dendrochronology – analysis of annual rings in woody plants herbaceous! herb-chronology georg von...
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Dendrochronology –
Analysis of annual rings in woody
plantsherbaceous!
Herb-chronology
Georg von Arx
Overview
1. What is herb-chronology?
2. Methods in herb-chronology
3. Sample applications
- Ex. 1: Comparison of population age structure
- Ex. 2: Spatial and temporal dynamics of populations
- Ex. 3: Short-term responses of individual annual rings
- Ex. 4: Responses of annual rings to environmental gradients
- Ex. 5: Analysis of life history
4. Summary
Dendrochronolgy vs. herb-chronology
Forbs Semi-shrubs Dwarf shrubs Shrubs Trees
Long-lived; perennating tissue mostly in above-ground stems
Short-lived; perennating tissue mostly in below-ground structures
DendrochronologyHerb-chronology
Annual rings as proxies for past environmental conditions
Annual rings as proxies for past life of individual plants
Secondary xylem
Semi ring-porous
Phenology & anatomy of annual rings in perennial forbs
Primary xylem
Growing period:
1
2
3
4
Sanguisorba minor
Sanguisorba minor
1st year
2nd year
3rd year
4th year
Herb-chronology:
The analysis of annual rings in the root xylem of perennial forbs
Measures:
Number of annual rings (→ plant age)
Width of annual rings (→ growth)
Vessel parameters (→ growth, water supply)
Overview
1. What is herb-chronology?
2. Methods in herb-chronology
3. Sample applications
- Ex. 1: Comparison of population age structure
- Ex. 2: Spatial and temporal dynamics of populations
- Ex. 3: Short-term responses of individual annual rings
- Ex. 4: Responses of annual rings to environmental gradients
- Ex. 5: Analysis of life history
4. Summary
How to get annual ring data
1. Collecting roots
2. Thin cross-sections with sledge microtome
3. Staining of lignified structures (HCl/phloroglucinol)
4. Digital picture
5. On-screen analysis
Agastache urticifolia
Overview
1. What is herb-chronology?
2. Methods in herb-chronology
3. Sample applications- Ex. 1: Comparison of population age structure
- Ex. 2: Spatial and temporal dynamics of populations
- Ex. 3: Short-term responses of individual annual rings
- Ex. 4: Responses of annual rings to environmental gradients
- Ex. 5: Analysis of life history
4. Summary
Population of Bunias orientalis (Ayent, Germany, 900 m asl)
• Area: 1000 m2
• Old fallow, unmanaged• In total 200-500 individuals• Individuals are scattered
Comparison of population age structure
1995
1997
Old fallow
Num
ber
of in
divi
dual
s [%
]
Age [yrs.]
0
10
20
30
40
5038 Indv./m2
0
10
20
30
40
50
01 2 3 4 5 6 7 8 9 10
36 Indv./m2
unmanaged
De
gen
era
tin
g p
op
ula
tio
nMeadow
0
20
40
60
80
10015 Indv./m
2
0
20
40
60
80
100
1 2 3 4 5 6 7 8 9 10
127 Indv./m2
mown (1/yr) Ex
po
ne
nti
ally
gro
win
g p
op
ula
tio
n
B. orientalis
Dietz & Ullmann, Annals of Botany (1998)
Overview
1. What is herb-chronology?
2. Methods in herb-chronology
3. Sample applications- Ex. 1: Comparison of population age structure
- Ex. 2: Spatial and temporal dynamics of populations
- Ex. 3: Short-term responses of individual annual rings
- Ex. 4: Responses of annual rings to environmental gradients
- Ex. 5: Analysis of life history
4. Summary
Time
Front invasion
Diffuse invasion
Adapted from Wilson & Lee, Functional Ecology (1989)
Nu
mb
er o
f in
div
idu
als
Young cohortsIntermediate cohortsOld cohorts
Invasion patterns
Transect
Spatial population dynamics → diffuse invasion
Lythrum salicaria, Meadow (Michigan, USA)
Dietz, Biological Invasions (2002)
InvasionN
o. o
f ind
ivid
uals
Age (yrs.)
0 10 m
Shape of the populationTransect
Digitalis grandifloraAlt
er [
Jah
re]
Dietz, Biological Invasions (2002)
Ag
e [y
rs.]
Position along transect [m]
Spatial population dynamics → front invasion
Adventitious roots
Main roots
Overview
1. What is herb-chronology?
2. Methods in herb-chronology
3. Sample applications- Ex. 1: Comparison of population age structure
- Ex. 2: Spatial and temporal dynamics of populations
- Ex. 3: Short-term responses of individual annual rings
- Ex. 4: Responses of annual rings to environmental gradients
- Ex. 5: Analysis of life history
4. Summary
Mean Enso Index and deviations in mean global temperature
Mean Enso Index (Enso – El Niño/Southern Oscillation)
Mean global temperature
Data structure
USA Switzerland
Set 1 Midwest
≤ 400 m asl
8 species
Davos/Alpstein
≥ 1400 m asl
3 species
Set 2 Oregon (NW)
≥ 1200 m asl
4 species
Swiss Alps
≥ 1900 m asl
1 species
*
*
Fluctuations in growth ring width
Set 1Set 2Set 1 & 2
TemperaturePrecipitationSnow cover
USA CH
Dietz & von Arx, Ecology (2005)
Overview
1. What is herb-chronology?
2. Methods in herb-chronology
3. Sample applications- Ex. 1: Comparison of population age structure
- Ex. 2: Spatial and temporal dynamics of populations
- Ex. 3: Short-term responses of individual annual rings
- Ex. 4: Responses of annual rings to environmental gradients
- Ex. 5: Analysis of life history
4. Summary
Altitude
Environmental factors along an altitudinal gradient
Vegetation period
Temperature
Nutrients
[CO2]
Vegetation density
Temperature amplitude
Precipitation
Light
With increasing Altitude …
negative positive
Inte
nsity
of
fact
or
Wallowa Mountains, NE-Oregon, USA
Sample design
Rudbeckia occidentalis (Asteraceae) - 1200-2050 m asl - 4 altitudinal levels - 6-8 plants/level
Penstemon venustus (Scrophulariaceae) - 1150-2000 m asl - 5 altitudinal levels - 6-9 plants/level
Lupinus laxiflorus (Fabaceae) - 1400-2450 m asl - 4 altitudinal levels - 6-8 plants/level
Rudbeckia occidentalis Penstemon venustus
Lupinus laxiflorus
R. occidentalis P. venustus
L. laxiflorus
Penstemon venustus Lupinus laxiflorus Rudbeckia occidentalis vo
n A
rx e
t al
., E
colo
gy
(20
06)
Age, no. of shoots and mean ring width vs. altitude
Overview
1. What is herb-chronology?
2. Methods in herb-chronology
3. Sample applications- Ex. 1: Comparison of population age structure
- Ex. 2: Spatial and temporal dynamics of populations
- Ex. 3: Short-term responses of individual annual rings
- Ex. 4: Responses of annual rings to environmental gradients
- Ex. 5: Analysis of life history
4. Summary
Growth trajectories vs. altitude
Penstemon venustusLupinus laxiflorusRudbeckia occidentalis
von Arx et al., Ecology (2006)
Conclusions from the altitudinal gradient-study
High altitude plants grow
- older
- slower
- larger
Shifts from linear to curvilinear growth trajectories towards higher altitudes
═►More conservative and constrained life history at higher altitude
Overview
1. What is herb-chronology?
2. Methods in herb-chronology
3. Sample applications
- Ex. 1: Comparison of population age structure
- Ex. 2: Spatial and temporal dynamics of populations
- Ex. 3: Short-term responses of individual annual rings
- Ex. 4: Responses of annual rings to environmental gradients
- Ex. 5: Analysis of life history
4. Summary
Summary
Herb-chronology is the analysis of annual rings in perennial forbs
Important measures are number and width of annual rings, and diameters of xylem vessels
Herb-chronology may be valuable in the following fields (e.g.):
- Structure, spatial and temporal dynamics and comparison of populations
- Influence of extreme events on growth
- Influence of environmental gradients on life history
Acknowledgements
Hansjörg Dietz Peter J. Edwards Jake M. Alexander Regula Billeter Daniela Csencsics Silke Dietz Sabine Güsewell Moritz Kuhn Kirk A. Moloney Catherine Parks Dieter Ramseier Miriam Schädler Fritz H. Schweingruber Matthias Suter Lea Wirth
Geobotanical Institute ETH ETH Swiss National Science Foundation
Keep up-to-date with herb-chronology
http://www.plantecology.ethz.ch/spotlights/herbchronology
Roxas – Automated image analysis of annual rings in the roots of perennial forbs
Penstemon venustus
?
Mean vessel sizeVessel densityMean ring widthPlant ageetc.
Excel Worksheet
Pflanzenbilder© A. Mielnikow
www.loodusmuuseum.ee
Evaluated Species
Trifolium badium
Penstemon venustus
Bunias orientalis
Sanguisorba minor
Erinus alpinuscausses-cevennes.com
© G. von Arx
Penstemon venustus Trifolium badium
Bunias orientalisErinus alpinus
Sanguisorba minor
Trifolium badium 200 μm
Trifolium badium 200 μm
Trifolium badium 200 μm
679
98%
2379
Vessels RingsAll species
17Pseudo-vessels or -rings
95%Correctly identified
189Overall number
Vessel extraction & identification of annual rings
D = * 100R – X
R
D: deviation index
R: reference measurement
X: manual / automated measurement
D (
%)
Bo Ea Pv Sm Tb
*
D = 6.17D = 4.41
Accuracy of ring width measurements
Additional Parameters produced by ROXAS
Ring area (vs. ring width)
Average & individual vessel size
Accumulated vessel area
Accumulated vessel area per ring area
(vessel area density)
Number of vessels per xylem area
B. orientalis P. venustus E. alpinus
Average vessel size (μm2) 475 342 70
Vessel area density (%) 4.0 12.5 5.4
Summary
More objective (reproducible)
More accurate
Faster
Easier
Additional parameters
Automated analysis is …
Beauty lies in nature
The diversity of form and shape
The methuselah
The one-sided
The radiating 1
The beauty
The delicate
The radiating 2
Ontogenetisches Muster
Reaktion auf StandortfaktorenReaktion aufUmweltveränderungen
Phylogenetische Variabilität in der Jahresringentwicklung
Deutlichere Abgrenzung der Zuwachsringe
Zu
neh
men
de
Var
iab
ilit
ät d
es a
nat
om
isch
enM
ust
ers
inn
erh
alb
der
Fam
ilie
Asteraceae
Caryophyllaceae
Rosaceae
Brassicaceae
Euphorbiaceae
Apiaceae
Fabaceae
Lamiaceae
Herbchronologische Eignung im Standortsgradienten
feucht trockenBODEN
TE
MP
ER
AT
UR
KL
IMA
gleich-mässig
saisonal,kurzeWuchs-periode
hoch
Anteil von Stauden mit klaren Jahresringen in der Hauptwurzel
durchschnittlich
gering
subalpineRasen
Ruderal-standorte(ME)
MediterraneStandorte
Wald,FeuchteWiese(ME)
Trocken-rasen(ME)