Mean EIV

Transcription

Mean EIV

WHY ARE ELLENBERG INDICATOR VALUES
SO GOOD EXPLANATORY VARIABLES?
David Zelený
ELLENBERG INDICATOR VALUES
3
2
6
6
5
2
CALCULATION OF MEAN ELLENBERG
INDICATOR VALUES
Mycelis muralis
Moehringia trinervia
Mercurialis perennis
Lathyrus vernus
Myosotis sylvatica
Milium effusum
Melica nutans
Melampyrum pratense
Myosotis ramosissima
Lychnis viscaria
Melittis melissophyllum
EIV-reaction
1
2
3
6
7
7
4
7
5
3
2
1
2
3
1
0
1
0
1
0
1
0
1
0
0
0
1
0
1
1
0
1
1
1
0
1
0
1
1
0
0
1
0
1
0
1
0
INDICATOR VALUES
Mycelis muralis
Lathyrus vernus
Myosotis sylvatica
Milium effusum
Melica nutans
Melampyrum pratense
Lychnis viscaria
EIV-reaction
1
2
3
6
7
7
4
7
5
3
2
1
2
3
1
0
1
0
1
0
1
0
1
0
0
0
1
0
1
1
0
1
1
1
0
1
0
1
1
0
0
1
0
1
0
1
0
4.8
mean
INDICATOR VALUES
Mycelis muralis
Lathyrus vernus
Myosotis sylvatica
Milium effusum
Melica nutans
Melampyrum pratense
Lychnis viscaria
EIV-reaction
1
2
3
6
7
7
4
7
5
3
2
1
2
3
1
0
1
0
1
0
1
0
1
0
0
0
1
0
1
1
0
1
1
1
0
1
0
1
1
0
0
1
0
1
0
1
0
mean EIV:
4.8
3.9
4.6
INDICATOR VALUES
Mycelis muralis
Lathyrus vernus
Myosotis sylvatica
Milium effusum
Melica nutans
Melampyrum pratense
Lychnis viscaria
EIV-reaction
1
2
3
4
6
7
7
4
7
5
3
2
1
2
3
1
0
1
0
1
0
1
0
1
0
0
0
1
0
1
1
0
1
1
1
0
1
0
1
1
0
0
1
0
1
0
1
0
0
1
1
0
0
1
0
1
0
1
0
mean EIV:
4.8
3.9
4.6
4.6
mean EIV inherits information about
compositional similarity between plots
RANDOMIZATION OF EIVS AMONG SPECIES
3
2
6
6
5
2
RANDOMIZATION OF EIVS AMONG SPECIES
3
2
6
6
5
2
CALCULATION OF MEAN RANDOMIZED
Mycelis muralis
Lathyrus vernus
Myosotis sylvatica
Milium effusum
Melica nutans
Melampyrum pratense
Lychnis viscaria
EIV-reaction
1
2
3
4
6
7
7
4
7
5
3
2
1
2
3
1
0
1
0
1
0
1
0
1
0
0
0
1
0
1
1
0
1
1
1
0
1
0
1
1
0
0
1
0
1
0
1
0
0
1
1
0
0
1
0
1
0
1
0
Mycelis muralis
Lathyrus vernus
Myosotis sylvatica
Milium effusum
Melica nutans
Melampyrum pratense
Lychnis viscaria
EIV-reaction
1
2
3
4
7
5
4
2
3
2
7
3
7
6
1
1
0
1
0
1
0
1
0
1
0
0
0
1
0
1
1
0
1
1
1
0
1
0
1
1
0
0
1
0
1
0
1
0
0
1
1
0
0
1
0
1
0
1
0
Mycelis muralis
Lathyrus vernus
Myosotis sylvatica
Milium effusum
Melica nutans
Melampyrum pratense
Lychnis viscaria
EIV-reaction
1
2
3
4
7
7
5
3
2
6
2
7
4
3
1
1
0
1
0
1
0
1
0
1
0
0
0
1
0
1
1
0
1
1
1
0
1
0
1
1
0
0
1
0
1
0
1
0
0
1
1
0
0
1
0
1
0
1
0
Mycelis muralis
Lathyrus vernus
Myosotis sylvatica
Milium effusum
Melica nutans
Melampyrum pratense
Lychnis viscaria
EIV-reaction
1
2
3
4
6
4
3
3
5
7
7
1
7
2
2
1
0
1
0
1
0
1
0
1
0
0
0
1
0
1
1
0
1
1
1
0
1
0
1
1
0
0
1
0
1
0
1
0
0
1
1
0
0
1
0
1
0
1
0
Mycelis muralis
Lathyrus vernus
Myosotis sylvatica
Milium effusum
Melica nutans
Melampyrum pratense
Lychnis viscaria
EIV-reaction
1
2
3
4
6
4
3
3
5
7
7
1
7
2
2
1
0
1
0
1
0
1
0
1
0
0
0
1
0
1
1
0
1
1
1
0
1
0
1
1
0
0
1
0
1
0
1
0
0
1
1
0
0
1
0
1
0
1
0
5.6
4.1
3.4
3.4
Mean RANDOMIZED EIV:
THREE TYPES OF VARIABLES:
Mycelis muralis
Lathyrus vernus
Myosotis sylvatica
Milium effusum
Melica nutans
Melampyrum pratense
Lychnis viscaria
EIV-reaction
1
2
3
6
7
7
4
7
5
3
2
1
2
3
1
0
1
0
1
0
1
0
1
0
0
0
1
0
1
1
0
1
1
1
0
1
0
1
1
0
0
1
0
1
0
1
0
Mycelis muralis
Lathyrus vernus
Myosotis sylvatica
Milium effusum
Melica nutans
Melampyrum pratense
Lychnis viscaria
1
2
3
6
4
3
3
5
7
7
1
7
2
2
1
0
1
0
1
0
1
0
1
0
0
0
1
0
1
1
0
1
1
1
0
1
0
1
1
0
0
1
0
1
0
1
0
Mean RANDOMIZED EIV: 5.6 4.1 3.4
Mean EIV: 4.8 3.9 4.6
Mycelis muralis
Lathyrus vernus
Myosotis sylvatica
Milium effusum
Melica nutans
Melampyrum pratense
Lychnis viscaria
EIV-reaction
EIV-reaction
1
2
3
6
7
7
4
7
5
3
2
1
2
3
1
0
1
0
1
0
1
0
1
0
0
0
1
0
1
1
0
1
1
1
0
1
0
1
1
0
0
1
0
1
0
1
0
Random variable: 4.6 4.8 3.9
DATA USED FOR ANALYSES
Dataset 1

94 vegetation plots

forest vegetation in Vltava river
valley

measured soil pH
Dataset 2

1000 vegetation plots

forest vegetation

randomly selected from Czech
National Phytosociological
Database
INFORMATION ABOUT COMPOSITIONAL
SIMILARITY AMONG PLOTS INHERITED INTO
measured pH
calculated mean EIV for soil
reaction
r , P - results of Mantel’s test of correlation between two dissimilarity matrices
plot dissimilarity
plot 1
plot 2
plot 3
plot 2
0.33
plot 3
0.34
0.37
plot 4
0.35
0.22
0.42
plot 5
0.84
0.84
0.76
plot 4
Bray-Curtis
distance
0.82
Δ measured pH
plot 1
5.10
plot 2
4.09
plot 3
4.10
plot 2
4.09
1.01
plot 3
4.10
1.00
0.01
plot 4
4.15
0.95
0.06
0.05
plot 5
5.35
0.25
1.26
1.25
plot 4
4.15
1.20
measured pH
calculated mean EIV for soil
reaction
mean randomized EIV for soil
reaction
random variable
EIVS AS EXPLANATORY VARIABLES IN CCA
vegetation
Ecological
knowledge
(Ellenberg)
Calculated
mean EIV
explanatory
variable
Species
composition
Circularity of
reasoning
dependent
variable
COMPARISON OF MEASURED PH AND
CALCULATED EIV FOR SOIL REACTION
Mean Ellenberg reaction
7
+
++
+
+
6
+
+
5
4
+
+
+
+
+
+
++ + +
++ +
+
++
++
+
+
+
+
+
+++ + + + ++
+
+
++
+
++
+
+
++ +
+ + +
+
++
+
+
+ +
+
+
+
+
+
+
+
+
++ ++
+
+ +
+
+
+
+
++
+
+
+ +
+ +
+
3
+
+
2
+
3.5
4.0
4.5
5.0
Measured soil pH
Data: dataset 1 – river valley
CCA: COMPARISON OF MEASURED PH AND
Explained variability [%]
5
4
3
2
1
0
real pH
Ellenberg reaction
5
4
3
2
1
0
real pH
Ellenberg reaction
2.0 %
4
3
1.1%
2
2.0 %
5
1
0
real pH
Ellenberg reaction
EIVS CORRELATED WITH DCA SCORES
vegetation
Ecological
knowledge
(Ellenberg)
Calculated
mean EIV
Species
composition
Circularity of
reasoning
sample scores
on DCA axis
correlation
2
MEAN EIVS CORRELATED WITH DCA SCORES
1
Light
Temp
Cont
0
React
DCA2
Light
+++
+++
Temp
++
+++
Cont
++
+++
Moist
---
n.s.
Nutr
---
n.s.
React
---
n.s.
-1
Nutr
Tab.: significance of
Pearson’s correlation
coefficient
-2
DCA2
Moist
DCA1
-2
-1
0
DCA1
1
2
mean EIV
MEAN EIVS CORRELATED WITH DCA SCORES
sample scores on DCA axis
information
about
compositional
similarity
Significant correlations [%]
MEAN RANDOMIZED EIV CORRELATED
WITH DCA SCORES
mean EIV
mean randomized EIV
random variable
60
50
40
30
20
10
0
DCA1
DCA2
DCA3
DCA4
Mean randomized EIV



inherits information about compositional similarity among plots
carry no ecological information
more than 50% are significantly (p < 0.05) correlated with the first DCA
axis!
REGRESSION OF SPECIES RICHNESS ON MEAN
EIVS
Number of species
2
R = 0.30
p < 0.001
50
40
30
20
10
2
3
4
5
6
Mean EIV for soil reaction
information
about
compositional
similarity
REGRESSION OF SPECIES RICHNESS ON MEAN
EIVS
Significant regressions [%]
50
40
2
Number of species
Almost 40% of
significant
regressions !
R = 0.30
p < 0.001
50
40
30
20
10
30
2
3
4
5
6
Mean EIV for soil reaction
20
10
mean EIV
mean randomized EIV
random variable
0
Species richness
USE OF MEAN EIVS IN REGRESSION AND
CLASSIFICATION TREES
Moist <> 5.82266
React <> 4.19643
1
Moist <> 6.54378
Nutr <> 5.02273
14.4
7 obs
pH.H <> 4.265
SOILDPT <> 1.325
RALTRIV <> 0.6
2
3
29.7
6 obs
24
6 obs
4
39.6
5 obs
ASPSSW <> 80
RELPOS <> 0.5
9
sute <> 0.5
5
6
7
8
21.7
7 obs
26.1
7 obs
22.6
5 obs
17.7
6 obs
Dependent variable: species richness
Explanatory variables:
mean EIV
measured variables
28.1
9 obs
10
11
35.7
6 obs
41.3
7 obs
REGRESSION TREES – VARIABILITY EXPLAINED
BY MEAN RANDOMIZED EIV
20
mean randomized EIV
15
1
2
10
5
random variable
0
1
2
SUMMARY

mean Ellenberg indicator values inherits information about
compositional similarity among plots

use in CCA (as explanatory variables)



circularity of reasoning
unrealistically high explained variability
use in DCA (correlation with DCA axis)
circularity of reasoning less obvious, but still present
 unrealistically high correlation coefficients
 ~ 50 % probability of significant result even in case of no
ecological meaning

SUMMARY

correlation with species richness


unrealistically high correlation coefficients and higher probability
of significant results
use in regression trees
when mixing mean EIVs with measured variables, mean EIVs will
perform as better predictors
 unrealistically high explained variability

REGRESSION OF MEAN EIV WITH 1ST AXIS OF DCA
MODIFIED
MONTE-CARLO PERMUTATION TEST
Monte-Carlo distribution of R2
60
50
0.112
randomized values
40
30
Density
20
mean randomized EIV
10
0
60
50
0.166
40
30
20
10
0
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
2
R
R2 threshold
for p < 0.05
REGRESSION OF MEAN EIV WITH 1ST AXIS OF DCA
Significant results [%]
MODIFIED
MONTE-CARLO PERMUTATION TEST
100
80
60
40
20
0
Temp
Cont
Light
Moist
Nutr
React
mean EIV
mean randomized EIV
Data: dataset 2 – 100 plots
randomly selected from database
CONCLUSIONS

for any analysis with mean EIV: be careful with testing the
significance of relationship

for DCA: do not test the significance of correlation between mean
EIV and plot scores on DCA axes - or use modified Monte-Carlo test

for correlation with species richness or other vegetation-derived
variable: expect unrealistically high correlation coefficient and higher
probability of getting significant result

for regression and classification trees: do not mix mean EIV with
measured variables, if dependent variable is derived from species
composition (species richness, classification)
Thank you for your
attention!
ACKNOWLEDGEMENT

to Lubomír Tichý, Milan Chytrý and Ching-Feng Li from Department of Botany &
Zoology, Masaryk University, for comments and recommendations

this study was supported by long-term research plan MSM 0021622416

Mean EIV

Transcription

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