Do soil communities differ between native and invasive dune grasses on Great Lakes sand dunes?

Transcription

1 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

2 Exotic Plants

3 Plant Host-Parasite Interactions Plant-Herbivore Interactions Plant-Plant Competition Plant-Mutualist Interactions

4 Plant Host-Parasite Interactions Plant-Herbivore Interactions Plant-Plant Competition Plant-Mutualist Interactions

5 Plant Host-Parasite Interactions Plant-Herbivore Interactions Plant-Plant Competition Plant-Mutualist Interactions Plant-Soil Feedbacks

6 Plant Host-Parasite Interactions Plant-Herbivore Interactions Plant-Plant Competition Plant-Mutualist Interactions Mutualists Herbivores Parasites Competitors

7 Invasive Plants & Soil Interactions Enemy Release Root herbivores & parasites Reduced Dependence on Native Mutualists But may utilize native mutualists to their advantage

8 Belowground Interactions Arbuscular mycorrhizal fungi Nematodes

9 Nematode Functional Groups www. plpnemweb2.ucdavis.edu/nemaplex Plant-parasite Bacteria-feeder Predator Fungal-feeder

10 Enemy Release Plant-parasite Invasive Plants Fewer plant-parasites

11 Arbuscular Mycorrhizal Fungi Nutrient uptake Bioprotection

12 Reduced Mycorrhizal Dependence Invasive Plants Lower AMF abundance (root colonization, spores)

13 Study System Aquatic-terrestrial interface Extent 275,000 acres of dunes in MI

14 Dune Grasses Ammophila breviligulata Leymus arenarius Native Exotic

15 Leymus arenarius Biomass Height Leaf length & width Flower production Seed mass

16 Primary Succession Ammophila colonizes & stabilizes dune Ammophila dieback Emery Nature Education Knowledge. Colonization by later successional species

17 Primary Succession Ammophila colonizes & stabilizes dune Ammophila dieback Emery Nature Education Knowledge. Colonization by later successional species

18 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?

19 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

20 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

21 Hypotheses 1. Reduced mycorrhizal dependence Leymus will have a weaker association with AMF. 2. Enemy release Leymus soil will harbor fewer plant-parasitic nematodes.

22 2014 Field Survey

23 Field Survey Methods 1m 2 20 m Vegetation survey 10 composite soil cores Nematodes and roots for AMF Collect tiller for nutrient analyses

24 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

25 % Root Colonization Results Root Colonization Site and site*species interaction non-significant p = No difference in levels of root colonization Ammophila Leymus

26 Nematodes/100mL sand Results Total Nematodes Site and site*species interaction nonsignificant No difference in total nematode abundance p = Ammophila Leymus

27 Nematodes/100mL sand Results Plant Parasites Site and site*species interaction nonsignificant p = No difference in abundance of plant-parasites Ammophila Leymus

28 Nematodes/100mL sand Results Predators Site and site*species interaction nonsignificant No difference in abundance of predators p = Ammophila Leymus

29 Nematodes/100mL sand Results Bacteria-Feeders Site and site*species interaction nonsignificant Marginal difference in abundance p = Ammophila Leymus

30 Field Survey Results No evidence supporting reduced mycorrhizal dependence No evidence supporting release from plantparasitic nematodes Trend of increased abundance for bacterialfeeding nematodes Litter quality or quantity? Root exudates? Root turnover?

31 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%

32 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%

33 Nematode Community Composition Dorylaimoides sp. Acrobeles sp. Trophurus sp.

34 2015 Field Survey

35 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

36 Hypotheses 1. Leymus will be less susceptible to plantparasitic 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.

37 PPN Methods Treatments: Native Ammophila Invasive Leymus AMF -AMF +AMF -PPN -PPN -AMF +PPN +AMF +PPN

38 AMF = Rhizophagus intraradices Obtained from INVAM at West Virginia University

39 PPN = Pratylenchus penetrans Migratory endoparasite

40 Methods Replication: 10 per treatment combination Data Analyses: 3-way ANOVA

41 Methods Response variables of interest Root colonization Nematode abundance Biomass Root, shoot, total Other traits Root architecture, shoot characteristics

42 Direct effect of AMF p = 0.904

43 Direct effect of AMF AMF (P = 0.015) AMF*Species (P = 0.444) Leymus 30% increase Ammophila 41% increase

44 Direct effect of PPN PPN (P < 0.001) PPN*Species (P = 0.089) Leymus 50% decrease Ammophila 63% decrease

45 AMF enhance growth in the presence of plant-parasitic nematodes

46 Hypotheses 1. Leymus will be less susceptible to plantparasitic 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

47 Implications Potential competitive displacement Altered successional trajectories? Management Clearcast herbicide, seed head clipping

48 Acknowledgments Katie Arstingstall Brad Gottshall Andrea Howes Erin Kinnetz Land Managers Michigan DNR Grant Traverse Regional Land Conservancy Muskegon County Parks

49 Questions?