PDF Crozets Kerguelen Marion & Prince Edward Macquarie

(1)

Heard & McDonald Kerguelen

Crozets Marion &

Prince Edward

Macquarie

(2)

Sub-Antarctic islands are part of the Tundra Biome.

In the Northern Hemisphere, tundra vegetation covers c 6.3 million km

²

.

Sub-Antarctic Islands: ca. 6000 km

²

are ice free (potentially vegetated).

(Marion and Prince Edward Islands 370 km

²

).

However, all tundra biome vegetation types are represented on the two islands

Sub-Arctic

Photo: Ron Niebrugge

Boggy heaths

Photo: Patrick Endres

Arctic

Moraine flushes

Subantarctic

(3)

Arctic

Photo: David Orlovich

Arctic

Cushion plant fellfields

Subantarctic

(4)

Photo: David Orlovich

Subarctic

Freshwater wetlands

Photo: Croll et al. 2005. Science vol 307

Subarctic

Tussock grasslands

Subantarctic

(5)

Photo: Kate Harris,

Copyright Univ. North Carolina at Chapel-Hill

Antarctica

Arctic

Polar Barrens, Polar Desert

Sub-antarctic

(6)

A vegetation type that is rare in NH tundra

“Biotic” vegetation

(7)

Hence, studies on sub-Antarctic islands provide insights into tundra ecology

• But, since the islands are so undisturbed by factors that make interpreting the results of studies from other ecosystems so difficult ….

• the results of ecological studies on them are significantly adding to ecological theory in general.

Plus:

sub-Antarctic islands are experiencing intense climate change.

Plus:

they are experiencing the introduction of new organisms, mostly through human activities.

- Wonderful opportunities to study (at ecosystem, population,

organism levels) responses to these perturbations.

(8)

Heard & McDonald Kerguelen

Crozets Marion &

Prince Edward

Macquarie

(9)

Biological Conservation (2013) 161:18-27

Human activities, propagule pressure and alien plants in the sub-Antarctic: Tests of generalities and

evidence in support of management

Peter C. le Roux, et al.

Oecologia (2008) 155:831–844

Spatial variation in plant interactions across a severity gradient in the sub-Antarctic

Peter C. le Roux • Melodie A. McGeoch

Geomorphology (2009) 107:139–148

Interactions between a cushion plant (Azorella selago) and surface sediment transport on sub- Antarctic Marion Island

N.S. Haussmann, M.A. McGeoch, J.C. Boelhouwers

Acta Oecologica (2010) 36: 299-305

Contrasting nurse plants and nurse rocks: The spatial distribution of seedlings

of two sub-Antarctic species

N.S. Haussmann, M.A. McGeoch, J.C. Boelhouwers Global Change Biology (2005) 11: 1628–1639

Effects of a short-term climate change experiment on a sub-Antarctic keystone plant species PETER C. LE ROUX, MELODIE A. MCGEOCH, MAWETHU J . NYAKATYA and STEVEN L . CHOWN

(10)

(11)

(12)

Classification Schemes for Marion Island Vegetation

Salt Spray Complex, Swamp Complex, Biotic Complex,

Wind Desert Complex,

Slope Complex,Springs and Drainage line complex Lowland slopes complex

Huntley (1971)

Ecological classification.

13 plant communities, in 5 community complexes

Gremmen (1981) Phytosociological classification.

41 plant communities, in 6 community complexes

Smith and Steenkamp (2001),

modified by Gremmen and Smith (2008)

Habitat classification (botanical, soil chemistry, soil microbiology, microclimate).

23 habitats, in 6 habitat complexes

Mire Complex

Biotic grassland Complex Biotic Herbfield Complex

Fellfield Complex Fellfield Complex, Polar Desert Complex

(13)

Percentage cover of main vegetation types on part of the

eastern coastal plain.

From 6 km of transects Surveyed

from 1972 to 2011.

(14)

Other objectives and achievements of the plant ecological research on the islands

- To get GIRLS on the island

(15)

First (1971) SASCAR (now SANAP),

statement of aims for the Biological Program on Marion Island:

- "to obtain a better insight into the interesting food cycles of the Marion Island ecosystem, including, Primary production, decomposition,

Inputs, outputs and cycling of nutrients”

Overall objective: To model ecosystem function on Marion Island But, before the girls….

These aims were influenced by the International Biological Programme (1967-74)

(16)

Our first model –nutrient inputs by seals and seabirds (1979)

(In 1982 this model was refined

using an IBM PC)

(17)

Nutrient input to Marion Island through guano and moulted feathers of suface nesters

12 000 -11% -6%

-37%

2 000

-38%

-6%

5 000

-47%

600 000 100 000 180 000

Nitrogen, coast

kg N m-2 y-1 1974

Nitrogen, inland

1974 1974 1974

kg P m-2 y-1 1974 kg Ca m-2 y-1

Phosphorus,

coast Phosphorus,

inland Calcium,

coast Calcium, inland

1974

2002 2002 2002 20022002 2002

Burrowing birds???

(18)

(19)

Annual primary production (above plus belowground)

2000

1000

0 (g m-2 y-1 )

Northern Hemisphere tundras

M M

SG SG

SG

M

M SG

MQ

Sub-Antarctic

Temperate grasslands

(20)

Nutrient cycling in a mire-grassland

^{ASB 0.02}^{ASV 0.37}_{ANV 0.06}

ASB 0.31

BSV 1.86 TAV 0.50

TBV 0.45 ALB

0.27

ALV 0.05

UTV 1.86

BLV 1.81 Soil total: 27.03

Soil available: 5.03 Soil solution: 2.24

UTB 0.27

L 9.62 R 10.35

ASB 0.09 ASV 0.53 ANV 0.39 ASB 0.14

BSV 2.60 TAV 0.98

TBV 0.05 ALB

0.89

ALV 0.93

UTV 3.03

BLV 2.10 Soil total: 64.25

UTB 0.89

L 0.57 R 0.37

ASB 0.03 ASV 0.34 ANV 0.15 ASB 0.19

BSV 2.05 TAV 0.57

TBV 0.22 ALB

0.15

ALV 0.35

UTV 1.63

BLV 1.28 Soil total: 19.21

Soil available: 0.67 Soil solution: 0

UTB 0.15

L 0.00 R 0.00

ASB 0.11 ASV 2.27 ANV 0.35 ASB 1.92

BSV 2.57 TAV 2.94

TBV 2.09 ALB

1.47

ALV 0.85

UTV 3.85

BLV 3.00 Soil total: 15.51

UTB 1.47

L 0.56 R 0.39

ASB 0.07 ASV 0.66 ANV 0.41 ASB 0.25

BSV 2.74 TAV 0.87

TBV 0.11 ALB

0.87

ALV 0.76

UTV 21.42

BLV 1.98 Soil total: 20.89

UTB 0.87

L 1.94 R 1.24

ASB 0.46 ASV 4.01 ANV 4.83 ASB 1.79

BSV 30.58 TAV 5.56

TBV 0.69 ALB

3.41

ALV 4.87

UTV 21.42

BLV 16.55 Soil total: 387.54

Soil available: 0.69 Soil solution: 0

UTB 3.41

L 0.00 R 0.21

F 0.09

NITROGEN PHOSPHORUS POTASSIUM

SODIUM

CALCIUM MAGNESIUM

Sorry, Rosie, microbes alone not good enough

(21)

Litter or peat,

with or without

macroinvertebrate

(22)

(23)

0 10 20 30 40 50 60 70

0 100 200 300 400 500 600 700

Days of incubation

Release of NH

₄

-N from Azorella selago litter in the presence and absence of a moth larva

+ larva

- larva

Soil macroinvertebrates are associated with 95%

of nutrient mineralization in a mire grassland

(24)

House mice Mus musculus

Introduced early 1800s

One of the most southerly “feral”

populations

Population has increased

(25)

Plant material

Other (feathers, vertebrate muscle)

Insects, earthworms

What do mice eat? Importance values in the contents of 836 stomachs

Implications for nutrient cycling?

Other aspects of ecosystem functioning?

Sheathbills?

(26)

Climatic and edaphic aridity Biotic influence

(manuring)

Climatic and edaphic wetness

Physiological aridity (salinity)

Axis 2 Axis 1

B

Climatic and edaphic aridity Biotic influence

(manuring)

Climatic and edaphic wetness

Physiological aridity (salinity)

Axis 2 Axis 1

These vectors represent the main

“ecological forcing variables” that determine vegetation succession at the island

Monte Carlo permutations

suggest that three axes account for 80 to 84% of the variance in the plant guild – soil chemistry – soil microbiology data

(27)

0 12 0

12

Seabird / seal manuring (“Biotic” habitats)

Wetness (mire and bog

habitats)

Climatic aridity

(Fellfield habitats) Physiological aridity

(saltspray habitats)

Primary

production

(28)

0 2 4 6 8 10 12 0

2 4 6 8 10 12

Seabird / seal manuring (“Biotic” habitats)

Wetness (mire and bog

habitats)

Climatic aridity

(Fellfield habitats) Physiological aridity

(saltspray habitats)

Soil heterotrophic activity

(CO

₂

efflux)

(29)

Annual primary production (above- plus belowground)

=Carbon in

< 1

1 - 10 10 - 100

100 - 200 200-400 400-500 500-800

800-1200 1200-1400

g m^-2 y^-1 Total island: 134 523 tonnes per year

(30)

1950 1960 1970 1980 1990 2000 YEAR

5.0 5.5 6.0 6.5 7.0

Annual mean temperature (o C)

3000

2800

2600

2400

2200

2000 1800

Warming/drying scenario

(2°C, 20% decline in soil moisture)

Recovered bird populations

scenario

(31)

Increase g m-2 y-1

0 0 - 1 1 - 5 5 - 10 10 - 15

15 - 20 20 - 25 25 - 50 50 - 100

>100

Increase in annual primary production - warming/drying scenario

100

80

60

40

20

0

0 200 400 600 800 1000 1200

Change (g m-2y-1)

Altitude

Increase in annual primary production – recovered bird populations scenario

100

80

60

40

20

0

0 200 400 600 800 1000 1200

Change (g m-2y-1)

Altitude

Total island:

140057 tonnes y^-1 (increase 4.1%)

Total island:

141972 tonnes y^-1 (increase 5.5%)

(32)

Total island: 86 021 tonnes C per year Annual total soil respiration

= Carbon out

0 - 50 50 - 100 100 - 200 200 - 300 300 - 400 400 - 500 500 - 700 700 - 900

>900 g Carbon

m^-2 y^-1

(33)

Change in annual total soil respiration – recovered bird populations scenario 0

0 - 1 1 - 2 2 - 5 5 - 10 10 - 15 15 - 20 20 - 50 100 - 150

(-2) - (-5)

g C m^-2 y^-1 Change in annual total soil respiration – warming, drying scenario

0 200 400 600 800 1000 1200

Altitude (m)

0 20 40 60 80 100 120 140

Change in annual total respired Carbon (g C m-2 y-1 )

Total island:

87 916 tonnes C y^-1 (increase 2%)

0 200 400 600 800 1000 1200

Altitude (m)

0 20 40 60 80 100 120 140

Change in annual total respired Carbon (g C m-2 y-1 )

Total island:

92 284 tonnes C y^-1 (increase 7%)

(34)

Where to now?

Vegetation map of the island?

Explain the top down ecosystem/community/habitat results using bottom up studies-

autecological and ecophysiological investigations of particular plant species.

Especially of the bryophytes.

Evolution of traits/tradeoffs to cope with island conditions.

Nature/nurture?

Coping with change.

Indigenous vs alien species pairs/triplets/quadruplets – predict what traits enable successful invasion.

Freshwater algae – 106 genera, most diverse organism group on the island- Ecology/ecophysiology, primary production?

PDF Crozets Kerguelen Marion & Prince Edward Macquarie

Sub-Antarctic islands are part of the Tundra Biome.

In the Northern Hemisphere, tundra vegetation covers c 6.3 million km

.

Sub-Antarctic Islands: ca. 6000 km

are ice free (potentially vegetated).

(Marion and Prince Edward Islands 370 km

).

However, all tundra biome vegetation types are represented on the two islands

Boggy heaths

Moraine flushes

Cushion plant fellfields

Freshwater wetlands

Tussock grasslands

Polar Barrens, Polar Desert

A vegetation type that is rare in NH tundra

“Biotic” vegetation

Hence, studies on sub-Antarctic islands provide insights into tundra ecology

• But, since the islands are so undisturbed by factors that make interpreting the results of studies from other ecosystems so difficult ….

• the results of ecological studies on them are significantly adding to ecological theory in general.

Plus:

sub-Antarctic islands are experiencing intense climate change.

Plus:

they are experiencing the introduction of new organisms, mostly through human activities.

- Wonderful opportunities to study (at ecosystem, population,

organism levels) responses to these perturbations.

Classification Schemes for Marion Island Vegetation

Other objectives and achievements of the plant ecological research on the islands

- To get GIRLS on the island

Our first model –nutrient inputs by seals and seabirds (1979)

(In 1982 this model was refined

using an IBM PC)

Burrowing birds???

Annual primary production (above plus belowground)

Nutrient cycling in a mire-grassland

Sorry, Rosie, microbes alone not good enough

Litter or peat,

with or without

macroinvertebrate

Days of incubation

Release of NH

-N from Azorella selago litter in the presence and absence of a moth larva

What do mice eat? Importance values in the contents of 836 stomachs

Primary

production

Soil heterotrophic activity

(CO

efflux)

Warming/drying scenario

(2°C, 20% decline in soil moisture)

Recovered bird populations

scenario

Where to now?

Also to SASCAR, SACAR, SANAP, CSP, FRD, NRF,

DOT, DEAT, DEA for support,

And to you for attending this talk

Thanks to the many people who have worked on the projects

described,