fine-scale species-area relationships of the vascular flora of the southeast (usa) jason fridley,...
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Fine-scale species-area Fine-scale species-area relationships of the vascular relationships of the vascular flora of the Southeast (USA)flora of the Southeast (USA)
Jason Fridley, Robert Peet, Peter White, Joel Jason Fridley, Robert Peet, Peter White, Joel Gramling, Todd Jobe, Jessica Kaplan, Gramling, Todd Jobe, Jessica Kaplan,
Meghan McKnight, Amanda Senft, and Meghan McKnight, Amanda Senft, and David VandermastDavid Vandermast
Plant Ecology LaboratoryPlant Ecology Laboratory
University of North Carolina at Chapel HillUniversity of North Carolina at Chapel Hill
Species-area relationships Species-area relationships (SPARs)(SPARs)
• Critically important for studying Critically important for studying patterns and processes of patterns and processes of biodiversitybiodiversity
– Conservation, reserve design, extinction Conservation, reserve design, extinction ratesrates
– Spatial dependence of species richnessSpatial dependence of species richness– Relation of scale to processRelation of scale to process
Fine-scale SPARsFine-scale SPARs0.1 ha and below0.1 ha and below
• Typical form? Typical form? • Variation?Variation?• Representative of vegetation Representative of vegetation
structure?structure?– Scale dependence of local species Scale dependence of local species
richnessrichness– Patterns indicate processes?Patterns indicate processes?
• Relationship to larger species-area Relationship to larger species-area curve?curve?
Carolina Vegetation SurveyCarolina Vegetation Survey
• 0.1 ha vegetation plots across the 0.1 ha vegetation plots across the Carolinas (+ GA, TN, FL)Carolinas (+ GA, TN, FL)
• Presence of rooted vascular plant Presence of rooted vascular plant species in nested subplots at equally species in nested subplots at equally spaced areas on a logspaced areas on a log1010 axis: axis:
0.01, 0.1, 1.0, 10, 100, 1000 0.01, 0.1, 1.0, 10, 100, 1000 mm22
This study = 1454 plotsThis study = 1454 plots
Methodology: functional formMethodology: functional formGleason (exponential)Gleason (exponential)
-2 -1 0 1 2 3
Log Area (m2)
-10
10
30
50
70
90
Ric
hnes
s
Mean + s.d.
n = 1454 plots
Methodology: functional formMethodology: functional formArrhenius (power)Arrhenius (power)
-2 -1 0 1 2 3
Log Area (m2)
0.0
0.5
1.0
1.5
2.0
Log
Ric
hnes
s
Mean + s.d.
n = 1454 plots
Methodology: functional formMethodology: functional form
0.7 0.8 0.9 1.0
Coefficient of determination (R2)
0
100
200
300
400
Fre
quen
cy
Arrhenius (power) curve
Gleason (exponential) curve
0.0 0.1 0.2 0.3 0.4
020
4060
8010
012
0
Cou
nt
Arrhenius z
Histogram of log-log slope (z) of 1454 CVS plots at 6 scales
95% CIs 95% CIs
= [.214, .417]
mean = .315
median = .319
Patterns: Vegetation TypesPatterns: Vegetation Types
• Why important?Why important?– Show the signature of different Show the signature of different
processes at different scalesprocesses at different scales• small scales: plant size and density, small scales: plant size and density,
competitioncompetition• large scales: environment, species poolslarge scales: environment, species pools
• Scale dependence of species Scale dependence of species richnessrichness
-2 -1 0 1 2 3
Log Area (m2)
0.0
0.5
1.0
1.5
2.0
Log
Ric
hnes
s
Low
High
B
Low
High
A
C
D
Fine-scale SPAR functional typesFine-scale SPAR functional types
-2 -1 0 1 2 3
Log Area (m2)
0.0
0.5
1.0
1.5
2.0
Log
Ric
hnes
s
Low
High
B
Low
High
A
C
D
Type A: “plots that keep on giving”• Unusual: supply-side driven, influenced little by competitionUnusual: supply-side driven, influenced little by competition• Little spatial structure; disturbance importantLittle spatial structure; disturbance important
Type A: “plots that keep on giving”
-2 -1 0 1 2 3
Log Area (m2)
0.0
0.5
1.0
1.5
2.0
Log
Ric
hnes
s
Low
High
B
Mountain riparian communities
Low
High
A
C
D
• Unusual: supply-side driven, influenced little by competitionUnusual: supply-side driven, influenced little by competition• Little spatial structure; disturbance importantLittle spatial structure; disturbance important
(↓ competitive exclusion)
(↑ species pool)
-2 -1 0 1 2 3
Log Area (m2)
0.0
0.5
1.0
1.5
2.0
Log
Ric
hnes
s
Low
High
B
Low
High
A
C
D
Type B: high accumulation rate• Fertile site means larger plants: low individual densityFertile site means larger plants: low individual density• Large regional species pool: “sweet site”Large regional species pool: “sweet site”
-2 -1 0 1 2 3
Log Area (m2)
0.0
0.5
1.0
1.5
2.0
Log
Ric
hnes
s
Low
High
B
Montane rich cove communities
Low
High
A
C
D
(large plants: “megaforbs”)
(↑ species pool)
Type B: high accumulation rate• Fertile site means larger plants: low individual densityFertile site means larger plants: low individual density• Large regional species pool: “sweet site”Large regional species pool: “sweet site”
-2 -1 0 1 2 3
Log Area (m2)
0.0
0.5
1.0
1.5
2.0
Log
Ric
hnes
s
Low
High
B
Low
High
A
C
D
Type C: low accumulation rate• High fine richness: small plants, high densityHigh fine richness: small plants, high density• Low regional species pool, stressful siteLow regional species pool, stressful site
Type C: low accumulation rate• High fine richness: small plants, high densityHigh fine richness: small plants, high density• Low regional species pool, stressful siteLow regional species pool, stressful site
-2 -1 0 1 2 3
Log Area (m2)
0.0
0.5
1.0
1.5
2.0
Log
Ric
hnes
s
Low
High
B
Spruce-fir forests
Low
High
A
C
D
(small plants)
(↓ species pool)
-2 -1 0 1 2 3
Log Area (m2)
0.0
0.5
1.0
1.5
2.0
Log
Ric
hnes
s
Low
High
B
Low
High
A
C
D
Type D: poor sites• Low individual density: stressful conditions or large plantsLow individual density: stressful conditions or large plants• Low regional species pool, stressful siteLow regional species pool, stressful site
Type D: poor sites• Low individual density: stressful conditions or large plantsLow individual density: stressful conditions or large plants• Low regional species pool, stressful siteLow regional species pool, stressful site
-2 -1 0 1 2 3
Log Area (m2)
0.0
0.5
1.0
1.5
2.0
Log
Ric
hnes
s
Low
High
B
Xeric communities
Coastal Plain pine barrens
Xeric montane forests
Low
High
A
C
D
(very low individual density)
(↓ species pool)
-2 -1 0 1 2 3
Log Area (m2)
0.0
0.5
1.0
1.5
2.0
Log
Ric
hnes
s
Sand barrens
Dry sandy uplandWet savanna
Mesic silty upland
Rich vs. poor communitiesRich vs. poor communitiesPine woodlands and Pine woodlands and savannassavannas
Fine scales to the globeFine scales to the globe
• Incorporate richness estimates of larger Incorporate richness estimates of larger areasareas
• ““Full scale” SPARCs are rare; the few that Full scale” SPARCs are rare; the few that exist are triphasicexist are triphasic
• Where is location of inflection point?Where is location of inflection point?
-2 0 2 4 6 8 10 12 14
Log Area (m2)
12
34
5
Log
Ric
hnes
s
CVS quadrats
z = 0.25 0.1 ha
Counties, NC & SC
NC + SC
cont. US
World land (- ice)
z = 0.315
Fine scales to the globeFine scales to the globe
AcknowledgementsAcknowledgements
• 600+ participants in CVS600+ participants in CVS• T. Wentworth, M. Schafale, A. Weakley, R. BrownT. Wentworth, M. Schafale, A. Weakley, R. Brown• Financial support from USFS, NSFFinancial support from USFS, NSF
• National Parks Foundation for meeting supportNational Parks Foundation for meeting support