Measuring Biodiversity Credits to the owner of this ppt

1. Measuring Biodiversity
Page 1
Teacher Zone
nature.ca/education
See the associated lesson plan at
nature.ca/education/cls/lp/lpmb_e.cfm
Silk moth (Rothschildia orizaba).
Michael Branstetter © Michael Branstetter

2. What Is Biodiversity?
• The term biodiversity comes from
the words biological and diversity.
• It refers to the variety of life, and
includes all living things (plants,
animals and micro-organisms) and
their unique characteristics.
Snail.
Michael Branstetter © Michael Branstetter
Page 2
Teacher Zone
nature.ca/education

3. What Is Biodiversity?
• It can mean the variety of habitats, living communities and ecological
processes in an ecosystem.
• It can mean the diversity of genetic characteristics within a species.
• It can mean the variety of species in a given area.
Page 3
Teacher Zone
nature.ca/education

4. Why Is Biodiversity Important?
• Ecosystems depend on the combined contributions of the individual
organisms within them. The loss of any species can prevent that
ecosystem from operating the way it should.
• An ecosystem with a high level of biodiversity is more resistant to
environmental change.
Page 4
Teacher Zone
nature.ca/education

5. What Is Biodiversity?
• What does biodiversity mean to you?
• Let’s draw a mind map!
Page 5
Teacher Zone
nature.ca/education

6. Biodiversity Index
• A biodiversity index is a way of measuring biodiversity.
• Scientists use different biodiversity indices to measure diversity,
and no single one will always be appropriate for the question being
posed.
• In fact, for some conservation questions, more than one measure
may have to be used.
Page 6
Teacher Zone
nature.ca/education

7. Biodiversity Index
• Species Richness
– The total number of species in
an area (add them up!)
• Species Evenness
– How evenly the species are
represented in the area.
– E.g., Do most of the individuals
belong to one species? Weevil (Rhodobaenus sp.).
Michael Branstetter © Michael Branstetter
Page 7
Teacher Zone
nature.ca/education

8. Species Richness
• The most common type of biodiversity index is species richness, which refers to
the number of species in a particular place. This measure is commonly used
because most people have an idea what “species” means.
• It is also commonly used because species keep their genes more or less to
themselves, and to that extent have their own unique history.
Page 8
Teacher Zone
nature.ca/education

9. Simpson’s Index
• Many diversity indices have been
developed that combine different
measures of biodiversity. One is
called the Simpson’s Index.
• The Simpson’s Index includes
BOTH species richness and species
evenness in a single number.
Ocean sunfish (Mola mola).
© iStockphoto.com/Todd Winner
Page 9
Teacher Zone
nature.ca/education

10. How to Calculate
Simpson’s Index
• D is the Simpson’s Index
• n is the total number of organisms
of a particular species
• N is the total number of organisms
of all species
• ∑ means “add up”!
D =
∑ n(n - 1)
N(N - 1)
Page 10
Teacher Zone
nature.ca/education

11. Let’s Try an Example
• You have studied a specific site,
and have counted the individuals of
five different species.
• n is the total number of organisms
of a particular species.
Species A 12
Species B 3
Species C 7
Species D 4
Species E 9
n
Page 11
Teacher Zone
nature.ca/education

12. Simpson’s Index
∑ n(n - 1) = 264
D =
∑ n(n - 1)
N(N - 1)
Species A 12 11 132
Species B 3 2 6
Species C 7 6 42
Species D 4 3 12
Species E 9 8 72
∑ n(n - 1) 264
n - 1 n(n - 1)n
Page 12
Teacher Zone
nature.ca/education

13. Simpson’s Index
D =
∑ n(n - 1)
N(N - 1)
N - 1 = 34
N(N - 1) = 1190
N = total number of all individuals = 35
=
264
N(N - 1)
D = 264
1190
= 0.22184
This area would score 0.22184 on the Simpson’s Index. The scale
ranges from 0–1, with 1 representing the lowest biodiversity. Therefore,
the score for this area indicates a high level of biodiversity.
Page 13
Teacher Zone
nature.ca/education

14. Biodiversity at Sites in Honduras
The following calculations are based on sampling conducted in Honduras
by Canadian Museum of Nature research scientist Bob Anderson.
Site N N(N - 1) ∑ n(n - 1) D Species
Richness
Cerro Montecristo 2996 7 120 892 1 600 002 0.2247 61
El Pital 2050 m 233 54 056 6856 0.1268 22
El Pital 2650 m 5411 29 273 510 12 873 694 0.4398 46
Cerro Puca 311 96 410 19 126 0.1984 27
Santa Barbara 839 703 082 55 514 0.0789 44
Page 14
Teacher Zone
nature.ca/education

15. Biodiversity at Sites in Honduras
• Which site has the highest species richness?
• Which site is the most diverse according to the Simpson’s Index? (HINT: Has
the lowest D).
• Do any sites have both a low Simpson’s Index and high species richness?
Which one(s)?
Page 15
Teacher Zone
nature.ca/education

16. Biodiversity and Conservation
• Which measure—species richness
or species evenness— is more
important to conservation?
• Should we incorporate both?
Canadian Museum of Nature scientist Bob
Anderson identifying new species in the lab.
John Longino © John Longino
Page 16
Teacher Zone
nature.ca/education

17. Biodiversity and Conservation
• Why should we preserve
biodiversity?
• What is conservation?
• What does it take to conserve
areas?
• How is conservation related to
biodiversity?
Pit viper (Cerrophidion godmani).
José Monzon © José Monzon
Page 17
Teacher Zone
nature.ca/education

18. Biodiversity and Conservation
• Some species are rare in nature, or
in some areas. How is this important
to conservation studies?
• Is there a chance that scientists
might not even find the rare
species?
• Are rare species more important to
conserve than common ones?
Canadian Museum of Nature scientist
Bob Anderson conducting a biodiversity
assessment.
Michael Branstetter © Michael Branstetter
Page 18
Teacher Zone
nature.ca/education