pattern of spread of zebra mussels in minnesota · michael mccartney’s talk after the break!...

Pattern of spread of zebra mussels in Minnesota

Sophie Mallez & Michael McCartneysmallez@umn.edu/mmccartn@umn.edu

October 17th, 2016

The zebra mussel invasion

• Native to the Ponto-Caspian region

• Introduced in Europe (1800) and North America (1985)

• Introduced in Minnesota in 1989• Spread through the Mississippi and St Croix rivers• First inland lake infested in 2003• New infestations occurred yearly but < 2 % lakes infested

The zebra mussel invasion

• Native to the Ponto-Caspian region

• Introduced in Europe (1800) and North America (1985)

• Introduced in Minnesota in 1989• Spread through the Mississippi and St Croix rivers• First inland lake infested in 2003• New infestations occurred yearly but < 2 % lakes infested

Great benefits of targeted prevention

Pattern of spread – Key step

Preventing = Understanding the pattern of spread

Pattern of spread – Key step

Preventing = Understanding the pattern of spread

Dispersal

Pattern of spread – Key step

Preventing = Understanding the pattern of spread

Dispersal

DiffusionStepping-stone

Long-distance dispersal

Stratified dispersal

Pattern of spread – Key step

Preventing = Understanding the pattern of spread

Dispersal

DiffusionStepping-stone

Long-distance dispersal

Stratified dispersal

Important mechanism for zebra mussel spread

Overland

Pattern of spread – Key step

Preventing = Understanding the pattern of spread

Dispersal

DiffusionStepping-stone

Long-distance dispersal

Stratified dispersal

Small spatial scales?

Multiple independent events of introduction from distant lakes or local spread from infested lakes nearby?

Pattern of spread – Key step

Preventing = Understanding the pattern of spread

Dispersal

DiffusionStepping-stone

Long-distance dispersal

Stratified dispersal

Small spatial scales?

Identifying the vectors involvedWhat to target for limiting the spread?

Pattern of spread – Key step

Preventing = Understanding the pattern of spread

Dispersal

DiffusionStepping-stone

Long-distance dispersal

Stratified dispersal

Study of clustered invasions

Small spatial scales?

Samples & Tools

• Sampling throughout Minnesota mostly• 59 sites - 35 water bodies – 1747 individuals

Samples & Tools

• Sampling throughout Minnesota mostly• 59 sites - 35 water bodies – 1747 individuals

Samples & Tools

• Sampling throughout Minnesota mostly• 59 sites - 35 water bodies – 1747 individuals

• Genotyping of 9 microsatellite markers• Obtained from the literature • Optimized for this study

Samples & Tools

• Sampling throughout Minnesota mostly• 59 sites - 35 water bodies – 1747 individuals

• Genotyping of 9 microsatellite markers• Obtained from the literature • Optimized for this study

• Population genetics analyses• Analysis of diversity• Analysis of genetic structure/clustering• Approximate Bayesian Computation

Analysis of genetic diversity

Analysis of genetic diversity

*Mille Lacs Lake Prior Lake 8 lakes in Alexandria area

Moderate founder effects due to bottlenecks

Analysis of genetic diversity

Broad pattern:Large number of mussels and/or larvae cause infestations

Moderate founder effects due to bottlenecks

Analysis of genetic structure/clustering

Well-defined clusters distinguish important lake infestations

K = 2

K = 3

K = 4

K = 5

K = 6

K = 7

K = 8

Mille Lacs Prior Alexandria area Brainerd area

Analysis of genetic structure/clustering

Prior Lake

Mille Lacs Lake

Analysis of genetic structure/clustering

Prior Lake

Mille Lacs Lake

Analysis of genetic structure/clustering

Michael McCartney’s talk after the break!

Analysis of genetic structure/clustering

Brainerd-area lakes

+ Mississippi River

Analysis of genetic structure/clustering

Brainerd-area lakes

+ Mississippi River

K = 1

K = 2

K = 3

K = 4

Analysis of genetic structure/clustering

Brainerd-area lakes

+ Mississippi River

K = 1

K = 2

K = 3

K = 4

Local spread = the main process

occurring in this area

Alexandria-area lakes

Analysis of genetic structure/clustering

Alexandria-area lakes

Analysis of genetic structure/clustering

Alexandria-area lakes

Analysis of genetic structure/clustering

Analysis of genetic structure/clustering

Alexandria-area lakes

Infested lake

Analysis of genetic structure/clustering

Alexandria-area lakes

Approximate Bayesian Computation

CarlosIrene

Darling

Mary

Analysis of invasion models

• Approximate Bayesian Computation• Comparison of scenarios of invasion• Selection of the most likely one based on probabilities

Analysis of invasion models

• Approximate Bayesian Computation• Comparison of scenarios of invasion• Selection of the most likely one based on probabilities

Carlos IreneDarling Mary2009 20112010 2013

Carlos Darling

Carlos Darling

Analysis of invasion models

• Approximate Bayesian Computation• Comparison of scenarios of invasion• Selection of the most likely one based on probabilities

Carlos Irene

Irene independent

Darling Irene

Carlos IreneDarling Mary2009 20112010 2013

Carlos Darling

Carlos Darling

Analysis of invasion models

• Approximate Bayesian Computation• Comparison of scenarios of invasion• Selection of the most likely one based on probabilities

Carlos

Mary independent

MaryDarlingIrene

Carlos

Darling

Irene

Irene MaryMary

Carlos IreneDarling Mary2009 20112010 2013

Carlos Darling

Carlos Darling

Irene independent

Analysis of invasion models

• Approximate Bayesian Computation• Comparison of scenarios of invasion• Selection of the most likely one based on probabilities

Carlos

Mary independent

MaryDarlingIrene

Carlos

Darling

Irene

Irene MaryMary

Carlos IreneDarling Mary2009 20112010 2013

Carlos Darling

Carlos Darling

Irene independent

24 scenarios to compare!

DarlingMary

Carlos

Irene

Analysis of invasion models

Scenario with the highest probability

Prob. = 52 %Carlos

Darling independent

Mary independent

Irene

DarlingMary

Carlos

Irene

Analysis of invasion models

Scenario with the highest probability

Local spread – Stepping-stone pattern

Carlos Irene

Prob. = 52 %

Darling independent

Mary independent

DarlingMary

Carlos

Irene

Analysis of invasion models

Scenario with the highest probability

Independent events of introduction

Carlos Irene

Prob. = 52 %

Darling independent

Mary independent

Results summary

• High genetic diversity: Infestations are founded by many individuals

• If veligers in residual water are the vector—multiple introductions• Vectors that transmit juveniles or adults—docks, lifts, resident

boats—can introduce large #s of mussels per transport event

Results summary

• High genetic diversity: Infestations are founded by many individuals

• If veligers in residual water are the vector—multiple introductions• Vectors that transmit juveniles or adults—docks, lifts, resident

boats—can introduce large #s of mussels per transport event

• Clustered invasion• Local spread = predominant at small spatial scales

Brainerd area

Alexandria areaLocal spread + Independent

events of introduction

Different vectors involved?Boats vs. Lifts, docks…

• UMN: Grace Van Susteren, Sarah Peterson, Maxwell Kleinhausand Melody Truong for sampling and lab support

• NPS: Byron Karns and Michelle Prosser for field/sampling support and advice

• MnDNR: Daniel Swanson and Richard Rezanka for field/sampling support and advice

• Clear Water Fund, ENRTF for funding

For more information on MAISRC, please visit:http://www.maisrc.umn.edu

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