Biodiversity Threats

Diversity Metrics Review

• Species Richness (S)
• Shannon-Wiener Index (H’)
• Evenness (E)

There are many, many more than this! Simpson’s index, Rényi entropy, Hill numbers, etc.

Species Richness (S)- total # of species

•The number of species or organisms present in an area, habitat, evolutionary
lineage

•Most commonly used measure of species diversity in communities

S = 4

Shannon-Wiener Index (H’)- richness & evenness
(sometimes called Shannon-Weaver, or often just Shannon Diversity Index)

S

12 fish
4 species

Pi = 2/12
2/12 * ln(2/12) = -0.2986

Pi = 1/12
1/12 * ln(1/12) = -0.2071

Pi = 2/12
2/12 * ln(2/12) = -0.2986

Pi = 7/12
7/12 * ln(7/12) = -0.3144

1.1187 = H’

Evenness (E or J’)

12 fish
4 species

E

1.1187 = H’

ln (S)

1.1187
ln (4)

= 0.8070

Species Richness S

= 4.00

Shannon’s Diversity H’ = 1.12

Evenness E (or J’) = 0.81

12 fish
4 species

Summary

Activity 2: Calculating Diversity

In both habitats below, calculate species richness,
Shannon-Weiner indices, and evenness.

Habitat A:
Rainforest

Habitat B: Desert

Species

Abundance

Poison Dart Frog

105

Scarlet Macaw

79

Howler Monkey

56

Piranha

231

Species

Abundance

Desert Monitor Lizard

62

Jerboa

140

Desert Sparrow

308

Saharan Silver Ant

1,241

Threats to Biodiversity

Open Ended

Briefly describe the meaning of "portfolio effects".

Portfolio Effects

Tilman 1996; Schindler et al. 2015

• The portfolio effect is the generalization that high

biological diversity stabilizes ecosystem processes and
increases the resilience of ecological systems to
perturbation including anthropogenic disturbance
(Schindler et al. 2015).

• Species-rich communities produce more temporally stable

ecosystem services because complementary or
independent species interactions perform redundant
ecosystem functions similar to a diverse investment
portfolio (Tilman 1996).

Threatened Species Worldwide

https://www.iucnredlist.org/

Open Ended

Go to www.iucnredlist.org and click on or search a species. Reply with its common name, IUCN status, and a cool fact about it (maybe find this under the "Habitat and Ecology" or "Threats" tab).

IUCN Red List Categories Species by:

1)Degree of Endangerment;
2) Pervasiveness of Threats

• According to IUCN:
“The IUCN Red List is more
than just a list of species names
and Red List Categories. It is a
compendium of information
detailing the current extinction
risk for the animal, fungus and
plant species that have been
assessed to date”.

Data

Needed

https://www.iucnredlist.org/ass
essment/sis

E.g. Verreaux's Sifaka (Propithecus verreauxi)

Multiple Choice

Which group of animals do you think the IUCN has assessed the most relative to their abundance?

• Birds

• Amphibians

• Mammals

• Fish

• They have probably been assessed equally

Summary Stats for IUCN

• To date IUCN has

assessed:
• 56% of mammals
• 41% of amphibians
• 27% of sharks and

rays

• 14% of birds
• 34% of corals
–--all values represent midpoint of
estimated range

Poll

Opinion: You are conservation scientist doing public outreach about the current biodiversity crisis. In addition to this, would it be better to present case studies about animals that have gone extinct or animals in which conservation efforts have contributed to their recovery?

• Case studies on extinct animals

• Case studies on conservation success stories

IUCN Green List of Species

Ultimate Threats to Biodiversity

HIPPO

H.I.P.P.O. Species Endangerment
• Habitat Destruction
• Invasive Species
• Pollution
• Human Population
• Overexploitation

H: Habitat Destruction

Farming, Urban Sprawl, Energy Development, & Other Human
Land Use Result in Habitat Loss, Fragmentation and Destruction

Let’s be honest, this level of modification is impressive!

Open Ended

In your own words, what do you think a human footprint is? (Hint- nothing to do with actual feet)

Human footprint is nearly

omnipresent in nature

Sanderson E. W., M. Jaiteh, M. A. Levy, K. H. Redford, A. V. Wannebo, and G. Woolmer. 2002.
The human footprint and the last of the wild. Bioscience. 52(10):891-904. (PDF file, 1.7 MB)

Misleading-
cultivated lands
considered low
impact and
depicted as green

Human Land Use Results in Habitat Loss and Fragmentation:
which ecologists generally consider the greatest proximate threat(s) to
biodiversity (Fahrig et al. 2002; Fahrig et al. 2019)

I: Invasive Species

• Invasive species are a

problem for natives

• They compete and eat

native species resulting
in species loss

• Result in biotic

homogenization; all
areas of Earth become
the same

Invasive kudzu in New York

Zebra mussels in Gull Lake

Brown tree snake in Guam

Case Study: Mosquitos in Hawaii

•Mosquitoes are not endemic to the
Hawaii; they were introduced in the
early 1800s via whaling ships

•Mosquito-carried diseases such as
avian pox and avian malaria and had
devastating impacts on native
Hawaiian forest birds--~30% loss

•Higher elevations became refugia for
many bird species as mosquitos could
not occupy highlands

Case Study Zebra Mussels

•Zebra mussels (Dreissena polymorpha) were
first introduced to in ballast water to the
Great Lakes in 1988.

•Within one year, they colonized nearly every
firm object.

•The quickly broke containment via fishing
boats and pleasure craft, and are now found
in lakes and rivers throughout the eastern
US.

•Feed on plankton and algae, turn
eutrophic lakes into oligotrophic lakes.

Quirk of Invasiveness

Endangered Invasive Species

• In Malaysia: Delicacy, that

are highly sought after for
food

• In Hawaii, they are invasive

destroying native pond fish
populations

• International priority to

save them, local initiative to
obliterate them.

P: Pollution

❖5 December, the fog thickened at

nightfall. Visibility dropped to a few
meters.

❖The following day, the sun was unable

to make much of an impression on
the thickening fog.

❖ In many parts of London, it was

impossible at night for pedestrians to
find their way home, even in familiar
districts.

❖ In the Isle of Dogs, the visibility was

at times nil. The fog there was so
thick that people could not see their
own feet!

London Fog of ‘52

❖At Heathrow Airport, visibility

remained below ten meters for
almost 48 hours.

❖ In central London, the visibility

remained below 500 meters
continuously for 114 hours below 50
meters continuously for 48 hours

London Fog of ‘52

On each day during the foggy period, the following amounts of pollutants were emitted:
✔

1,000 tons of smoke particles,

✔

2,000 tons of carbon dioxide,

✔

140 tons of hydrochloric acid and

✔

14 tons of fluorine compounds.

✔

In addition, and perhaps most

dangerously, 370 tons of sulfur
dioxide were converted into 800
tons of sulfuric acid

At London's County Hall, the

concentration of smoke in the air
increased from 0.49 milligrams per
cubic meter on 4 December to 4.46
on the 7th and 8th.
Thousands Died!!

• Led to the Air Pollution Control Act of 1955

•Fog Returns in 1962!

• Leads to the passage of the Clean Air Act of 1967

Leads to the related issue of global

climate change

• An unknown but generally agreed upon increase in current

global temperature

• An unknown but generally agreed upon raising of sea levels
• Resulted in known and traceable range shifts for at least

2-doz. Species

• Has directly contributed to the extinction of numerous species

(too many to count)

P: Human Population

…and unlikely to stabilize below 9-11 billion!

Data (Haub 2013) suggests we’ll stabilize between 9.8
and 10.2 billion—Africa and Asia slowed

O: Overexploitation

Chapters 1 & 2 Review

Multiple Choice

Conservation biology includes all of the following except

• Biology

• Economics

• Social sciences

• Applied mathematics

• None of the above

Open Ended

List one reason why biodiversity is important.

Multiple Select

Biodiversity and species richness differ based on... (select all of the correct answers- there are more than one)

• Biodiversity measures alpha diversity while species richness measures gamma diversity

• Species richness measures species abundance, while biodiversity measures differences within and between species

• Species richness accounts for differences within species, while biodiversity measures differences between species

• Biodiversity measures gamma diversity whereas species richness measures alpha diversity

Open Ended

What group of animals likely has the highest number of undescribed species?

Open Ended

In a few words, explain why the latitudinal diversity gradient is a consistent trend.

Multiple Choice

Which ethic seeks to make use of the "greatest good for the greatest number for the longest time"?

• Romantic-Transcendental Conservation Ethic

• Resource Conservation Ethic

• Evolutionary-Ecological Land Ethic