. 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

47. Landscape Structure and Biodiversity
The structure of a landscape
Can strongly influence biodiversity

48. Fragmentation and Edges
The boundaries, or edges, between ecosystems
Are defining features of landscapes
(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.
Figure 55.14a, b

49. As habitat fragmentation increases
And edges become more extensive, biodiversity tends to decrease

50. Research on fragmented forests has led to the discovery of two groups of species
Those that live in forest edge habitats and those that live in the forest interior
Figure 55.15

51. Corridors That Connect Habitat Fragments
A movement corridor
Is a narrow strip of quality habitat connecting otherwise isolated patches

52. In areas of heavy human use
Artificial corridors are sometimes constructed
Figure 55.16

53. Movement corridors
Promote dispersal and help sustain populations

54. Establishing Protected Areas
Conservation biologists are applying their understanding of ecological dynamics
In establishing protected areas to slow the loss of biodiversity

55. Much of the focus on establishing protected areas
Has been on hot spots of biological diversity

56. 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

57. Biodiversity hot spots are obviously good choices for nature reserves
But identifying them is not always easy

58. 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 low-density populations require extensive habitats

59. In some cases
The size of reserves is smaller than the actual area needed to sustain a population
Biotic boundary for
short-term survival;
MVP is 50 individuals.
long-term survival;
MVP is 500 individuals.
Grand Teton
National Park
Wyoming
Idaho
43
42
41
40 50
100
Kilometers
Snake R.
Yellowstone
National
Park
Shoshone R.
Montana
Madison R.
Gallatin R.
Yellowstone R.
Figure 55.18

60. The zoned reserve model recognizes that conservation efforts
Zoned Reserves
The zoned reserve model recognizes that conservation efforts
Often involve working in landscapes that are largely human dominated

61. (a) Boundaries of the zoned reserves are indicated by black outlines.
Are often established as “conservation areas”
(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.
Nicaragua
Costa
Rica
Panama
National park land
Buffer zone
PACIFIC OCEAN
CARIBBEAN SEA
Figure 55.19a, b

62. Some zoned reserves in the Fiji islands are closed to fishing
Which actually helps to improve fishing success in nearby areas
Figure 55.20

63. The larger the area disturbed
Concept 55.4: 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

64. Human-caused disasters
Whether a disturbance is natural or caused by humans
Seems to make little difference in this size-time relationship
Recovery time (years)
(log scale)
104
1,000
100 10 1
103
102
101
Natural disasters
Human-caused disasters
Natural OR human-
caused disasters
Meteor
strike
Groundwater
exploitation
Industrial
pollution
Urbanization
Salination
Modern
agriculture
Flood
Volcanic
eruption
Acid
rain
Forest
fire
Nuclear
bomb
Tsunami
Oil
spill
Slash
& burn
Land-
slide
Tree
fall
Lightning
Spatial scale (km2)
Figure 55.21

65. 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

66. Bioremediation Bioremediation
Is the use of living organisms to detoxify ecosystems

67. Biological Augmentation
Uses organisms to add essential materials to a degraded ecosystem

68. Exploring Restoration
The newness and complexity of restoration ecology
Require scientists to consider alternative solutions and adjust approaches based on experience

69. Kissimmee River, Florida.
Exploring restoration worldwide
Truckee River, Nevada.
Kissimmee River, Florida.
Equator
Figure 55.22

70. Tropical dry forest, Costa Rica.
Succulent Karoo, South Africa.
Rhine River, Europe.
Coastal Japan.
Figure 55.22

71. Facing increasing loss and fragmentation of habitats
Concept 55.5: 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?

72. 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

73. Case Study: Sustainable Development in Costa Rica
Costa Rica’s success in conserving tropical biodiversity
Has involved partnerships between the government, other organizations, and private citizens

74. Human living conditions in Costa Rica
Have improved along with ecological conservation
Infant mortality (per 1,000 live births)
200
150
100 50
1900
1950
2000 80 70 60 40 30
Year
Life expectancy
Infant mortality
Life expectancy (years)
Figure 55.23

75. 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
(a) Detail of animals in a Paleolithic mural, Lascaux, France
Figure 55.24a

76. But our behavior
Reflects remnants of our ancestral attachment to nature and the diversity of life, the concept of biophilia
(b) Biologist Carlos Rivera Gonzales examining a tiny tree frog in Peru
Figure 55.24b

77. Our innate sense of connection to nature
May eventually motivate a realignment of our environmental priorities