PDF - LIFE-Baltcoast

University
of Hamburg
LIFE BaltCoast – Final Seminar
Ecology of Apium repens
Germination and survival of Apium repens in „coastal
conditions“
Antonia Wanner, Sandra Burmeier, Jan Schwerdtfeger & Kai Jensen
WG Applied Plant Ecology, Biocentre Klein Flottbek, University of Hamburg
[email protected]
[email protected]
Department
of Biology
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Outline

Apium repens: Who is it?
• Biology
• Distribution and threat

Guiding questions
Habitat requirements
• Hydrology
• Soil conditions
Experimental ecology
• Interspecific competition
• Field: Herbivory and vegetation gaps
• Germination, dormancy, dispersal
(Re)Introduction: Establishment of new populations
• Experimental design
• Establishment success
Conclusions
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Einleitung
Ökologie
Habitat
Experimental
Standortecology
Ansiedlung
(Re)Introduction
Conclusions
Ausblick
Apium repens: Who is it?

Characteristics
• Perennial, evergreen Umbellifer
• 10-30 cm height
• Reproduction by seeds and runners
Threat and protection status
• Has
always been rare
In Schleswig-Holstein
• Pronounced
decline
in the last decades
only one
recent
• Listed in Annex II & IV of the Habitats
population!
Directive,
Red Lists (D and SH: 1 =
threatened
withinextinction),
(Status
2006) legally
protected in D
Range
• in Europe from GB to Portugal
• Germany: 4 main areas of distribution
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Guiding questions

Is Apium repens rare due to
• …specific habitat requirements?
• …low competitive ability?
• …narrow regeneration niche?
• …dispersal limitation?

How can we protect present populations?
(How) can we establish new populations?
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Site conditions: Hydrology, soil parameters

Hydrology: Groundwater levels
• Fehmarn, Sundwiesen
• Groundwater logger, 1 year
Soil parameters
• 20 populations in Northern Germany
• pH, carbon content, macro nutrients
Ellenberg Indicator values
• 85 vegetation relevés from Northern Germany
• Weighted means of the vegetation vs. Apium
repens
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Site conditions: groundwater levels

Strong fluctuations
during the year
0.3
0.2
Several weeks of
submergence in spring
Summer water level: 40
to 50 cm below ground
0.1
Groundwater level (m)

0.0
-0.1
-0.2
-0.3
-0.4
-0.5
Burmeier & Jensen (2009)
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
06-06
05-06
04-06
03-06
02-06
01-06
12-05
11-05
10-05
09-05
08-05
07-05
-0.6
Date
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Site conditions: Soil parameters

pH-value ± neutral
Narrow C/N-ratio
Wide range of carbon and nutrient contents
Burmeier & Jensen (2009)
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions

L- and N- values of
Apium high, higher than
that of the vegetation
High range of F- and Nvalues of the vegetation
Indicator value
Weighted mean Ellenberg value
Site conditions: Ellenberg Indicator values
10
8
*
6
* * *
*
4
*
2
*
0
Burmeier & Jensen (2009)
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
L
T
K
F
R
Parameter
LIFE BaltCoast – Final Seminar
N
S
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Site conditions: Summary
•
Edaphic requirements rather unspecific
•
Characteristic factors:
– Disturbance (Grazing, mowing, wave
action, camping….)
– Fluctuating water levels
Æ Habitat requirements not very specific
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Experimental ecology: competition, establishment

Apium repens under „coastal conditions“?
Flooding and salinity tolerance
• Water regime: fresh vs. brackish water (10‰)
• Submergence: 0, 2, 4, 8, 2x2 weeks
Disturbance and interspecific competition
• Disturbance regime: mowing vs. control
• Competition with Ranunculus repens
Establishment in the field
• Transplant experiment on the island Fehmarn
• Vegetation gaps (yes/no) and herbivory
(yes/no)
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Experimental ecology: Flooding tolerance
• Submergence by freshwater is
tolerated (but: loss of vitality!)
• Submergence by saltwater
(10‰) leads to death
Burmeier & Jensen (2009)
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Experimental ecology: disturbance and competition

Competition by R. repens
and disturbance by
mowing reduce biomass
of A. repens
No interaction between
factors
Burmeier & Jensen (2009)
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Experimental ecology: Establishment in the field
Grazing
no
yes
Closed vegetation canopy
yes
no
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
n = 25
n = 25
n = 25
n = 25
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Experimental ecology: Establishment in the field

No significant differences
between the groups, but
100
Initially higher mortality
of grazed plants
Later, higher mortality of
ungrazed plants
Cumulative survival (%)

80
60
exposed/gap
exposed/no gap
40
covered/gap
covered/no gap
20
χ² = 1.13, df = 4, p = 0.77
0
0
2
4
6
8
10
Time after transplantation (weeks)
Burmeier & Jensen (2009)
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Flooding, competition: Summary

Apium repens under „coastal conditions“?
• Very tolerant to submergence,
• but not by salt water (long-term)

Competition:
• Apium repens depends on disturbances
Æ Low competitive ability!
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Experimental ecology: Germination & dispersal

Temperature requirements
• Thermogradient-Incubator
• 7 levels of temperature (from 5 °C to 35 °C)
Dormancy and light requirements
• Stratification (cold-wet treatment, yes/no), light (yes/no)
• Constant vs. fluctuating temperature
(15, 20, 5/15, 10/20 °C)
Flooding tolerance of germination
• 4 flooding regimes + control
1 x 0,5; 1 x 1; 1 x 2; 2 x 1 weeks
Dispersal ecology: Seed bank, seed buoyancy
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Germination ecology: Temperature requirements

Germination at 5 - 35 °C
Optimum at 20°C
Reduction at high (and
low) temperatures
Burmeier & Jensen (2008)
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Germination ecology: Fluctuating temperatures

Seeds with primary
dormancy show
reduced germination at
constant temperature
Burmeier & Jensen (2008)
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Germination ecology:
Dormancy and light requirement

Light requirement with primary dormancy
Dormancy is broken by cold-wet stratification
Stratified seeds do not need light for germination
Burmeier & Jensen (2008)
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Germination ecology: Flooding tolerance

Gemination possible
during flooding
Highest germination at
constant conditions
Burmeier & Jensen (2008)
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Regeneration ecology: Summary

Cold-wet statification or light is required for germination
Also germinate during or after flooding
Æ Germination requirements not highly specific

Seed bank:
• Viable seeds were found in the top soil (-5/-10 cm depth)
Æ at least short-term persistent seed bank
Dispersal:
• Seeds can float > 50 days (in the greenhouse),
but sink with heavy rainfall
• sites mostly near small (vernal) water bodies
Æ short-distance dispersal by water (also ramets)
Æ Seed production limited (?)
Æ Dispersal limition (?)
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
How can we protect present populations?
•
Maintain (or improve) hydrology
•
Maintain disturbance regime
•
Create gaps in autumn to enhance
autumn germination (?)
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Establishment of new populations

3 Sites close to the island of Fehmarn
• Eichholzniederung (EH), Hohwacht (HW),
Neustädter Binnensee (NB)
• Planting in 2007 (EH, HW) and 2008 (NB)
Experimental design
• Creation of small water bodies in large-scale
grazing landscapes
• Grazing (yes/no)
• Each 3 transects along a hydrological gradient
• 3 „plant types“ (seedlings, runners, sods)
• Planting of 200 individuals per site
Monitoring
• Monthly monitoring between May and October
2007 to 2010
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Establishment of new populations: Sites
Eichholzniederung
Fehmarn
Sundwiesen
Hohwacht
Neustädter Binnensee
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Establishment of new populations:
Experimental design
Teich
Kleingewässer
small
water body
Hohwacht
fence
Zaun
P
B
6
1
GPS 1
GPS 2
2
5
4
3
Eichholzniederung
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Grazing and cover 2007
90
80
June
June
2007
July
July
2007
August
August
2007
Sept.2007
September
October
October
2007
Hohwacht
70
Cover [%]
Cover on 25x25 cm²Hohwacht
[%]
Eichholzniederung
60
50
40
30
20
10
0
90
Eichholzniederung
80
70
60
ungrazed
50
grazed
40
30
20
10
0
fenced unfenced
fenced unfenced
fenced unfenced
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
fenced unfenced
fenced unfenced
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Hydrology and cover 2007
100
Juni
June
2007
JulyJuli
2007
August
August
2007
Sept.2007
September
Oktober
October
2007
Hohwacht
Cover [%]
Cover on 25x25 cm² [%]
Eichholzniederung
Hohwacht
80
60
40
20
0
100
Eichholzniederung
80
60
1: high
5: low
40
20
0
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
Position along the hydrologic gradient
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Plant type and cover 2007
90
June 2007
July 2007
Juni
80
August 2007
Juli
August
September 2007
Sept.
October 2007
Oktober
Hohwacht
70
Cover [%]
Cover on 25x25 cm² [%]
Eichholzniederung
Hohwacht
60
50
40
30
20
10
0
90
Eichholzniederung
80
70
60
50
1: Seedlings
40
2: Runners
30
3: „Sods“
20
10
0
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
Plant type
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Cover from 2007 to 2010
Location: Neustadt
Location: Eichholz
Cover of Apium repens [%]
Cover
on 25x25 cm² [%]
Location: Howacht
100
80
2007
2008
2009
2010
Hohwacht
60
40
20
0
100
80
Eichholzniederung
60
40
20
0
100
Mean ± SE
80
60
Neustädter
Binnenwasser
not planted yet
40
ungrazed
20
grazed
0
grazed
Year: 2007
ungrazed
grazed
ungrazed
grazed
Year: 2008
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
ungrazed
Year: 2009
grazed
ungrazed
Year: 2010
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Conclusions

Is Apium repens rare due to
• …specific habitat requirements?
• …low competitive ability?
• …narrow regeneration niche?
• …dispersal limitation?
No
Yes
No
Probably
How can we protect present populations?
Æ Maintain hydrology and disturbances

(How) can we establish new populations?
Æ Yes, we can…. (sometimes)
• With seedlings, runners or sods
• With appropriate hydrology and disturbance regime
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Thank you for your attention!
Apium repens!
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Site conditions: Soil parameters
Burmeier & Jensen (2009)

pH-value ± neutral
Narrow C/N-ratio
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen

High range of C and
nutrient contents
fluctuate/deviate strongly
LIFE BaltCoast – Final Seminar
28.08.12
Germination ecology: Dormancy and light
requirement
Pre-treatment
dry storage
cold stratification
Light regime
light
darkness
light
darkness
light
darkness
light
darkness

Incubation temperature
[°C]
15
15
20
20
15
15
20
20
Germination
percentage
88.60 ± 2.23
0
91.78 ± 3.15
0
97.43 ± 1.29
70.77 ± 6.28
88.57 ± 4.29
80.42 ± 3.40
Light requirement with primary dormancy
Dormancy is broken by cold stratification
Stratified seeds without light requirement
for germination
Burmeier & Jensen (2008)
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Einleitung
Ökologie
Standort
Ansiedlung
Ausblick
Grazing and cover 2008
90
80
Juni
Juli
August
Septem.
Oktober
Hohwacht
Lokalität: Eichholz
Deckung [%]
Cover on
25x25 cm² [%]
Lokalität: Hohwacht
70
60
50
40
30
20
10
0
90
70
Eichholzniederung
60
ungrazed
50
grazed
80
40
30
20
10
0
Brache
Weide
Brache
Weide
Brache
Weide
Brache
Weide
Brache
Weide
Nutzung
K. A.
Jensen
Wanner,
& S.S.
Burmeier
Burmeier, J. Schwerdtfeger
NNA –
& Wiederansiedlung
K.
LIFE
von TierBaltCoast
und Pflanzenarten
– Final Seminar
Jensen
28.08.12
09.03.09
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
Summary

Site conditions
• Strong fluctuations of groundwater levels, submergence in spring
• pH close to 7; narrow C/N-ratio; otherwise unspecific
Competition, disturbance, flooding tolerance
• Low competitive ability, depends on disturbances
• tolerant against flooding of freshwater
Germination ecology
• Germination requirements: primary dormancy, stratification, light
requirement, temperature fluctuations, temperature range comparable
to other species of Central European wetlands, but:
• Germination possible also submerged
Establishment of new populations
• Impact of management/grazing/mowing, hydrology and year on
establishment success
• Plant type not relevant
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12
Introduction
Habitat
Experimental ecology
(Re)Introduction
Conclusions
THM
(Re)Introduction of Apium repens seems possible
Specific knowledge of population ecology and
habitat requirements for (re)introduction projects
necessary
A. Wanner, S. Burmeier, J. Schwerdtfeger & K.
Jensen
LIFE BaltCoast – Final Seminar
28.08.12

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