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Does Biological Diversity Control Ecosystem Function? Donald R. Zak School of Natural Resources & Environment University of Michigan. Human Activity and the Loss of Biological Diversity. Clearing and Fragmentation of Tropical Forests. Human Activity and the Loss of Biological Diversity. - PowerPoint PPT Presentation
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Does Biological Diversity Control Does Biological Diversity Control Ecosystem Function?Ecosystem Function?
Donald R. ZakDonald R. ZakSchool of Natural Resources & EnvironmentSchool of Natural Resources & Environment
University of MichiganUniversity of Michigan
Clearing and Fragmentation of Tropical Forests
Human Activity and the Loss of Human Activity and the Loss of Biological DiversityBiological Diversity
Human Activity and the Loss of Human Activity and the Loss of Biological DiversityBiological Diversity
Fire Suppression in Temperate GrasslandsFire Suppression in Temperate Grasslands
Human Activity and the Loss of Human Activity and the Loss of Biological DiversityBiological Diversity
Introduction of Exotic PredatorsIntroduction of Exotic Predators
Brown Tree SnakeBrown Tree Snake
Brown RatBrown Rat
Common Common MongooseMongoose
Red FoxRed Fox
Biological Diversity & Ecosystem FunctionBiological Diversity & Ecosystem Function
What happens to ecosystem function when the abundance of particular species or groups of species are reduced?
Biological Diversity & Ecosystem FunctionBiological Diversity & Ecosystem Function
Does biological diversity influence rates of ecosystem processes?
Is the relationship positive or negative?
What mathematical expression describes thisrelationship?
Research into the influence of biological diversity on ecosystem function has been motivated by three basic questions:
What are the Mechanisms Linking Plant Diversity What are the Mechanisms Linking Plant Diversity to Ecosystem Function?to Ecosystem Function?
Lack of specific mechanisms linking plant diversity & ecosystem function, especially for the influence of plant diversity on higher trophic levels.
Organic SubstratesOrganic SubstratesProduction & BiochemistryProduction & Biochemistry
Plant Diversity, Microbial Communities & Ecosystem Function:Plant Diversity, Microbial Communities & Ecosystem Function:Are There Any Links? Are There Any Links?
Soil Microbial CommunitiesSoil Microbial CommunitiesComposition & FunctionComposition & Function
Soil EnvironmentSoil EnvironmentTemperature & Water PotentialTemperature & Water Potential
Plant Community Plant Community Composition & Composition &
DiversityDiversity
Soil Microbial Community Composition Soil Microbial Community Composition & Function& Function
Substrate AvailabilitySubstrate AvailabilityAmount & BiochemicalAmount & Biochemical
CompositionComposition
Ecosystem ProcessesEcosystem ProcessesSoil C & N CyclingSoil C & N Cycling
Litter ProductionLitter ProductionAbove- & BelowgroundAbove- & Belowground
Plant Diversity & Microbial Communities Plant Diversity & Microbial Communities Conceptual ModelConceptual Model
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+
+
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Because plant species differ in their Because plant species differ in their biochemical composition, changes in diversity biochemical composition, changes in diversity should alter the production as well as range of should alter the production as well as range of compounds in detritus that limit, and thus compounds in detritus that limit, and thus control, the composition and function of control, the composition and function of heterotrophic microbial communities. heterotrophic microbial communities.
Changes in microbial community composition Changes in microbial community composition & function will alter ecosystem C and N & function will alter ecosystem C and N cycling.cycling.
Hypotheses:Hypotheses:
Cedar Creek Natural History AreaCedar Creek Natural History AreaBiodiversity ExperimentBiodiversity Experiment
Cedar Creek Natural History AreaCedar Creek Natural History AreaBiodiversity ExperimentBiodiversity Experiment
Experimental Plant Diversity Treatments - 169 mExperimental Plant Diversity Treatments - 169 m22 Plots Plots
•Random Draw of 18 Native Grasses, Random Draw of 18 Native Grasses, Forbs, and Woody PlantsForbs, and Woody Plants
•Species Richness TreatmentsSpecies Richness Treatments1, 2, 4, 8, 16 Species1, 2, 4, 8, 16 Species
•30 Replications of Each Species 30 Replications of Each Species Richness TreatmentRichness Treatment
Cedar Creek Natural History AreaCedar Creek Natural History AreaBiodiversity ExperimentBiodiversity Experiment
C4 GrassesC4 Grasses Andropogon gerardiAndropogon gerardi Buchloe dactyloidesBuchloe dactyloides Panicum virgatumPanicum virgatum Schizachyrium scopariumSchizachyrium scoparium Sorghastum nutansSorghastum nutans Sporobolus cryptandrus Sporobolus cryptandrus
C3 GrassesC3 GrassesAgropyron smithiiAgropyron smithiiElymus canadensisElymus canadensisKoeleria cristataKoeleria cristataPoa pretensisPoa pretensis
LegumesLegumesAmorpha canescens Astragalus canadensis Lespedeza capatataLupinus perennisPetalosetmum purpureum
ForbForbMonarda fistulosaMonarda fistulosa
WoodyWoodyQuercus ellipsoidalisQuercus ellipsoidalisQuercus macrocarpaQuercus macrocarpa
Cedar Creek Natural History AreaCedar Creek Natural History AreaBiodiversity ExperimentBiodiversity Experiment
Microbial Community CompositionMicrobial Community Composition- Phospholipid Fatty Acid Analysis- Phospholipid Fatty Acid Analysis
Microbial Community FunctionMicrobial Community Function- Microbial Respiration- Microbial Respiration- Gross Rates of Soil Nitrogen Cycling- Gross Rates of Soil Nitrogen Cycling
After 7 Years of Plant Growth in the Experimental Treatments, We Measured:
H-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-OHH-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-OH
H H H H H H H H H H H H H H H H H H H H H H H H H H H H
H H H H H H H H H H H H H H OH H H H H H H H H H H H H H O
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
| | | | | | | | | | | | | || | | | | | | | | | | | | | ||||
H-C-C-C-C-C-C=C-C-C=C-C-C-C-C-C-C-C-C-OHH-C-C-C-C-C-C=C-C-C=C-C-C-C-C-C-C-C-C-OH
H H H H H H H H H H H H H H H H HH H H H H H H H H H H H H H H H H
H H H H H H H H H H H H H OH H H H H H H H H H H H H O
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
| | | | | | | | | | | | || | | | | | | | | | | | | || ||
Composition of Microbial Composition of Microbial Communities Communities Lipid AnalysisLipid Analysis
Palmitic acidPalmitic acidi16:0i16:0
Linoleic acidLinoleic acid18:218:266
Fatty AcidsFatty AcidsPhospholipid Fatty AcidPhospholipid Fatty Acid
Plant and Microbial BiomassPlant and Microbial Biomass
100 300 500 700 900
10
20
30
Total Plant BiomassTotal Plant Biomassg/mg/m22
Mic
rob
ial B
iom
ass
Mic
rob
ial B
iom
ass
g C
/mg
C/m
-2-2Cedar Creek Old-Field ChronosequenceCedar Creek Old-Field Chronosequence
Zak, D.R., Zak, D.R., et al. et al. 1990. Biogeochemistry 11:111-1191990. Biogeochemistry 11:111-119
Plant Species Richness Plant Species Richness and and
Total Plant BiomassTotal Plant Biomass
0 5 10 15 20
500
1000
1500
Number of Plant SpeciesNumber of Plant Species
Tot
al P
lan
t B
iom
ass
Tot
al P
lan
t B
iom
ass
g/m
g/m
-2-2RR22 = 0.968 = 0.968P < 0.001P < 0.001
Analysis of Covariance - Adjust Means for Differences in Total Plant Biomass Among Diversity Treatments.
Assumption: Total Plant Biomass is a Surrogate for Detritus Production in Plant Communities that are Rapidly Accumulating Biomass.
Plant Species Richness Plant Species Richness and and
Microbial Community BiomassMicrobial Community Biomass
Mic
rob
ial B
iom
ass
Mic
rob
ial B
iom
ass
pm
ol P
LF
A/g
pm
ol P
LF
A/g
Number of Plant SpeciesNumber of Plant Species
1400014000
1500015000
1600016000
1700017000
1800018000
1900019000
00 55 1010 1515 2020
RR22 = 0.983 = 0.983P < 0.001P < 0.001
Lea
set
Sq
uar
e M
ean
Lea
set
Sq
uar
e M
ean
Mic
rob
ial B
iom
ass
Mic
rob
ial B
iom
ass
pm
ol P
LF
A/g
pm
ol P
LF
A/g
Number of Plant SpeciesNumber of Plant Species
1400014000
1500015000
1600016000
1700017000
1800018000
00 55 1010 1515 2020
Plant Species Richness Plant Species Richness and and
Microbial Community BiomassMicrobial Community Biomass
Least Square Means Adjusted for Differences in Plant Least Square Means Adjusted for Differences in Plant Biomass Among Diversity TreatmentsBiomass Among Diversity Treatments
00 55 1010 1515 2020
0.1840.184
0.1980.198
0.2120.212
0.2260.226
0.2400.240
Fun
gal P
LF
A:B
acte
rial
PL
FA
Fun
gal P
LF
A:B
acte
rial
PL
FA
Number of Plant SpeciesNumber of Plant Species
RR22 = 0.932 = 0.932P < 0.001P < 0.001
Plant Species Richness Plant Species Richness and and
Microbial Community CompositionMicrobial Community Composition
Number of Plant SpeciesNumber of Plant Species
Mol
e P
erce
nt
Mol
e P
erce
nt
BacteriaBacteria ActinomycetesActinomycetes FungiFungi
0.320.32
0.360.36
0.400.40a10Me16:0a10Me16:0
11 22 44 88 1616
**
**
** **
**
1.91.9
2.12.1
2.32.3
2.52.5
11 22 44 88 1616
i17:0i17:0
** ****
** **
17:017:0
0.500.50
0.540.54
0.580.58
11 22 44 88 1616 11 22 44 88 1616
a17:0a17:0
2.552.55
2.652.65
2.752.75
2.852.85
11 22 44 88 1616
cy19:0cy19:0
5.25.2
5.65.6
6.06.0
6.46.4
11 22 44 88 1616
i17:1i17:1
1.71.7
1.81.8
1.91.9
2.02.0
11 22 44 88 1616
br 15:0br 15:0
0.40.4
0.60.6
0.80.8
1.01.0
11 22 44 88 1616
**** ** ** **
**** ** ** **
10Me16:010Me16:0
4.04.0
4.24.2
4.44.4
4.64.6**
**
**4.84.8
****
****
****
**
** ** ** ** **
****
**
** **
1616
6.86.8
7.27.2
7.67.6
11 22 44 88
18:118:19c9c
1.01.0
3.03.0
5.05.0
7.07.0
9.09.0
11 22 44 88 1616
18:218:266
3.43.4
3.83.8
4.24.2
11 22 44 88 1616
16:116:15c5c
** ** ****
**
**
**
****
**
****
****
**
1.81.8
1.91.9
2.02.0
2.12.1
11 22 44 88 1616
10Me18:010Me18:0
** ** ** ** **
Plant Species Richness Plant Species Richness and and
Microbial Community CompositionMicrobial Community Composition
Astericks are Least Square Means Adjusted for Plant BiomassAstericks are Least Square Means Adjusted for Plant Biomass
Plant Species Richness Plant Species Richness and and
Microbial RespirationMicrobial Respiration
Mic
rob
ial R
esp
irat
ion
Mic
rob
ial R
esp
irat
ion
mol
CO
mol
CO
22 • g
• g
-1
-1 •• dd
-1-1
1.01.0
1.51.5
2.02.0
2.52.5
00 55 1010 1515 2020
Number of Plant SpeciesNumber of Plant Species
RR22 = 0.953 = 0.953P < 0.001P < 0.001
Number of Plant Species0 5 10 15 20
1.5
1.6
1.7
1.8
1.9
2.0
2.1
Lea
st S
qu
are
Mea
nL
east
Sq
uar
e M
ean
Mic
rob
ial R
esp
irat
ion
Mic
rob
ial R
esp
irat
ion
mol
CO
mol
CO
22 • g
• g
-1
-1 •• dd
-1-1
Plant Species Richness Plant Species Richness and and
Microbial Nitrogen TransformationsMicrobial Nitrogen Transformations
Gro
ss N
Im
mob
iliza
tion
Gro
ss N
Im
mob
iliza
tion
g N
• g
g N
• g
-1-1 •
d •
d-1-1
00 55 1010 1515 20200.70.7
0.90.9
1.11.1
1.31.3
1.51.5
Gro
ss N
Min
eral
izat
ion
Gro
ss N
Min
eral
izat
ion
g N
• g
g N
• g
-1-1 •
d •
d-1-1
00 55 1010 1515 20200.70.7
0.90.9
1.11.1
1.31.3
1.51.5
RR22 = 0.799 = 0.799P < 0.001P < 0.001
Number of Plant Species Number of Plant Species
Gross mineralization was not greater in plots with legumes, compared to plots without legumes
Plant Species Richness Plant Species Richness and and
Gross Nitrogen MineralizationGross Nitrogen Mineralization
Adjusted for Differences in Plant Biomass & Soil Organic Matter ContentAdjusted for Differences in Plant Biomass & Soil Organic Matter Content
Gro
ss N
Min
eral
izat
ion
mg
N •
g C
-1 •
d-1
150
200
250
300
0 5 10 15 20Number of Plant Species
Lea
st S
qu
are
Mea
ns
Gro
ss N
Min
eral
izat
ion
g N
• g
-1 •
d-1
0.9
1.0
1.1
1.2
0 5 10 15 20
Number of Plant Species
RR22 = 0.320 = 0.320P < 0.001P < 0.001
RR22 = 0.668 = 0.668P < 0.001P < 0.001
00 55 1010 1515 2020
55
1010
1515
Tot
al P
lant
Nitr
ogen
Tot
al P
lant
Nitr
ogen
g N
mg
N m
-2-2
Number of Plant SpeciesNumber of Plant Species
RR22 = 0.967 = 0.967P < 0.001P < 0.001
Plant Species Richness Plant Species Richness and the and the
Nitrogen Content of Plant BiomassNitrogen Content of Plant Biomass
Plant Diversity, Microbial Communities & Ecosystem Function: Plant Diversity, Microbial Communities & Ecosystem Function: Are There Any Links? Are There Any Links?
ConclusionsConclusionsPlant Species Richness Indirectly Influenced Microbial Plant Species Richness Indirectly Influenced Microbial Community Biomass, Fungal Abundance, and Community Biomass, Fungal Abundance, and Respiration by Fostering Higher Plant Productivity and Respiration by Fostering Higher Plant Productivity and Detritus Inputs to Soil.Detritus Inputs to Soil.
Plant Species Richness Directly Increased Gross N Plant Species Richness Directly Increased Gross N Mineralization and N Supply to Plants, Which Fed Mineralization and N Supply to Plants, Which Fed Forward to Further Enhance Plant Productivity.Forward to Further Enhance Plant Productivity.
Mechanisms for This Direct Effect?Mechanisms for This Direct Effect?
Research Products from McIntire-Stennis SupportResearch Products from McIntire-Stennis Support
PublicationsPublications
Zak, D.R., W.E. Holmes, D.C. White, A. Peacock & D. Zak, D.R., W.E. Holmes, D.C. White, A. Peacock & D. Tilman. 2003. Plant diversity, soil microbial Tilman. 2003. Plant diversity, soil microbial
communities and ecosystem function: are there communities and ecosystem function: are there any any links? Ecology links? Ecology in press.in press.
Grant SubmissionsGrant Submissions
Zak, D.R. Plant diversity and ecosystem function are linked by Zak, D.R. Plant diversity and ecosystem function are linked by soil microbial communities. Submitted to USDA Soils soil microbial communities. Submitted to USDA Soils & Soil Biology Program - October 23, 2002.& Soil Biology Program - October 23, 2002.