dendrochronology – analysis of annual rings in woody plants herbaceous! herb-chronology georg von...

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)