A Sixth Mass Extinction? -- the IUCN Red List

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Main Points

1) The history and causes of mass extinctions -- a sixth mass extinction? -- the IUCN Red List

2) Predictors of conservation concern for mammals

3) Do conservation efforts work?

4) Q&A sesh for Test 1

Pre-reading: Mon 30 Sep = NA Weds 2 Oct = NA

Terms: mass extinction, IUCN red list

Test 1: Monday 30 September

1 Pop quiz for extra credit

Hoffman et al concluded which of the following?

A. Conservation efforts slowed, but did not stop, the loss of species of mammals

B. Conservation efforts slowed, but did not stop, the loss of species of amphibians

C. The number of mammals “red-listed” (those of conservation concern) has been increasing since the late 1990s

D. All of A-C

E. None of A-C

F. Some but not all of A-C

2 Punchline #1: we discussed two hypotheses for variation in skin color: natural selection (in which darker skin protects against UV radiation) and sexual selection (in which partners select each other based on similarity in skin tone). These hypotheses are not mutually exclusive; one could be true, both could be true, or neither could be true.

3 Punchline #2: mating and reproduction in the third chimpanzee are bizarre, especially compared to other apes. The Father-At-Home hypothesis offers an explanation for these strange behaviors/characteristics.

4 Punchline #3: in addition to mating and reproduction, H. sapiens are unusual among mammals in deliberately mutilating themselves, consuming harmful drugs, and exhibiting religion (which may be an exaptation stemming from group cohesion).

5 Over 400 Million Years of Extinction and Speciation • of the 4 billion species estimated to have evolved on Earth, 99% are currently extinct.

Stellar’s sea cow sea mink Falkland Islands wolf extinct ~1894 extinct ~1770 extinct ~1876

red wolf wild population size: ~93 Vancouver Island marmot black-footed ferret wild population size: ~250 wild population size: ~250

6 Discussion Q: given that extinction is typical, is there any reason to believe that current extinctions are atypical or otherwise “unnatural”?

Stellar’s sea cow sea mink Falkland Islands wolf extinct ~1894 extinct ~1770 extinct ~1876

red wolf wild population size: ~93 Vancouver Island marmot black-footed ferret wild population size: ~250 wild population size: ~250

7 Over 400 Million Years of Extinction and Speciation

4 5

8 Over 400 Million Years of Extinction and Speciation

Mass Extinction = a spike in extinction rates, such that a loss of >75% of species occurs within a geologically short period of time (~10,000 years).

9 Over 400 Million Years of Extinction and Speciation

10 Barnosky et al. 2011. The IUCN Red List

IUCN (International Union for the Conservation of Nature) = organization dedicated to finding solutions to environmental and species- conservation challenges.

• publishes annual “IUCN Red List” to evaluate criteria for extinction risk of species based on range size, population trends, and anthropogenic threats.

• purpose of red list is to direct conservation action for Earth’s biodiversity.

11 The IUCN Red List

12 Discussion Q: what traits of mammals do you think predict extinction risk of mammals?

13 Biological Predictors of Extinction

14 Davidson et al. 2009. non-volant mammals bats 2 2 m iduals/k ividuals / km ividuals Indiv nd i

Log mass Brown. 1995. log10 mass 2 individuals / km / individuals

black rhino

log10 mass Brown. 1995.

black-footed ferret Vancouver island marmot A Brief Diversion: Distinguishing Marmots from Ferrets

21 The IUCN Red List

IUCN ranking criteria

1) Increased rate of decline

22 The IUCN Red List

IUCN ranking criteria

1) Increased rate of decline 2) Small geographic range and declining

23 The IUCN Red List

IUCN ranking criteria

1) Increased rate of decline 2) Small geographic range and declining 3) Small population size and declining

24 The IUCN Red List

IUCN ranking criteria

1) Increased rate of decline 2) Small geographic range and declining 3) Small population size and declining 4) Very small population size (VU = 1000; EN = 250; CR = 50)

25 Do Conservation Efforts Work?

26 Hoffman et al. 2010. Do Conservation Efforts Work?

Proportion RLI change

27 baiji (EN to CR) hirola (EN to CR) humpback whale (VU to LC) Do Conservation Efforts Work?

observed change in Red List Index expected change in Red List Index if species with improved status had undergone no change 28 Hoffman et al. 2010. “I can’t think about that right now. If I do I’ll go crazy. I’ll think about it tomorrow.”

-- S. O’Hara