The Australian Transect Network Bioclimatic gradients for assessing and

monitoring ecological change

Stefan Caddy-Retalic, Alan Andersen & Ian Fox

Terrestrial Environmental Research Network

ATN – Four primary transects

NATTNorth Australian Tropical Transect

SWATTSouth West Australian Transitional Transect

BATSBiodiversity and Adaptation Transect Sydney

TRENDTRansect for ENvironmental monitoring and Decision making

ATN – Four primary transects

Spinifex Hummock Grassland

Tropical Savanna

NATTNorth Australian Tropical Transect

SWATTSouth West Australian Transitional Transect

BATSBiodiversity and Adaptation Transect Sydney

Acacia Shrubland

TRENDTRansect for ENvironmental monitoring and Decision making

Eucalypt Open Forest

Subtropical forest

Eucalypt Open Woodland

Why bioclimatic transects?

• Scaling-up from local, plot-based studies

• Biogeographic framework for locating plots

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Why bioclimatic transects?

• Scaling-up from local, plot-based studies

• Developing, calibrating and validating ecological models and remote sensing products

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Why bioclimatic transects?

• Scaling-up from local, plot-based studies

• Developing, calibrating and validating ecological models and remote sensing products

• Identifying sensitive zones in relation to environmental stress and disturbance• Space as a proxy for time for climate-change research

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Key Science Questions

1. How do species abundances, richness and composition, and ecological function change along large-scale environmental gradients?

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Key Science Questions

1. How do species abundances, richness and composition, and ecological function change along large-scale environmental gradients?

2. Is there predictable variation in ecosystem resilience?

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Key Science Questions

1. How do species abundances, richness and composition, and ecological function change along large-scale environmental gradients?

2. Is there predictable variation in ecosystem resilience?

3. How might ecosystems respond to climate change?• Turnover in species, adaptive traits and genes

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ATN – NATT and TREND

NATT

TREND

Overarching research framework of responses of ecosystems to stress (PAM, AN) and disturbance (fire, grazing)

North Australian Tropical Transect IGBP-GCTE Global Network of Transects

DARWIN

TENNANT CREEK

500 mm

750 mm

1000 mm

1250 mm

1500 mm

Photos: Adam Liedloff

North Australian Tropical Transect

NATT Focal Areas

DARWIN

TENNANT CREEK

Growth of tagged trees

• Site every 100 km

• 12 eucalypts tagged per site

• Initial measurements 2000

• Re-measured 2012

1. Tree dynamics

Tree growth along NATT

200 400 600 800 1000 1200 1400 1600 18000

0.1

0.2

0.3

0.4

0.5

0

0.05

0.1

0.15

0.2

0.25

Median annual rainfall (mm)

DBH

incr

emen

t (cm

/yr)

Hei

ght i

ncre

men

t (m

/yr)

G. D. Cook, unpublished

Height (for tree with 25 cm dbh)

DBH

Monitoring tree dynamics using LiDAR

NATT Focal Areas

2. Carbon stocks and fluxes

0

0.2

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0.6

0.8

1

1.2

0 500 1000 1500 2000

Sand

Loam

Tree cover and rainfall

NATT Focal Areas

2. Carbon stocks and fluxes

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0.2

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0.8

1

1.2

0 500 1000 1500 2000

Sand

Loam

0

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8

0 1 2 3 4 5

log DBH (cm)

log

Bio

mas

s (kg

)

-1

0

1

2

3

4

5

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

log tree DBH (cm)

log

root

bio

mas

s (k

g/m

2)

Tree carbon stocks – above ground Tree carbon stocks – below ground

Tree cover and rainfall

Biomass as predicted by DBH

NATT Focal Areas

2. Carbon stocks and fluxes

• LiDAR for landscape-scale assessments

NATT Focal Areas

2. Carbon stocks and fluxes

• LiDAR

• Integration with flux-tower measurements

Collaborating institutions:

• CDU (Hutley and Maier)

• Max Planck (Levick)

0

20

40

60

80

100

120

1500 1250 1000 750 500

Annual rainfall (mm)

No

. sp

ecie

s

Sand

Loam

Plot (1 ha) richness

Tropical

Arid

Ants as a focal taxon for biodiversity studies

NATT Focal Areas

3. Biodiversity

Ant biogeographic discontinuities

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20

40

60

80

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120

1500 1250 1000 750 500

Annual rainfall (mm)

No

. sp

ecie

sSand

Loam

Plot richness

Mesic Semi-arid Arid

Finer resolution of the sensitive areas in relation to climate change

U.S. Fulbright PhD scholar Israel Del Toro, University of Amherst

NATT Focal Areas 4. Ecological processes - Fire

• 400,000 km2 burnt each

year

• Biodiversity declines

• GHG abatement

NATT Focal Areas

4. Ecological processes - Fire

0 200 400 600 800 1000 1200 1400 1600 18000

0.1

0.2

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0.8

f(x) = − 2.36773084380419E-07 x² + 0.00079202703125169 x − 0.145035160409551R² = 0.848854839692457

Mean % area burnt

Mean annual rainfall

NATT Focal Areas

4. Ecological processes - Fire

0 200 400 600 800 1000 1200 1400 1600 18000

0.1

0.2

0.3

0.4

0.5

0.6

f(x) = 1.7841553555E-07 x² − 0.000033497401229 x + 0.0105952164298R² = 0.787033057338807

Early dry season

0 200 400 600 800 1000 1200 1400 1600 18000

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

f(x) = − 4.151886199352E-07 x² + 0.00082552443248 x − 0.155630376839314R² = 0.689735719646058

Late dry season

Mean annual rainfall Mean annual rainfall

Transect for Environmental Monitoring and Decision-making

Vegetation turn-over quantifiedGuerin & Lowe EMAS 2012Guerin et al. 2013

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35 Plots

Soil characterisation

Floral composition

Vegetation structure

Ant communities

Metagenomics

Photopoints

Temperature loggers

δ13C & δ15N isotopes

Current and predicted future species distributions

Now

2050

Current and predicted future species distributions

Now

2050

Mapping sensitivity to

climate change

Detecting ecosystem changes over time: implications for the future

Orchids flowering 20 days earlier than 20 years ago

Flowering phenology

Detecting ecosystem changes over time: implications for the future

Orchids flowering 20 days earlier than 20 years ago

Hop Bush leaves narrowing over the last century

Flowering phenology Functional traits

Using new genomics techniques

Plants• DNA barcoding• Biogeography• Population Genetics/Genomics

Soils• Metabarcoding

McCallum et al AustEcol 2013

Gene turn-over in plants and soilGenomics, metagenomics and transcriptomics

Integrating information on biodiversity distribution and climate sensitivity for biodiversity resilience

• Weighted benefit maps for policy and land management decision makers

Connecting the public to research is a TREND priority.This should be a two-way dialogue.

Australian Transect Network

A powerful tool for enhanced ecosystem understanding and management in the face of climate change