Wild plants need mycorrhizas

1
Wild plants need mycorrhizas

• Peter Johnston, Ross Beever
• Landcare Research, Tamaki
• Ian Horner
• HortResearch, Havelock North

2

• WILD
• untamed
• fierce
• rowdy
• outrageous
• uncultivated
• in their natural habitat

3
Types of mycorrhizas
Ectomycorrhiza
Arbuscular mycorrhiza
Ericoid mycorrhiza
4
Arbuscular mycorrhizas

• Glomales
• most NZ plants
• morphologically simple but genetically highly
  diverse
• some overseas evidence that mycorrhizal diversity
  determines plant diversity

5
Ericoid mycorrhizas

• Helotiales (cup fungi)
• found on in ericaceous plants
• allow these plants to grow in sites with low pH,
  high levels organic matter
• genetically highly diverse

6
Ericoid mycorrhizas

• common on introduced heather as well as native
  Epacridaceae
• Are native mycorrhizal species displaced when
  heather invades?
• What is the implication of this for
  reestablishment of native plants following
  control of heather?

7
Ectomycorrhizas
mushroom
bolete
truffle
8
Ectomycorrhizas

• Ectomycorrhizal trees in New Zealand
• beech
• tea tree

9
Giles Creek mine site
10
Giles CreekRestoration experiment established
1992by Murray Davis, Lisa Langer, Craig Ross
2001
11
Giles CreekRestoration experiment established
1992

• soils
• mine tailings
• mine tailings mixed with forest soil
• Nothofagus, totora, kahikatea, Coprosma, manuka,
  wineberry, etc

12
Nothofagus mortality
mine tailings soil
mine tailings
13
Nothofagus mortality
Phytophthora cinnamomi absent
Phytophthora cinnamomi present
mine tailings soil
mine tailings
14
Nothofagus mortality
Phytophthora cinnamomi absent
Phytophthora cinnamomi present
Why were the natural Nothofagus seedlings in the
surrounding Phytophthora-infested forests not
dying?
15
Giles creek Nothofagus mycorrhizal status
natural
planted

• natural seedlings roots 100 mycorrhizal
• planted, nursery-raised seedlings sparse
  mycorrhizal infection, 5 years after planting
• nursery-raised seedlings probably with no
  mycorrhizas at planting

16
Shadehouse experimentseedling mortality 3 months
after inoculation
53
37
13
7
0
17
Shadehouse experimentseedling mortality 3 months
after inoculation
53
37
13
7
0
Mycorrhizas provided no protection against Pc
18
Field experiment
19
Field experiment 3 months

• Fungicide mortality 0
• No fungicide mortality 50
• Mycorrhizal status has no effect

20
Messages from Giles Creek?

• Mycorrhizas do not protect Nothofagus from root
  rots?

21
Messages from Giles Creek

• Mycorrhizas do not protect Nothofagus from root
  rots?
• Or, are the kinds of mycorrhizas present just as
  important as the presence or absence of
  mycorrhizas?

22
Messages from Giles Creek

• Mycorrhizas do not protect Nothofagus from root
  rots?
• Or, are the kinds of mycorrhizas present just as
  important as the presence or absence of
  mycorrhizas?
• Are mycorrhizal species characteristic of
  undisturbed sites better at protecting their
  hosts from root rot disease?

23
Messages from Giles Creek

• Mycorrhizas do not protect Nothofagus from root
  rots?
• Or, are the kinds of mycorrhizas present just as
  important as the presence or absence of
  mycorrhizas?
• Are mycorrhizal species characteristic of
  undisturbed sites better at protecting theor
  hosts from root rot disease?
• Natural ecosystems are extremely complex

24
Messages from Giles Creek

• Mycorrhizas do not protect Nothofagus from root
  rots?
• Or, are the kinds of mycorrhizas present just as
  important as the presence or absence of
  mycorrhizas?
• Are mycorrhizal species characteristic of
  undisturbed sites better at protecting theor
  hosts from root rot disease?
• Natural ecosystems are extremely complex
• We can effectively establish seedlings by
  controlling root diseases with fungicides

25
plantations or communities?

• Trees physically dominate forests, and provide a
  physical structure to those forests, but they
  contribute a small amount of the biological
  diversity in the forest.
• The majority of the biological diversity is
  provided by the fungi and insects living in
  association with the trees.

26
plantations or communities?

• Fungal diversity
• in forests
• Nothofagus
• 5 species of trees
• gt900 species of fungi

27
plantations or communities?

• do fungi matter?
• fungi play key roles in basic ecosystem processes
  such as decomposition, nutrient flow, and
  disease, as well as providing a major food source
  to many litter and wood-inhabiting insects.
• does establishing trees bring along these other
  organisms anyway?

28
manuka sampling sites
plantations or communities?
29
manuka mushrooms
plantations or communities?

• stands lt10 years old, 25 m2 plots
• natural stands (n6)
• 4.3 species/plot
• planted stands (n13)
• 1.8 species/plot

30
manuka mushroomsTapapakanga adjacent 2.5 ha
stands
plantations or communities?
31
manuka mushroomsTapapakanga adjacent 2.5 ha
stands
plantations or communities?
Weedy, unspecialised fungi typical of disturbed
sites
32
questions from manuka mushroom sampling
plantations or communities?

• do the differences in diversity of
  ectomycorrhizal mushrooms indicate more
  widespread differences in the microbial biota as
  a whole?
• what effect might this lack of microbial
  diversity be having on manuka nutrition and
  health, and on the resilience of these trees to
  environmental stress?
• effect on other parts of the community, e.g.
  invertebrates that feed on the fungi?

33
community restoration
plantations or communities?

• be prepared to wait
• avoid plants which die
• work with natural patterns of succession
• maximise microbial diversity by adding litter,
  rotting logs, etc (but no evidence that this
  works)

34
Wild plants need mycorrhizas
as long as they are the right ones