1. Plant soil feedback and
species coexistence
Interactions among pathogens,
resources, and species life histories
Dr. Neumann, Katherine Wood, Dan Marsden, Hannah Rokosz, Erica Krol, Krista Botting, Molly Crothers,
Mercedez Thill, Scylar Blaisdell, Collin Rankin, Jack Williams, Brennan Rodriguez, Keara Parker,
Allison Kintner, Savannah Warners, Scott Scripter, Laura Slavsky, Aaron Parr-Besemer, Nathan Swanny
2. Why does Plant Species Diversity
Matter?
Boosts ecosystem productivity, community stability, and reduces
invasibility.
Biodiversity provides a number of ecosystem services:
Protection of water resources
Nutrient storage and recycling
Contributes to climate stability
Biological resources: food, medicine, wood products et etc.
5. Plant-soil feedbacks (PSF) - Plants changing soil biology, chemistry and
structure in ways that alter subsequent plant survival and/or growth.
What are plant-soil feedbacks?
Pathogen damage in a Prunus
serotina (black cherry)
12. Planting Seedlings
Create 18 plots (6 per light level)
Drill 432 holes per plot
Drill 144 cores of soil from specific trees
Plant seedlings in intact cores cores go in holes in plots
7 species x 7 soil types x 3 light categories x 6 field plots x
6 seedling replicates = 7776 seedlings
13.
14. Harvesting Seedlings
Harvested at 4 weeks
Carefully excavate seedling
Do NOT damage roots
Washed
Roots for mycorrhizae
Stem for phenolics
15.
16. Phenolics
Chemical defense for plants
Kills pathogens attempting to penetrate
Hypothesized
Phenolic production increases with light availability
Phenolic production is more abundant in shade-
tolerant species
17. Phenolics Methods
Soak stem fragments in 5 mL of methanol- filtered after
12 hrs
Vortex .5 mL of extract + 1.5 mL DI water + 5 mL Folin-
Ciocalteu reagent + 2.5 mL Na2CO3
Used UV spectrophotometer- 700 nm
20. A BIG Thank You to Mark Bunce!
Thank you to Alma College for the use of its facilities and the National
Science Foundation for funding. (DEB- 1457323)
Acknowledgements
Editor's Notes
Identifying the mechanisms that maintain species richness is a central question in plant ecology.
Our goal is to provide a mechanistic based understanding to the maintenance of tree species diversity.
Two theories have been studied when it comes to species diversity.
Resource Based niche partitioning is one of the theories with species diversity
Plants have to compete for resources allowing them specific areas where they are successful.
The light map shows the different light levels in a forest, you can see that it is not uniform across the forest.
The other theory is Negative Distance Dependence.
The seedling survival depends on the distance it is from the tree. The further away the seedling is from a tree of its own species the greater chance of survival it has.
how plants change the soil
negative and positive aspect
pathogens can be species specific so if a seedling is planted in conspecific soil, it is more likely to be attacked than if it were in heterospecific soil
positive side of PSF- mycorrhizae
fungi that helps plants gather nutrients and water in return for carbohydrates from the plant
like pathogens, mycorrhizae can be species specific- conspecific = higher survival rate, heterospecific =lower
the two theories have always been tested separately, Dr. Neumann's past research (more likely to die in low than high when in own soil- especially shade intolerant) indicate that PSF connects the two theories and may better explain species coexistence
negative PSF cause negative distance dependency- seedlings don't survive near own kind
negative PSF enhance light gradient partitioning- enhance how plants respond to light
seedlings considered shade intolerant may actually survive better if soil pathogens are removed- outcompete shade tolerant plants in low light- reduce species diversity
define con- vs hetero-
3 light levels
7 species of seedling in each of the 7 species of soil (multiple trees per species)
Phenolics is the plants chemical defense
It helps to kill any pathogens that try to take over the plant
We believe that phenolics will be more abundant in shade tolerate species because they generally put more energy into chemical defense, and that in high light the seedlings will produce larger amounts of phenolics because they have more resources
Fencing- flashing- individual mesh tubes- fox urine- live traps
All except one sugar maple were actually not sugar maples
Soil from different trees can't touch- seedlings, equipment must be sterilized before planting and during transportation
Tubes of soil can dry out or flood
