Fisk lter comp
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Transcript of Fisk lter comp
Stoichiometry of Forest Nutrient LimitationStoichiometry of Forest Nutrient Limitation
Melany Fisk, Miami University
Bormann et al. 1977
Stoichiometry of Forest Nutrient LimitationStoichiometry of Forest Nutrient Limitation
Dynamic context:Interacting elementsResource optimization by organismsSpecies traits Disturbance and ecosystem developmentHeterogeneous landscape
Rethinking limitation Rethinking limitation What limits productivity in northern hardwood forests?
− Theory predicts N limitation
− Has N deposition induced P limitation?
− Recent syntheses predict co-limitation
Does a resource allocation framework explain patterns of limitation or co-limitation?
At what time scales can resource allocation processes operate to minimize single-element limitation?
Rethinking limitation Rethinking limitation Regional approach incorporates forest succession, soil variation
Rethinking limitation Rethinking limitation Regional approach incorporates forest succession, soil variation
parent material, succession
Rethinking limitation Rethinking limitation Regional approach incorporates forest succession, soil variation
Short-term experimental responses evaluated in context of longer-term pattern
parent material, succession
Rethinking limitation Rethinking limitation Regional approach incorporates forest succession, soil variation
Short-term experimental responses evaluated in context of longer-term pattern
N x P fertilization experiment:
13 sites30 kg N/ha/yr10 kg P/ha/yr parent material, succession
Examples of Resource Allocation Across SitesExamples of Resource Allocation Across Sites
Above vs belowground
• Total soil respiration is negatively related to N availability (Bae et al. submitted)
Belowground: N vs P
• N and P availability are coupled by phosphatase activity (Ratliff 2012)
Examples of Resource Allocation Across SitesExamples of Resource Allocation Across Sites
Above vs belowground
• Total soil respiration is negatively related to N availability (Bae et al. submitted)
Belowground: N vs P
• N and P availability are coupled by phosphatase activity (Ratliff 2012)
• Fine root allocation to acquire N vs P depends on N availability (Naples and Fisk 2010)
• P enhances C mineralization, while N depresses it (Santangelo et al, in prep)
Rastetter et al. 2013
Predictions of the multiple-element limitation modelPredictions of the multiple-element limitation model
• Allocation shifts between N and P after large-scale disturbance
• Colimitation occurs when allocation to N and P equilibrates
Rethinking limitation Rethinking limitation What limits productivity in northern hardwood forests?
Geohydrologic template
Available nutrients
Decomposer microbes mycorrhizae
Rethinking limitation Rethinking limitation What limits productivity in northern hardwood forests? Does a resource allocation framework explain patterns of
limitation or co-limitation?
Geohydrologic template
Available nutrients
Decomposer microbes mycorrhizae
Rethinking limitation Rethinking limitation What limits productivity in northern hardwood forests? Does a resource allocation framework explain patterns of
limitation or co-limitation?
Geohydrologic template
Available nutrients
Decomposer microbes mycorrhizae
Allocation feedbacks
Rethinking limitation Rethinking limitation What limits productivity in northern hardwood forests? Does a resource allocation framework explain patterns of
limitation or co-limitation?
Geohydrologic template
Available nutrients
Decomposer microbes mycorrhizae
Enzymatic feedbacks
Allocation feedbacks
Rethinking limitation Rethinking limitation What limits productivity in northern hardwood forests? Does a resource allocation framework explain patterns of
limitation or co-limitation?
Geohydrologic template
Available nutrients
Decomposer microbes mycorrhizae
Enzymatic feedbacks
Allocation feedbacks
Rethinking limitation Rethinking limitation What limits productivity in northern hardwood forests? Does a resource allocation framework explain patterns of
limitation or co-limitation?
Geohydrologic template
Available nutrients
Decomposer microbes mycorrhizae
Enzymatic feedbacks
Allocation feedbacks
Maintain consistent N:P
Rethinking limitation Rethinking limitation What limits productivity in northern hardwood forests? Does a resource allocation framework explain patterns of
limitation or co-limitation?
Geohydrologic template
Available nutrients
Decomposer microbes mycorrhizae
Enzymatic feedbacks
Allocation feedbacks
Maintain consistent N:P
Rethinking limitation Rethinking limitation What limits productivity in northern hardwood forests? Does a resource allocation framework explain patterns of
limitation or co-limitation?
Geohydrologic template
Available nutrients
Decomposer microbes mycorrhizae
Enzymatic feedbacks
Community or ecosystem level?
Allocation feedbacks
Maintain consistent N:P
Rethinking limitation Rethinking limitation What limits productivity in northern hardwood forests? Does a resource allocation framework explain patterns of
limitation or co-limitation? Is co-limitation a long-term outcome of ecosystem development?
Geohydrologic template
Available nutrients
Decomposer microbes mycorrhizae
Enzymatic feedbacks
Community or ecosystem level?
Allocation feedbacks
Maintain consistent N:P
Rethinking limitation Rethinking limitation What limits productivity in northern hardwood forests?
Does a resource allocation framework explain patterns of limitation or co-limitation?
Is co-limitation a long-term outcome of ecosystem development?
Or, is it a transient part of long-term, ultimate limitation, mediated by shifting resource allocation?
Geohydrologic template
Available nutrients
Decomposer microbes mycorrhizae
Enzymatic feedbacks
Community or ecosystem level?
Allocation feedbacks
Maintain consistent N:P