populations, r-species, k-species, mark & recapture methods and analysis; more slides at GoAPES (http://goapes.wikispaces.com).

1. POPULATION DYNAMICS,
CARRYING CAPACITY, AND
CONSERVATION BIOLOGY
The Walker School
Environmental Science

2. Population Ecology
The study of individual

species in relation to the
environment.
The field is concerned

with conservation and
focuses on Population and
Population Viability
Analysis (PVA)

3. Population Viability Analysis
A species-specific method of

risk assessment.
Brings together species

characteristics and
environmental variability to
forecast population health and
extinction risk.
Begins with the question: “Is this

species at risk of becoming
endangered? If so, why?”.
A research example may

include: “What are the effects
of industrial forestry on
biodiversity.”

4. WHAT ARE THE MAJOR
CHARACTERISTICS OF A
POPULATION?

5. Populations
A group of individuals of a single species that

simultaneously occupy the same general area.

6. Populations Under Study
Diseases (prions, viruses, bacteria)

Vegetation (crops, orchards, forests)

Terrestrial Animals (cattle, sheep, pigs, chickens)

Aquatic Organisms (fish, shrimp)

Humans


7. HIV Population in South Africa
Arcview GIS

8. Characteristics of Populations
Distribution

Numbers (size)

Age Structure

Density (#/area)

Celestichthys

9. WHAT IS BIOGEOGRAPHY?

10. Biogeography
The study of the size and

distribution of biodiversity
over space and time. It
aims to reveal where
organisms live, and at
what abundance.
Giant Pandas

11. Factors Explaining Species Distributions
Speciation

Extinction

Continental drift

Glaciations

(associated variations
in sea level, river
routes)
River capture


12. Speciation & Population Types
 Ranges
 PhysicalStructures
 Food Resources

13. Paleobiogeography
goes one step further

to include
paleogeographic data
and considerations of
plate tectonics.
Uses molecular

analyses and fossils to
determine the change
in a species over
millions of years.
Hominid Evolution

14. HOW ARE POPULATIONS
TRACKED?

15. Mark-Recapture Method
A method commonly used in ecology to estimate population

size and population vital rates (i.e., survival, movement, and
growth)

16. Lotek Wildlife GPS Monitors
http://www.lotek.com/

17. The Process
Researcher visits a study area and uses traps to
1.
capture a group of individuals alive.
Captured animals are marked with tags, collars,
2.
bands, or spots of dye and then is released
unharmed back into the environment.
Sufficient time is allowed to pass for the marked
3.
individuals to redistribute themselves among the
unmarked population.
Next, the researcher returns and captures another
4.
sample of individuals.

18. Analysis

19. WHAT FACTORS GOVERN
CHANGES IN POPULATION
SIZE?

20. Demography
The study of the vital statistics that affect population

size.
•Size
•Density
•Age Distribution
•Dispersion

21. Population Dispersion Patterns
Clumped Uniform Random
(elephants) (creosote bush) (dandelions)

22. Factors Affecting Distribution
Density Dependant Density Independent
Competition for Floods
 
Resources Hurricanes

Predation Unseasonable
 
Weather
Parasitism

Infectious Disease Fire
 
Clear Cutting

Pesticide Spraying


23. Changing and Clumping
Availability and variation

of resources
Provide protection in

numbers
Packs have a better

chance of obtaining food
Temporary groups for

mating

24. Factors that Govern Population Size
Crude Birth Rate (CBR)

Crude Death Rate (CDR)

Immigration

Emigration

Population Change = (births + immigration) – (deaths + emigration)

25. Population Age Structures

26. WHAT LIMITS POPULATION
GROWTH?

27. Resources and Competitors
Biotic Potential (r)

Ecosystem Carrying

Capacity (K)
Rate of Increase

Environmental

Resistance
Carrying Capacity

28. Population Growth Curves:
J-Curve & S-Curve
© 2004 Brooks/Cole – Thomson Learning
K
Population size (N)
Population size (N)
Time (t) Time (t)
Exponential Growth Logistic Growth

29. Population growth strives for dynamic equilibrium:
Logistic Growth of a Sheep
2.0
Number of sheep (millions)
1.5
1.0
.5
1800 1825 1850 1875 1900 1925
Year

30. Organisms can exceed their carrying capacity:
Exponential Growth and Crash of Reindeer
2,000
Number of reindeer
1,500
1,000
500
1910 1920 1930 1940 1950
Year

31. Reasons for Diebacks
Catastrophic Loss of Resources

Introduction of New Predator

Disease


32. WHAT KINDS OF POPULATION
CHANGE CURVES DO WE FIND
IN NATURE?

33. General Types of Population Curves in Nature © 2004 Brooks/Cole – Thomson Learning
Irregular
Stable
Number of individuals
Cyclic
Irruptive
Time

34. Cycles in Hare and Lynx
Populations
160
140 Hare
Population size (thousands)
120
Lynx
100
80
60
40
20
0
1845 1855 1865 1875 1885 1895 1905 1915 1925 1935
Year

35. Community Organization –
Trophic Cascade Model
Postulates that it is mainly predation that controls

community organization
Predators control herbivores


36. Community Organization –
Bottom-Up Model
Mineral nutrients control community organization

Nutrients control plant types and numbers

Plants control predators

Changes in this community are done by adding or

removing minerals

37. Activity: Radio Expeditions
Species Extinctions
Audio Evidence of Ivory-Billed Woodpecker

http://www.npr.org/templates/story/story.php?storyId=4814860

Audubon Bird Count, Lost Woodpecker Rediscovered

http://www.npr.org/templates/story/story.php?storyId=5067655

Slate's Explainer: Determining Species Extinction

http://www.npr.org/templates/story/story.php?storyId=5015201


38. Activity: Radio Expeditions
Species Extinctions Questions
Populations are classified by size, density, age distribution, and dispersion

type. Briefly explain each of these concepts and describe one
environmental factor that would limit the population growth of a bird
species.
Discuss the difference between an endangered and a threatened species.

Design a population count experiment to determine if a bird population is

threatened or endangered. Make sure to discuss how the study area was
selected and what method will be used to estimate population.
Discuss one biological intervention, economic incentive and one legislative

policy to restore an endangered bird population.
Discuss what technology could be used to periodically monitor the program.


39. WHAT TYPE OF
REPRODUCTIVE PATTERNS DO
SPECIES HAVE?

40. Sexual Partners Are Not Always Needed
Asexual Reproduction

Sexual Reproduction


41. Sexual Reproduction Methods
Semelparity

 Onetime reproductive event
Iteroparity

 Repeated reproduction

42. General Characteristics of r-Selected Species
cockroach dandelion
r-Selected Species
Many small offspring
Little or no parental care and protection of offspring
Early reproductive age
Most offspring die before reaching reproductive age
Small adults
Adapted to unstable climate and environmental
conditions
High population growth rate (r)
Population size fluctuates wildly above and below
carrying capacity (K)
Generalist niche
Low ability to compete
Early successional species

43. General Characteristics of k-Selected Species
K-Selected Species
elephant saguaro
Fewer, larger offspring
High parental care and protection of offspring
Later reproductive age
Most offspring survive to reproductive age
Larger adults
Adapted to stable climate and environmental
conditions
Lower population growth rate (r)
Population size fairly stable and usually close
to carrying capacity (K)
Specialist niche
High ability to compete
Late successional species

44. Carrying Capacity of Species
Carrying capacity
K
K species;
experience
Number of individuals
K selection
r species;
experience
r selection
Time

45. WHAT ROLE DOES GENETICS
PLAY IN THE SIZE OF
POPULATIONS?

46. Vulnerability of Populations
Founders Effect

Results from the migration of a population to a geographically

isolated area.
Demographic Bottleneck

Results from a natural catastrophe such as fire or a hurricane.

Genetic Drift

Results from random changes in the gene frequencies in a population.

Interbreeding

Results when individuals from a small population breed with each

other.

47. HOW DO ECOLOGISTS USE
LIFE TABLES AND
SURVIVORSHIP CURVES TO
MONITOR POPULATIONS?

48. Death Will Come:
Survivorship Curves
Late Loss

Early Loss
Percentage surviving (log scale)
100

Constant Loss

10
1
0
Age

49. Life Table
Life Expectancy at Birth of Epidemic Malaria Area in Papua New Guinea
An age-specific summary of the

survival pattern of a population.
Life tables are constructed by

following a cohort from birth to
death.
A cohort is a group of individuals

of the same age.
The table is constructed from the

number of individuals that die in
each age-group during a
defined time period.
Life tables are graphically

displayed in survivorship curves.

50. Geographical Information Systems
Used to Map Population Data
Captures, stores, analyzes,

manages, and presents data
that refers to or is linked to
location.
Geographic information system

technology can be used for
scientific investigations for the
environmental science,
environmental impact
assessment, urban planning and
other purposes.
Can be used for spacial

analysis and data modeling.