marsh food webs & oil spills: are some species more

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Marsh Food Webs & Oil Spills: Are some species more important than others? Michael J. Polito Assistant Professor Department of Oceanography and Coastal Sciences Louisiana State University Louisiana Sea Grant - Oil Spill Science Extension U.S. Fish & Wildlife Services Refuge Complex, Lacombe, LA Tuesday, August 13, 2019

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Page 1: Marsh Food Webs & Oil Spills: Are some species more

Marsh Food Webs & Oil Spills:

Are some species more important

than others?

Michael J. PolitoAssistant Professor

Department of Oceanography and Coastal Sciences

Louisiana State University

Louisiana Sea Grant - Oil Spill Science Extension

U.S. Fish & Wildlife Services Refuge Complex, Lacombe, LA

Tuesday, August 13, 2019

Page 2: Marsh Food Webs & Oil Spills: Are some species more

• We used a food web approach to predict the

role of individual species in the overall

ecosystem response to oil spills.

• Marsh fishes are expected to enhance

resilience. Water birds and snails may

destabilize marsh food webs following oil spills.

Take Home Messages

Page 3: Marsh Food Webs & Oil Spills: Are some species more

1. What is a food web?

2. Are some species in a food web more

“important” than others?

3. Are species that are “important” in the food

web also sensitive to oil?

Three Questions

Page 4: Marsh Food Webs & Oil Spills: Are some species more

Oil spills

A framework for predicting key taxa in the

ecosystem response to oil spills

Page 5: Marsh Food Webs & Oil Spills: Are some species more

1) What is a food web?

Page 6: Marsh Food Webs & Oil Spills: Are some species more

Food chains are a succession of

organisms that eat another organism

and are, in turn, eaten themselves.

1) What is a food web?

http://www.sheppardsoftware.com

Page 7: Marsh Food Webs & Oil Spills: Are some species more

A food web is the combination of all

the food chains in an ecosystem

1) What is a food web?

Page 8: Marsh Food Webs & Oil Spills: Are some species more

Food webs are tools to help us describe

complex interactions between species

1) What is a food web?

(McCann et al. 2017)

Page 9: Marsh Food Webs & Oil Spills: Are some species more

2) Measuring food web “importance”

Page 10: Marsh Food Webs & Oil Spills: Are some species more

2) Measuring food web “importance”

How connected and/or unique is a species?

(McCann et al. 2017)

Page 11: Marsh Food Webs & Oil Spills: Are some species more

2) Measuring food web “importance”

Food web importance of marsh organisms

(McCann et al. 2017)

Page 12: Marsh Food Webs & Oil Spills: Are some species more

3) Are “important” taxa sensitive to oil?

Page 13: Marsh Food Webs & Oil Spills: Are some species more

3) Are “important” taxa also sensitive to oil?

Oil sensitivity of marsh organisms

(McCann et al. 2017)

Page 14: Marsh Food Webs & Oil Spills: Are some species more

3) Are “important” taxa also sensitive to oil?

(McCann et al. 2017)

“Important” organisms can either enhance resilience or

help destabilize marsh food webs following oil spills

Page 15: Marsh Food Webs & Oil Spills: Are some species more

3) Are “important” taxa also sensitive to oil?

Water birds & omnivorous snails have high oil sensitivity and

high food web importance and thus are critically sensitive

in the response of the marsh food web to oil

Royal tern (Thalasseus maximus)Credit: Michael Polito

Marsh periwinkle

(Littoraria irrorate)Credit: Brian Roberts

Great Blue Heron (Ardea herodias)Credit: Michael Polito

Page 16: Marsh Food Webs & Oil Spills: Are some species more

3) Are “important” taxa also sensitive to oil?

Carnivorous fish from marsh creeks, ponds, and bays

should enhance resilience following an oil spill, given their

high food web importance and low oil sensitivity

Red drum (Sciaenops ocellatus)Credit: Michael Polito

Credit: Paola

Lopez-Duarte

Page 17: Marsh Food Webs & Oil Spills: Are some species more

3) Are “important” taxa also sensitive to oil?

Grass shrimp (Palaemonetes spp.) are sensitive to oil but due to

their relatively lower food web importance are less likely to

have large indirect effects for the rest of the food web

Daggerblade grass shrimp

(Palaemonetes pugio)Credit:Texas Parks and Wildlife Department

Page 18: Marsh Food Webs & Oil Spills: Are some species more

Conclusions

Page 19: Marsh Food Webs & Oil Spills: Are some species more

• We used a food web approach to predict the

role of individual species in the overall

ecosystem response to oil spills.

• Marsh fishes are expected to enhance

resilience. Water birds and snails may

destabilize marsh food webs following oil spills.

Take Home Messages

Page 20: Marsh Food Webs & Oil Spills: Are some species more

This adaptable framework is a tool that

can help prioritize oil spill research,

response, and restoration efforts.

So what?

Page 21: Marsh Food Webs & Oil Spills: Are some species more

Can be used to predict the role of taxa in

ecosystem responses to other stressors and/or in

other ecosystems

More than marshes

More than spills

Page 22: Marsh Food Webs & Oil Spills: Are some species more

This approach provides a bird’s eye view

of an ecosystem

Credit: Eddie Weeks

Page 23: Marsh Food Webs & Oil Spills: Are some species more

• Louisiana Sea Grant: Emily Maung-Douglass

• Lead Author: Mike McCann

• Co-Authors: Ken Able, Robert Christian, Joel Fodrie, Olaf Jensen, Jessica Johnson, Paola López‐Duarte, Charles Martin, Jill Olin, Brian Roberts,

Shelby Ziegler

• Costal Waters Consortium: Nancy Rabalais, Gene Turner, Linda Hooper-

Bui, Dubravko Justic

Funding: