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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
Bridge Hill Ridge 1991
Smiths Lake
Regenerated Mine Path
Photograph: Barry Fox
Bridge Hill Ridge 2011
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)
Photograph: Barry Fox
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)
Photograph: Barry Fox
1978 (3 years old)
Acacia die-off beginning
Substantial Acacia regrowth
Photograph: Barry Fox
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
Photograph: Barry Fox
Substantial Acacia Regrowth
Substantial bare sand and open space between sapling trees with sparse leaf litter
1991 (12 years old)
Photograph: Barry Fox
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 – 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