Richard Thackway, VAST Transformations: Tracking sand dune transformation before, during and after...

Tracking sand dune transforma2on before, during and a5er sand dune mining,

Myall Lakes, NSW, a case study

Richard Thackway

The 14th Annual Australian Journal Mining's Mineral Sands Conference Rydges, Melbourne, 4th & 5th March 2014

Outline

•  VAST-‐2 system •  Case study -‐ Bridge Hill Ridge, Myall Lakes, NSW •  Understanding causes and effects = change in condiOon •  Tracking change and trend before, during and aPer mining •  InterpreOng ecological change and trend •  Lessons from the case study

VAST = VegetaOon Assets States and TransiOons

VAST – An ecological systems approach

•  Making the complex simple by: –  AccounOng for effects of land management change over Ome

–  Linking ecological change to land management

Assessing ecological change before, during and a5er sand dune mining –

using VAST

Defini2ons -‐ Condi2on and transforma2on

•  Change in a plant community (type) due to effects of land management pracOces:

–  Structure

–  ComposiOon

–  RegeneraOve capacity

•  Resilience = the capacity of an plant community to recover to a reference state following a change/s in land management

•  TransformaOon = changes to vegetaOon condiOon over Ome •  CondiOon, resilience and transformaOon are assessed relaOve

to fully natural a reference state

Vegeta2on condi2on

VAST-‐2 tracks the effects of land management prac2ces over 2me

At the land parcel level on-‐ground management acOons are the primary cause of changes in vegetaOon condiOon: •  Modifying •  Removing and replacing •  Enhancing •  Restoring •  Maintaining •  Improving

Biodiversity outcomes can be pracOcally tracked and reported using: •  Criteria or Key Result Areas and •  Indicators or Key Performance Indicators

1925

Occupation

Relaxation

Anthropogenic change

Net benefit

time

1900 2025 1950

Reference

change in vegetaO

on

indicator o

r ind

ex

1850 1875 1975 2000

VAST classes

VAST-‐2 model of ecosystem change (causes & effects)

VAST-‐2 focuses on tracking effects of land management on key ecological criteria

Soil

Vegeta2on

RegeneraOve capacity/ funcOon

VegetaOon structure & Species composiOon

1.  Soil hydrological status 2.  Soil physical status 3.  Soil chemical status 4.  Soil biological status 5.  Fire regime 6.  ReproducOve potenOal 7.  Overstorey structure 8.  Understorey structure 9.  Overstorey composiOon 10.  Understorey composiOon

VAST = VegetaOon Assets States and TransiOons NVIS = NaOonal VegetaOon InformaOon System

VI V IV III II I 0

Native vegetation cover

Non-native vegetation cover

Increasing modification caused by use and management

Transitions = trend

Vegetation thresholds

Reference for each veg type (NVIS)

VAST -‐ A framework for assessing & repor2ng vegeta2on condi2on

Condition states

Residual or unmodified

Naturally bare

Modified Transformed Replaced -Adventive

Replaced - managed

Replaced - removed

Thackway & Lesslie (2008) Environmental Management, 42, 572-‐90

DiagnosOc aeributes of VAST states: •  VegetaOon structure •  Species composiOon •  RegeneraOve capacity

NVIS

Current datasets are snapshots but not 2me series

Thackway & Lesslie (2008) Environmental Management, 42, 572-90

NB: Input dataset biophysical naturalness reclassified using VAST framework

/ replaced

/ unmodified

VAST 2009

Veg condi2on derived by classifying &

mapping effects of land management prac2ces

NaOve

Generate total indices for ‘transformaOon site’ for each year of the historical record. Validate using Expert Knowledge

•  Compile and collate effects of land management on criteria (10) and

indicators (22) over Ome. •  Evaluate impacts on the plant

community over Ome

Transforma2on site •  Compile and collate effects of land management on criteria

(10) and indicators (22)

Reference state/sites

Score all 22 indicators for ‘transformaOon site’ relaOve to the ‘reference site’. 0 = major change; 1 = no change

Derive weighted indices for the ‘transformaOon site’ i.e. regeneraOve capacity (58%), vegetaOon structure (27%) and species composiOon (18%)

by adding predefined indicators

General process for tracking change over 2me using the VAST-‐2 system

Case study – Bridge Hill Ridge

Geographical and historical context

High sand dune case study

Sand mining path

Bridge Hill Ridge

Figure: Barry Fox

Transforma2on site

Case study site Field visit January 2014

(Lat -‐32.404, Long 152.496)

Smiths Lake

0 1000 2000

Kilometers Sand mining

path

Bridge Hill Ridge, 2011

Case study site -‐ Field visit January 2014

Smiths Lake

Bridge Hill Ridge, 1976 & 1991

1976 1991

Source: Geoscience Australia, © Australian Titanium Minerals Industry

Smiths Lake

Bridge Hill Ridge 1975

Smiths Lake

Regenerating Mine Path

Sandmining Dredge

Photograph: Barry Fox


Smiths Lake

Regenerated Mine Path



Regenerated Mine Path

Smiths Lake

Establishing and documen2ng the Reference and Transforma2on

site

Plant community Eucalyptus pilularis and Angophora costata

Soil landscape unit

Upper slopes and crests of the high dune

Establishing the Reference and Transforma2on site

Source: Bunning Report 1974

Reference Transforma2on

Based on Myerscough and Carolin (1986)

Reference state plant community (shaded area)

Eucalyptus pilularis Angophora costata Banksia serrata

Source: Coffey and Hollingsworth, 1973. Map. No. 3.1.5

Reference state plant community (shaded area)

Source: Coffey and Hollingsworth, 1973. Map. No. 2.3.1.4

Reference state plant community

Mined area

Smiths Lake

Reference site/ state

Photographs: Richard Thackway

Transforma2on site

Sandmining – land management prac2ces

Source: Coffey and Hollingsworth, 1973. Map. No. 3.1.5

Unmined

Pond

Mining surface

Reshaped landform

Tailings

Mining direc2on

100 0 100 200 300

Meters

Sandmining -‐ the process

250m x 150m

Topsoil briefly stockpiled <10 days

Timber harvested and remaining trees and vegetation removed

1974 (0 years old)

Photographs: Barry Fox

Sand sprayed and dried and re-shaped as a

contoured dune

Sandmining Dredge

Original Eucalypt open forest

Dredge Pond

Smiths Lake

Dredge Pond

1974 (0 years old)

Photographs: Barry Fox

Transforma2on site

Restora2on – land management prac2ces

1974-‐75 (0-‐6 months old)

Topsoil spread over reshaped sand dune

Sorghum cover crop planted

1974 (One month old) 1975 (< 6 months old)


1975 (1 year old)

Dead and dying sorghum plants < 1% reseeding Photograph: Barry Fox

1976-‐77 (1.5 -‐ 2 years old)

Substantial Acacia

regrowth begins

Isolated Acacia plants in sorghum compartment

1976-77 (2 Years old) 1975-76 (1.5 years old)


1978 (3 years old)

Acacia die-off beginning

Substantial Acacia regrowth


1979 (4 years old)

Substantial Acacia die-off Photograph: Barry Fox

1981 (6 years old)

Increasing abundance of native species growing among dead Acacia and native grasses


Substantial Acacia Regrowth

Substantial bare sand and open space between sapling trees with sparse leaf litter

1991 (12 years old)


2014 (39 years old)

Photographs: Richard Thackway

Integra2on using VAST-‐2

Normalising the age of regenera2on

Figure: Barry Fox

Generate total indices for ‘transformaOon site’ for each year of the historical record. Validate using Expert Knowledge

•  Compile and collate effects of land management on criteria (10) and

indicators (22) over Ome. •  Evaluate impacts on the plant

community over Ome

Transforma2on site •  Compile and collate effects of land management on criteria

(10) and indicators (22)

Reference state/sites

Score all 22 indicators for ‘transformaOon site’ relaOve to the ‘reference site’. 0 = major change; 1 = no change

Derive weighted indices for the ‘transformaOon site’ i.e. regeneraOve capacity (58%), vegetaOon structure (27%) and species composiOon (18%)

by adding predefined indicators

General process for tracking change over 2me using the VAST-‐2 system

Condi2on components (3)

[VAST]

Key Result Areas (10) Key Performance Indicators

(22) Re

gene

ra2v

e capa

city

Fire regime 1. Area /size of fire foot prints 2. Number of fire starts

Soil hydrology 3. Soil surface water availability 4. Ground water availability

Soil physical state

5. Depth of the A horizon 6. Soil structure

Soil nutrient state

7. Nutrient stress – rundown (deficiency) relaOve to soil ferOlity 8. Nutrient stress – excess (toxicity) relaOve to soil ferOlity

Soil biological state

9. Recyclers responsible for maintaining soil porosity and nutrient recycling 10. Surface organic maeer, soil crusts

ReproducOve potenOal

11. ReproducOve potenOal of overstorey structuring species 12. ReproducOve potenOal of understorey structuring species

Vegeta2o

n structure

Overstorey structure

13. Overstorey top height (mean) of the plant community 14. Overstorey foliage projecOve cover (mean) of the plant community 15. Overstorey structural diversity (i.e. a diversity of age classes) of the stand

Understorey structure

16. Understorey top height (mean) of the plant community 17. Understorey ground cover (mean) of the plant community 18. Understorey structural diversity (i.e. a diversity of age classes) of the plant

Species

Compo

si2o

n Overstorey composiOon

19. DensiOes of overstorey species funcOonal groups 20. RelaOve number of overstorey species (richness) of indigenous :exoOc spp

Understorey composiOon

21. DensiOes of understorey species funcOonal groups 22. RelaOve number of understorey species (richness) of indigenous :exoOc spp

VAST-‐2 key ecological criteria & indicators

Reference state

Transforma2on site

Fire regime * * Soil hydrology * * Soil physical state * ** Soil nutrient state ** * Soil biological state * * Reproduc2ve poten2al *** *** Overstorey vegeta2on structure *** **

Understorey vegeta2on structure *** *** Overstorey species composi2on *** ***

Understorey species composi2on *** ***

Popula2ng the VAST-‐2 criteria

*** QuanOtaOve data /info * QualitaOve data /info

1

3

10

22

Diagno

s2c

afrib

utes

Vegeta2on Transforma2on

score

Afrib

ute

grou

ps

VegetaOon Structure (27%)

Overstorey

(3)

Understorey

(3)

Species ComposiOon

(18%)

(2)

Understorey Overstorey

(2)

RegeneraOve Capacity (55%)

Fire

(2)

Reprod potent

(2)

Soil

Hydrology

(2)

Biology

(2)

Nutrients

(2)

Structure

(2) Indicators

VAST-‐2 integra2on hierarchy

Importance of dynamics

Rainfall is assumed to be main driver of system dynamics •  Period 1900 -‐ 2013 •  Average seasonal rainfall (summer, autumn, …) •  Rainfall anomaly is calculated above and below the mean •  Two year running trend line fieed

NB: Must calibrate remote sensing to account for dynamics •  e.g. ground cover, greenness and foliage projecOve cover

Seasonal rainfall anomaly (Lat -‐32.404, Long 152.496)

-‐2

-‐1

0

1

2

3

1901

1904

1907

1910

1913

1916

1919

1922

1925

1928

1931

1934

1937

1940

1943

1946

1949

1952

1955

1958

1961

1964

1967

1970

1973

1976

1979

1982

1985

1988

1991

1994

1997

2000

2003

2006

2009

2012

Spring

-‐3 -‐2 -‐1 0 1 2 3 4 5

1901

1904

1907

1910

1913

1916

1919

1922

1925

1928

1931

1934

1937

1940

1943

1946

1949

1952

1955

1958

1961

1964

1967

1970

1973

1976

1979

1982

1985

1988

1991

1994

1997

2000

2003

2006

2009

2012

Winter

-‐4

-‐2

0

2

4

6

1901

1904

1907

1910

1913

1916

1919

1922

1925

1928

1931

1934

1937

1940

1943

1946

1949

1952

1955

1958

1961

1964

1967

1970

1973

1976

1979

1982

1985

1988

1991

1994

1997

2000

2003

2006

2009

2012

Autumn

-‐2

-‐1

0

1

2

3

1901

1904

1907

1910

1913

1916

1919

1922

1925

1928

1931

1934

1937

1940

1943

1946

1949

1952

1955

1958

1961

1964

1967

1970

1973

1976

1979

1982

1985

1988

1991

1994

1997

2000

2003

2006

2009

2012

Summer

Source: BOM

Are we there yet?

Results

Key Result Areas – Regenera2ve capacity

Key Result Areas – Vegeta2on structure

Key Result Areas – Species composi2on

VAST-‐2 Report Card

Lessons from Bridge Hill Ridge

•  BHR is atypical of the usual restoraOon effort and regeneraOon outcome that follows sand mining

•  The restoraOon effort and regeneraOon outcome at BHR is very good

•  A great deal more money was spent on BHR than other similar mining paths

•  The quality of the restoraOon effort and regeneraOon outcome is directly related to the amount spent

What else could be done to improve the site toward the reference state?

•  Consider establishing an appropriate experimental fire regime checking for weed incursions

•  Allow more Ome for incremental change in: –  Understorey Species Composi<on –  Overstorey Vegeta<on Structure –  Reproduc<ve Poten<al (Understorey)

Conclusions

•  The VAST-‐2 report card helps tell the story of change and trend in vegetaOon condiOon

•  The restoraOon effort and regeneraOon outcome at BHR is very good

•  A similar approach could be applied to exisOng, proposed and future mined sites

VAST helps in ‘telling the story’

VAST helps in ‘telling the story’

Predic2ons of mature forest (Bunning’s Enquiry 1974)

More info & Acknowledgements More informa2on hep://www.vaseransformaOons.com/ hep://portal.tern.org.au/search hep://aceas-‐data.science.uq.edu.au/portal/

Acknowledgements •  Mae Bolton, Barry Fox, Mike Dodkin and Shane Cridland assisted with data and

assessment •  University of Queensland, Department of Geography Planning and

Environmental Management for ongoing research support •  Many public and private land managers, land management agencies,

consultants and researchers have assisted in the development of VAST-‐2

Richard Thackway, VAST Transformations: Tracking sand dune transformation before, during and after...

Business

Transcript of Richard Thackway, VAST Transformations: Tracking sand dune transformation before, during and after...