plant competition for nutrients in a phosphorus-limited ...€¦ · plant competition for nutrients...

Plant competition for nutrients in a phosphorus-limited tundra ecosystem

Emily Pickering PedersenJoseph Gaudard, Bo Elberling, Anders Michelsen

ITEX meeting 2019, Parma, Italy

Temperature

Arctic tundra ecosystems

Belowground changes

Plants

Temperature

Arctic tundra ecosystems

Belowground changes

Plants

Increased decomposition →

Increased nutrient availability

Plant species community

Ecosystem functions

Temperature

Arctic tundra ecosystems

Belowground changes

Plants

Increased decomposition →

Increased nutrient availability

Plant species community

Ecosystem functions

OrganicN

Nutrient availability and uptake

Nutrient availability and uptake

Abiotic factors↓

Precipitation

Bintanja & Andry, 2017

Nutrient availability and uptake

Geology↓

P-limitation

Bintanja & Andry, 2017

Abiotic factors↓

Precipitation

Nutrient availability and uptake

Geology↓

P-limitation

Microorganisms

Biotic interactions↓

Competition

Bintanja & Andry, 2017

Abiotic factors↓

Precipitation

Nutrient availability and uptake

1. Does increased summer precipitation alter plant N uptake?

2. Does P-limitation restrict plant N uptake?

3. What are the patterns of plant-plant and plant-microbe competition for nutrients?

Precipitation P-limitation Competition

Field location

Disko Island, Greenland69°14’ N 53°32’ W

Experimental design

PH2O

• Full factorial design• 8 mm precipitation/week• 10 g P/m2 (growing season)

Experimental design

PH2O

• Full factorial design• 8 mm precipitation/week• 10 g P/m2 (growing season)

Amino acid(glycine)

13C15N(0-10 cm depth)

Microbes

Plants

Ecosystem

Data Slides Removed

Conclusions

1. Increased precipitation reduces plant N uptake → plant stress

Conclusions

1. Increased precipitation reduces plant N uptake → plant stress

2. P accumulates, but limitation effects are unclear

Conclusions

1. Increased precipitation reduces plant N uptake → plant stress

2. P accumulates, but limitation effects are unclear

3. Plant-plant and plant-microbe competition is apparent → species community change

Thank you