keynote lecture at grand valley state university student scholars day

Models of extinction from the Miocene to the last 40 years

Liliana M. Dávalos

Grand Valley State University12 April 2017

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Most important scientific discovery of the 18th century

Lightning as electricity? c. 1751

Conservation of mass? c. 1789

Georges Cuvier

Mass extinction! Sepkoski 1984 Paleobiology

65 million years ago looks fine © Karen Carr/Australian Museum

Until you look closely © National Geographic

The best of times Sepkoski 1984 Paleobiology

The worst of times Ceballos et al. 2015 Sci. Adv.

John James Audubon

When did it start? FAO 2012 State of the World’s Forests

NOAA

International Fertilizer Industry Association

Chauvet, 35K years ago © Stephen Alvarez/National Geographic

Here in the New World 14.5K years ago © Velizar Simeonovski/Field Museum

Halligan et al. 2016 Sci. Adv.

But 12.5K years ago

© Ron Blakey/Northern Arizona University © Illinois State Museum

The mystery of the giants

• End glaciation ~11.7K years ago

• Mastodon, ground sloths, extinct around this time

• Human hunting before that date

• What or who killed these giants?

© PBS

Mammals of the Caribbean

© Yomangani/Creative Commons © Eladio Fernandez

© Jon Flanders

More mammals of the Caribbean!

© Ghedoghedo

Rosenberger et al. 2010 Proc. R. Soc. Lond. B © Adrian Tejedor

Enter the bats of the Caribbean Dominican Republic 2014

Why did so many bats go extinct? Deglaciation!

© Adrian Tejedor

Islands of the Caribbean: The West Indies

Dávalos,& Turvey 2012 Bones, Clones, and Biomes

Trouble is we didn’t have the dates

Soto-Centeno & Steadman 2015 Sci. Rep.

A plan of action

• Hundreds of mammals• Dozens of islands • When did mammals

go extinct?• When did humans

arrive?

©Theodor de Bry/National Library of Medicine

• Cooke, Dávalos et al. 2018 Annu. Rev. Ecol. Evol. Syst.

Timing is everything Cooke, Dávalos et al. 2018 Annu. Rev. Ecol. Evol. Syst.

Cooke, Dávalos et al. 2018 Annu. Rev. Ecol. Evol. Syst.

Statistical models

• Fauna and humans overlap• Extinction by

humans possible• No fauna and human

overlap• Extinction not by

humans

How did the mammals of the Caribbean go extinct?

One size does not fit all

Larger mammals probably hunted early on

© Ghedoghedo Wilson 1989 J Field Archaeol.

Many extinction events recorded after arrival of Old World invasive competitors/predators

Turvey et al. 2012 Mamm. Biol.

© Adrian Tejedor ©Pierpont Morgan Library

Survivors are special Cooke, Dávalos et al. 2017 Annu. Rev. Ecol. Evol. Syst.

On extinction

• No single cause• Before humans

• Deglaciation• Area loss

• After humans• Hunting• Ecosystem change• Invasive species

Photo by Jon Flanders

We are here Ceballos et al. 2015 Sci. Adv.

Biodiversity is concentrated Fjeldså, Álvarez et al. 2005 Ambio

Davalos et al. 2011 Env. Sci. Tech.Forest loss from illegal

markets

Answering a question for the UN The Special Session of 2016

A matter of time

• Were illegal markets the start of deforestation?

• If not, how did deforestation begin?

Etter et al. 2008 Ann. Assoc. Am. Geogr.

Opening the frontier Denevan 1966 Geogr. Rev.

Roads and colonization projects

Brücher 1977 Geogr. Z. Schuurman 1978 Tijdschr. Econ. Soc. Ge.

Brazil

Bolivia

Peru

Colombia

Ecuador

Coca cultivation

Government-sponsored

before 1979

1990/1992

Projects

Coca cultivation

Percent forest

a b

Location of projects relates to carbon emissions Harris et al. 2012 Science

Brazil

Bolivia

Peru

Colombia

Ecuador

Coca cultivation

Government-sponsored

before 1979

1990/1992

Projects

Coca cultivation

High

Low

2014

Percent forest Probability of coca

a b c

A remarkable spatial pattern Davalos et al. 2016 Bioscience

High

Low

Probability of coca

c

Time to model

• Measure influence of the development projects• If projects set the

stage for illicit crops• Distance from

projects should decrease probability of crops

Davalos et al. 2016 Bioscience

The model helps us understand recent history Davalos et al. 2016 Bioscience

© UNODC

On forest loss

• Incomplete development has consequences

• Roads transform the landscape

• Roads are needed anyhow• Protect forests

• Parks, easements

A simple model based on fire Armenteras… Dávalos 2017 Ecol. Appl.

Thanks!