Using Soil Microbes to Enhance Restoration of Native FL Scrub. Ben Sikes University of Texas at Austin

Transcription

1 Using Soil Microbes to Enhance Restoration of Native FL Scrub Ben Sikes University of Texas at Austin

2 Talk Outline The role of soil biota in ecosystem processes and plant Current uses of soil microbes Testing the relative importance of soil microbial additions in ecosystem restoration

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4 Decomposers Root Pathogens Mycorrhizal Fungi

5 R. Campbell Soil Microbes are Everywhere and Hyperdiverse

6 George Knaphus Soil Microbes Strongly Influence Terrestrial Ecosystems Nutrient mineralization(bacteria and fungi) Decomposition Nitrogen fixation (bacteria) Soil aggregation and aeration Effects on plants

7 Plant-Soil Feedbacks are a Major Determinant of Ecosystem Processes Wardle et al Science

8 Plant-Soil Feedbacks Can Alter Plant Succession Kardol et al Ecology Letters

9 Harris 2009 Science Can Soil Microbial Additions Enhance Ecosystem Restoration?

10 André Fortrin, ULaval Using Soil Microbes in the Field Mostly used in agriculture or forestry Few examples in restoration projects or natural systems. Some success with whole soil ( black box ) approaches

11 Integrating Soil Microbes into Restoration Strategies What specific soil factors limit plants in this environment? What soil biota are normally present that may offset these limitations? Current strategies target plants directly and have direct effects on soil biota.

12 Can Soil Microbial Additions Alter Plant Establishment and Ecosystem Recovery?

13 Environmental Factors Among Sites Native reduced natives some invasion C,N Disturbed No natives C,N Δ soil Structure Pasture

14 Soil Microbial Groups in System N2 Biological Soil Crusts H2O CO2 Eukaryotic Algae and Cyanobacteria Stabilize soils Water holding Cyanos can fix N P, N Mycorrhizal Fungi Nutrient uptake Stabilize soils Water uptake Pathogen protection N,P Ascomycete/ Basidiomycete fungi Increase Decomposition Nutrient cycling Can be pathogens Can compete with plants

15 Hypotheses and Questions Does the addition of specific soil microbial communities enhance plant germination and growth? Are specific soil microbes more effective at changing soil nutrient properties? Example hypotheses: H1- Soil microbes are specialized on plant species H2- Soil microbes are specialized on local soil environmental factors H0- Soil microbes are not specialized on either but may simply pioneer decomposition processes

16 Collected soils, roots fruiting bodies across 32 sites Field Collections 4 plots/time since fire (tsf) 3 tsf (2,11,23,42*ysf) 5 plots/treatment herb vs. no herb 5 plots/treatment herb vs. no herb

17 Plant Seed Collections Collected and sorted ~32,000 seeds of nine plant species

18 Extracted DNA from whole soils and successful cultures Sequence DNA and identify Initiated cultures of algae/cyanobacteria and fungi: AMF and Asco/Basidios In the Lab

19 Pyrosequencing of Soil Microbial Communities

20 Algae and Cyanobacteria 16 Visually Unique Cultures DNA extraction and sequencing trade with UTEX Algal Culture Collection Focus on sequences differences among isolates and field data.

21 AM Fungal Trap Cultures Restart with more specific rhizosphere samples and at height of infectivity Anderson and Menges 1987

22 Asco and Basidiomycete Fungal Cultures Currently over 230 individual isolates

23 Master Fungal Database Site Type Unique Endophyte Isolates Unique FB Isolates Disturbed 8 21 (+2 Fire Lane) Pasture (NH) 14 6 Pasture (H) Reference Total ysf ysf 17 23

24 Select Fungi for Amendments 5 Fruiting Body Isolates per Site Type 8 Endophyte Isolates per Site Type

25 Direct Vs. Indirect Pathways for Different Fungi Wardle et al Science

26 Experimental Treatments Treatments 3 site types: 5 sites per type Endophytes (all w/plants) Sterile or Non-Sterile Soil +home endos + reference endos no fungi Fruiting Bodies (all nonsterile soil) Plants or No Plants + home fungi + reference fungi no fungi

27 Constructing Communities Addition Design Autoclaved soil for all sterile soil treatments 20ml of each fungal community per rep. 8 plant species per replicate Layered Additions Sterile Soil Seeds (or not) Sterile Soil Fungi Soil (Sterile or Non)

28 What is the Relative Impact on Ecosystem Processes and Native Plants?

29 Non-sterilized Sterilized Non-sterilized Sterilized All germinants (g) No Fungi To Sterilize or Not? 20 % of total germinants A. gyrans S. niveum P.feayi % 5 17% 20 "Home" fungi 0 Native Reference 76% Soil Treatment

30 Fungal Amendments Can Enhance Aristida gyrans Native Plant Germination Home fungal addition with Herbicide 3 way interactions: Site X Treatment X Fungal Origin Palafoxia feayi Likes disturbed sites Ex. Herbicide, sterilize pasture soil + ref endophytes Schizachyrium niveum Ex. With no herbicide or sterilizing, reference endophytes

31 Develop Soil Amendments as a Tool in FL Scrub Restoration

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33 Questions?

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35 Disturbed Herbicided Pasture Pasture Disturbed Herbicided Pasture Pasture Disturbed Herbicided Pasture Pasture P. feayi germinants (g) Fruiting Bodies "Home" fungi Fruiting Bodies Native Reference Fruiting Bodies No Fungi Endophytes+Sterilized "Home" fungi Endophytes+Sterilized Native Reference Endophytes+Sterilized No Fungi Endophytes "Home" fungi Endophytes Native Reference Endophytes No Fungi Control "Home" fungi Control Native Reference Control No Fungi

36 Disturbed erbicided Pasture Pasture Disturbed erbicided Pasture Pasture Disturbed erbicided Pasture Pasture S. niveum germinants (g) Fruiting Bodies "Home" fungi Endophytes+Sterilized "Home" fungi Endophytes "Home" fungi Control "Home" fungi Fruiting Bodies Native Reference Endophytes+Sterilized Native Reference Endophytes Native Reference Control Native Reference Fruiting Bodies No Fungi Endophytes+Sterilized No Fungi Endophytes No Fungi Control No Fungi

37 Dist H NH Dist H NH A.gyrans germinants Non-Sterile Sterile ABS Balds ABS Balds Home Fungi Control Home Fungi Control A. gyrans germinants dependent on soil microbes: Positive Feedbacks? Site Type

38 Expand Theory and Practice for Using Soil Microbes in Ecosystem Management Using soil microbial amendments to enhance ecosystem recovery Effects on edaphic properties depends on microbial group and origin Improving plant species management using soil microbes Germination and growth will vary by plant species, microbial group and origin

39 Buckley Lab, UQueensland North Sydney Council Soil Biota Can Mediate Plant Invasion Klironomos 2002 Nature

40 Soil Microbes as a Barometer of Ecosystem Change Soil microbes respond rapidly to environmental change Shifts in bacterial: fungal ratios or community composition Changes can cascade to higher trophic levels

41 Related Projects Using ABS Microbes 1. Finding fungi to decompose Bahiagrass litter 2. Fungal resource specialization and competition 3. Re-assembling plant and fungal communities simultaneously

42 1: Are Specific Fungi Better at Decomposition of Bahia Grass? Dominates Pasture Sites Extensive root system Enormous amounts of biomass crowd out natives and increase soil carbon

43 Litter Decomposition Experiment Shoot and root litter collected, dried and sterilized w /gamma irradition Added one of 6 fungal species 20 µm bags

44 Data

45 2. Fungal Resource Use and Competition

46 Fungal Specialization on Nutrients

47 Are Fungal Species Profiles More Related by Environment or Phylogeny? E F B C A G H D Outgroup Pasture Scrub

48 3: Community Assembly with Above and Belowground Communities

49 Metacommunity Theory A A A A B B B B B A

50 A Microcosm Community Assembly 2 Introduction Order C B A D B C D

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