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

Why does Plant Species Diversity Matter?

Boosts ecosystem productivity, community stability, and reduces invasibility.

Biodiversity provides a number of ecosystem services:Protection of water resourcesNutrient storage and recyclingContributes to climate stabilityBiological resources: food, medicine, wood products et etc.

Resource-based Niche PartitioningVS

Negative Density Dependence

Variable amounts of resources Plants compete for resources

Light, minerals, water

Resource-based Niche PartitioningVS

Negative Distance Dependence

Seedling survival is dependent on distance from conspecific individuals

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)

What are plant-soil feedbacks?

Ectomycorrhiza

Endomycorrhiza

Bridging the Divide

Resource-based Partitioning

Negative Distance Dependency

Plant-soil Feedback

The two models may work together to regulate species diversity in forests

Hypotheses

Seedlings have higher mortality in soil cultured by conspecific vs. heterospecific adults (i.e.) they experience negative PSF

Hypotheses Seedlings have greater negative PSF in low light than high

light

+

Hypotheses

Across species, there is a gradient in response to PSF

Hypotheses Negative biotic-mediated PSF

enhance light gradient partitioning

Light LevelsSe

edlin

g Pe

rform

ance

Expected results

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

Harvesting Seedlings Harvested at 4 weeks Carefully excavate seedling

Do NOT damage roots Washed

Roots for mycorrhizaeStem for phenolics

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

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

Problem Solving!

Squirrels/Chipmunks- currently on plan E Broken Equipment Tree Misidentification Contamination Weather

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