Do soil communities differ between native and invasive dune grasses on

Great Lakes sand dunes?

Matthew L. Reid & Sarah M. Emery

MIPN Invasive Plant Symposium

December 10, 2015

Exotic Plants

www.inps.gov

www.iextension.entm.purdue.edu

Plant-Plant Competition

Plant-Herbivore Interactions

Plant-Mutualist Interactions

Plant Host-Parasite Interactions

Plant-Plant Competition

Plant-Herbivore Interactions

Plant-Mutualist Interactions

Plant Host-Parasite Interactions

Plant-Plant Competition

Plant-Herbivore Interactions

Plant-Mutualist Interactions

Plant Host-Parasite Interactions

Plant-Soil Feedbacks

Herbivores Parasites

Mutualists Competitors

Plant-Plant Competition

Plant-Mutualist Interactions

Plant-Herbivore Interactions

Plant Host-Parasite Interactions

Invasive Plants & Soil Interactions

• Enemy Release

– Root herbivores & parasites

• Reduced Dependence on Native Mutualists

– But may utilize native mutualists to their advantage

Belowground Interactions

Arbuscular mycorrhizal fungi Nematodes

www.ipm.iastate.edu http://mycorrhizas.info/vam.html

Nematode Functional Groups

Plant-parasite

Fungal-feeder Bacteria-feeder

Predator

www.wageningenur.nl www. plpnemweb2.ucdavis.edu/nemaplex

www.und.edu www.urbanext.illinois.edu

Enemy Release

Plant-parasite

www.wageningenur.nl

Invasive Plants Fewer plant-parasites

Arbuscular Mycorrhizal Fungi

• Nutrient uptake

• Bioprotection

Reduced Mycorrhizal Dependence

Invasive Plants Lower AMF abundance (root colonization, spores)

Study System

www.earthobservatory.nasa.gov

Aquatic-terrestrial interface

Extent 275,000 acres of dunes in MI

Dune Grasses

Ammophila breviligulata Leymus arenarius

Native Exotic

Leymus arenarius

• Biomass

• Height

• Leaf length & width

• Flower production

• Seed mass

Primary Succession

Ammophila colonizes & stabilizes dune

Ammophila dieback

Colonization by later successional species Emery. 2010. Nature Education Knowledge.

Primary Succession

Ammophila colonizes & stabilizes dune

Ammophila dieback

Colonization by later successional species Emery. 2010. Nature Education Knowledge.

Research Questions

1. Is invasion by Leymus associated with different soil communities?

2. Can invasion by Leymus be facilitated by belowground interactions with arbuscular mycorrhizal fungi and nematodes?

Research Questions

1. Is invasion by Leymus associated with different soil communities?

– Field survey

2. Can invasion by Leymus be facilitated by belowground interactions with arbuscular mycorrhizal fungi and nematodes?

– Greenhouse experiment

Research Questions

1. Is invasion by Leymus associated with different soil communities?

– Field survey

2. Can invasion by Leymus be facilitated by belowground interactions with arbuscular mycorrhizal fungi and nematodes?

– Greenhouse experiment

Hypotheses

1. Reduced mycorrhizal dependence

– Leymus will have a weaker association with AMF.

2. Enemy release

– Leymus soil will harbor fewer plant-parasitic nematodes.

2014 Field Survey

Field Survey Methods

• Vegetation survey

• 10 composite soil cores

– Nematodes and roots for AMF

• Collect tiller for nutrient analyses

20 m

1m2

Field Survey Methods

• AMF staining via vinegar-ink

• Nematode extraction via sugar flotation

• Functional group ID

• Analyses

– Mixed model ANOVA

• Fixed effect: Native (Ammophila)/Exotic (Leymus)

• Random effect: Site, Site*Species

• Response – AMF: Root colonization

• Response – Nematodes: Abundance per functional group

Results – Root Colonization

• Site and site*species interaction non-significant

• No difference in levels of root colonization

% R

oo

t C

olo

niz

atio

n

Ammophila Leymus

0

10

20

30

40

p = 0.330

Results – Total Nematodes

• Site and site*species interaction non-significant

• No difference in total nematode abundance

p = 0.5864

Ammophila Leymus 0

20

40

60

80

100

Nem

ato

de

s/1

00

mL s

an

d

Ammophila Leymus 0

10

20

30

40

50

60

Nem

ato

des/1

00m

L s

and

Results – Plant Parasites

• Site and site*species interaction non-significant

• No difference in abundance of plant-parasites

p = 0.559

Results – Predators

• Site and site*species interaction non-significant

• No difference in abundance of predators

p = 0.415

Ammophila Leymus 0

5

10

15

20

Nem

ato

des/1

00m

L s

and

Results – Bacteria-Feeders

• Site and site*species interaction non-significant

• Marginal difference in abundance

p = 0.066

Ammophila Leymus 0

10

20

30

Nem

ato

de

s/1

00

mL s

an

d

Field Survey Results

• No evidence supporting reduced mycorrhizal dependence

• No evidence supporting release from plant-parasitic nematodes

• Trend of increased abundance for bacterial-feeding nematodes – Litter quality or quantity?

– Root exudates?

– Root turnover?

Field Survey Results

• Plant Tissue Properties

Site Species % Nitrogen % Phosphorus

Green Point Dunes Leymus 0.90% 0.13%

Green Point Dunes Ammophila 1.13% 0.12%

Ludington State Park Leymus 0.92% 0.08%

Ludington State Park Ammophila 1.14% 0.11%

Meinert Park Leymus 1.66% 0.10%

Meinert Park Ammophila 1.52% 0.08%

Field Survey Results

• Soil Properties

Site Species Organic Matter Total Nitrogen

Green Point Dunes Leymus 0.52% 0.009%

Green Point Dunes Ammophila 0.67% 0.009%

Ludington State Park Leymus 0.28% 0.013%

Ludington State Park Ammophila 0.34% 0.009%

Meinert Park Leymus 0.12% 0.015%

Meinert Park Ammophila 0.17% 0.008%

Nematode Community Composition

Dorylaimoides sp. Acrobeles sp.

Trophurus sp.

2015 Field Survey

Research Questions

1. Is invasion by Leymus associated with different soil communities?

– Field survey

2. Can invasion by Leymus be facilitated by belowground interactions with arbuscular mycorrhizal fungi and nematodes?

– Greenhouse experiment

Hypotheses

1. Leymus will be less susceptible to plant-parasitic nematodes (PPN).

2. Leymus will be less dependent on arbuscular mycorrhizal fungi (AMF).

3. Leymus will have altered interactions with AMF and PPN in combination.

Methods

• Treatments:

–Native Ammophila

– Invasive Leymus

AMF

PP

N

-AMF -PPN

+AMF -PPN

+AMF +PPN

-AMF +PPN

AMF = Rhizophagus intraradices

• Obtained from INVAM at West Virginia University

PPN = Pratylenchus penetrans

• Migratory endoparasite

www.nematode.unl.edu

• Replication: 10 per treatment combination

• Data Analyses: 3-way ANOVA

Methods

• Response variables of interest

– Root colonization

– Nematode abundance

– Biomass

• Root, shoot, total

– Other traits

• Root architecture, shoot characteristics

Methods

Direct effect of AMF

p = 0.904

Direct effect of AMF

• AMF

– (P = 0.015)

• AMF*Species

– (P = 0.444)

– Leymus 30% increase

– Ammophila 41% increase

Direct effect of PPN

• PPN

– (P < 0.001)

• PPN*Species

– (P = 0.089)

– Leymus 50% decrease

– Ammophila 63% decrease

AMF enhance growth in the presence of plant-parasitic nematodes

Hypotheses

1. Leymus will be less susceptible to plant-parasitic nematodes (PPN).

– Some support

2. Leymus will be less dependent on arbuscular mycorrhizal fungi (AMF).

– Not supported

3. Leymus will have altered interactions with AMF and PPN in combination.

– Supported

Implications

• Potential competitive displacement

• Altered successional trajectories?

• Management

– Clearcast herbicide, seed head clipping

Acknowledgments

Katie Arstingstall

Brad Gottshall

Andrea Howes

Erin Kinnetz

Land Managers

Michigan DNR

Grant Traverse Regional Land Conservancy

Muskegon County Parks

Questions?