Town and Country Reptiles:How Animals Respond to a Changing Environment

Susannah S. FrenchDepartment of Biology & the Ecology Center

Why

Reptiles?

• Prevalent in different environments

• Same hormones and functions

• Natural variation in populations

• Territorial

Energetic Trade-offs

Imm

un

ity

Reproduction

Energetic Trade-offs

How do scientists

monitor impact?

Traditional methods:

• Censuses

• Demographic

information

• Behavioral data

Physiological

Approach

• Fast detection

• Provides mechanisms

& thus an understanding of

HOW perturbations affect

individuals

• Provide insight for

management

How do we measure stress?

• Hormones!

• Cortisol (& metabolites)

• Same hormones in humans & reptiles

Cortisol /

Corticosterone

Energy mobilizing hormones

• increases during

predictable events that

require energy

• increases during stressful unpredictable events

Thus need to also make functional

assessments

Why the Galapagos?

• Increase in population and increase in ecotourism

• Isolated animal populations

• Varying frequency & intensity of ecotourism

among populations

People on the Galapagos

People on the Galapagos

Why marine iguanas?

• Studied for ~20 years

• Not endangered

• Seasonal breeders

• Long-lived

• Easily sampled

What we are measuring…

• Body condition / ectoparasite prevalence

What we are measuring…

• Body condition / ectoparasite prevalence

• Female clutch size

What we are measuring…

• Body condition / ectoparasite prevalence

• Female clutch size

• Cutaneous wound healing

More than 50% of animals have a wound or a scar

What we are measuring…

• Body condition / ectoparasite prevalence

• Female clutch size

• Cutaneous would healing

• Stress response

What we are measuring…

• Body condition / ectoparasite prevalence

• Female clutch size

• Cutaneous would healing

• Stress response

• Immune measures

Stress responsiveness,

immunological &

reproductive measures

Pairs of sites in close

proximity on 3 islands

Tourist

Undisturbed

Increase stress response at tourist sites

Decrease in wound

healing at tourist sites

Increase in tourism leads to a decrease

in bactericidal ability

Decrease of clutch sizes at tourist

sites

Decrease of clutch sizes at tourist

sites

20

25

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50

2-F

eb

3-F

eb

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eb

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eb

Tem

pe

ratu

re °

C

iguana

oceano

aire

A quick example of ocean activity data

20

25

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40

45

50

0:0

0

6:0

0

12:0

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0

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Tem

pera

ture

°C

2 Februaryiguana

oceano

aire

10:19

12:2910:59

11:49

A quick example of ocean activity data

•Ecotourism

•Altered endocrine responses

•Altered immunity and reproduction

•But what about the population?

Uta stansburiana:

• Highly prolific

• Territorial

• Shorter-lived (1-2 years)

Stress responsiveness,

immunological &

reproductive measures

8 research sites

Rural

Urban

Indicator Urban Rural

Stress increase decrease

Immunity decrease increase

Reproductionincrease decrease

Stress

Summary

Do physiological changes translate

to the population?

• Determine what populations are most

susceptible

• Determine what makes populations more

susceptible

Applications of our work

AcknowledgementsField & Lab Assistance:

Geoffrey Smith

Lori Neuman-Lee

Andrew Durso

Gareth Hopkins

Austin Spence

Marilize Van der Walt

Heather Skinner

Tyler Hansen

Sydney Greenfield

Herp group @ USU

Funding Sources: UAES

USU VPR

National Science Foundation

Edmund Brodie Jr.

Alan Savitzky

David Koons

Bobby Fokidis

Gregory Demas

Dale DeNardo

Michael Angilletta

Peter Zani

Erick Yucailla

Nick Kiriazis

Trevor Brown

Desmond Brown

Questions?