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 Host-Parasite Plant-Plant Interactions Competition
Plant-Herbivore Interactions Plant-Mutualist Interactions Plant Host-Parasite Plant-Plant Interactions Competition
Plant-Herbivore Interactions Plant-Mutualist Interactions Plant Host-Parasite Plant-Plant Interactions Competition
Plant-Herbivore Interactions Plant-Mutualist Interactions
Plant-Soil Feedbacks Plant Host-Parasite Plant-Plant Interactions Competition
Plant-Herbivore Interactions Plant-Mutualist Interactions
Mutualists Competitors
Herbivores Parasites 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
http://mycorrhizas.info/vam.html www.ipm.iastate.edu Nematode Functional Groups
www.wageningenur.nl www. plpnemweb2.ucdavis.edu/nemaplex
Plant-parasite Predator Bacteria-feeder Fungal-feeder
www.und.edu www.urbanext.illinois.edu Enemy Release
www.wageningenur.nl
Invasive Plants Fewer plant-parasites Plant-parasite Arbuscular Mycorrhizal Fungi
• Nutrient uptake • Bioprotection Reduced Mycorrhizal Dependence
Invasive Plants Lower AMF abundance (root colonization, spores) Study System
Aquatic-terrestrial interface
www.earthobservatory.nasa.gov
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 Emery. 2010. Nature Education Knowledge. successional species Primary Succession
Ammophila colonizes & stabilizes dune
Ammophila dieback
Colonization by later Emery. 2010. Nature Education Knowledge. successional species 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
1m2 20 m
• Vegetation survey • 10 composite soil cores – Nematodes and roots for AMF • Collect tiller for nutrient analyses
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 40 site*species
interaction 30 p = 0.330 non-significant • No difference 20 in levels of root 10
colonization ColonizationRoot %
0 Ammophila Leymus Results – Total Nematodes
• Site and 100
site*species p = 0.5864 80 interaction non-
significant 60 • No difference in total nematode 40
abundance 20 Nematodes/100mL sand Nematodes/100mL 0 Ammophila Leymus Results – Plant Parasites
• Site and
60 site*species interaction non- 50 p = 0.559 significant 40
• No difference in 30 abundance of plant-parasites 20
Nematodes/100mL sand Nematodes/100mL 10
0 Ammophila Leymus Results – Predators
• Site and 20 site*species p = 0.415 interaction non- 15 significant
• No difference in 10 abundance of
predators 5 Nematodes/100mL sand Nematodes/100mL
0 Ammophila Leymus Results – Bacteria-Feeders
• Site and site*species 30 p = 0.066
interaction non- sand
significant 20 • Marginal difference in 10
abundance Nematodes/100mL 0 Ammophila Leymus 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 AMF – Invasive Leymus -AMF +AMF
-PPN -PPN PPN -AMF +AMF +PPN +PPN AMF = Rhizophagus intraradices
• Obtained from INVAM at West Virginia University PPN = Pratylenchus penetrans
• Migratory endoparasite
www.nematode.unl.edu Methods
• 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 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?