1. Great Barrier Reef Report Card 2015 – Burdekin: Ground Cover
Presentation title

2. Catchment indicators Paddock Catchment Marine
Sampling and remote sensing
Measuring practices
On-farm monitoring
Water quality monitoring
Coral monitoring
Paddock modelling
Catchment modelling
Seagrass monitoring

3. Background

4. Bare Ground Index

5. Ground Cover Index Derived from Landsat using linear regression
Reports percentage cover at pixel scale 25m x 25m
Calibrated/validated against ~500 sites with RMSE of ~13%
Weaknesses
Only where foliage <15 %
dry season only
Modellers and others report it overestimates
Estimating C-Factor Values for Great Barrier Reef Catchments using Satellite Derived Ground Cover Measurements

6. Fractional Cover
Green Cover
Non-Green Cover
Bare Ground
TOTAL COVER

7. Increased Field Sites

8. Opening of Landsat Archive

9. Fractional Cover Index
Reports on percentage green, dry cover and bare ground at Landsat pixel scale
Produced using spectral un-mixing algorithm and validated against 1500 sites
Around the same level of accuracy
Far greater temporal frequency
Estimating C-Factor Values for Great Barrier Reef Catchments using Satellite Derived Ground Cover Measurements

10. Ground Cover

11. Fractional Ground Cover
Green Cover
Non-Green Cover
Bare Ground
GROUND COVER
TOTAL COVER

12. Persistent Green
Trees
All Green Cover

13. Process
Fractional Cover
Persistent Green
Cover Under Trees

14. Fractional Ground Cover
Cover under trees
Fractional Ground Cover

16. Things to know

17. Fractional Ground Cover
Old Ground Cover
Fractional Ground Cover
~38% of reef plan reporting area
~94% of reef plan reporting area

18. Patches

19. Seasonal Cover Composite image Medoid: multi- dimensional median
High quality seasonal product
Estimating C-Factor Values for Great Barrier Reef Catchments using Satellite Derived Ground Cover Measurements

20. Visual vs Point Intercept Estimates of Cover

21. Field Estimates
Point intercept method for collection of ground cover data
3 transects in star formation covering a 1 ha area
Cover type (bare, green, dry) recorded at 1 m intervals at contact point
300 points in total
Estimating C-Factor Values for Great Barrier Reef Catchments using Satellite Derived Ground Cover Measurements

22. Visual vs Point Intercept Methods
Ability of the human eye to look 'through' pasture to delineate areas of bare ground, subsequently overestimating its proportion.
Murphy, S.R. & Lodge, G.M. (2002). Ground cover in temperate native perennial grass pastures. I. A comparison of four estimation methods. Rangeland Journal, 24(2), pp
Estimating C-Factor Values for Great Barrier Reef Catchments using Satellite Derived Ground Cover Measurements

23. 1:1 line 50% ‘Objective’ Cover = 24% Visual Cover
1:1 line
50% ‘Objective’ Cover
= 24% Visual Cover
Estimating C-Factor Values for Great Barrier Reef Catchments using Satellite Derived Ground Cover Measurements

24. Cover Estimation Exercise19 7 51 31 62 43 76 60 97 92
Estimating C-Factor Values for Great Barrier Reef Catchments using Satellite Derived Ground Cover Measurements

25. Results

26. Target: 70 per cent late dry season ground cover by 2018.
Good: Late dry season mean ground cover across grazing lands was 69 per cent.
The ground cover distribution for Burdekin provides a visual representation of the results. The proportion of the region with less than 70 per cent cover is shaded blue and labelled (48 per cent). The distribution of the long-term mean ground cover levels is displayed as the dashed line, and the 2015 distribution of ground cover levels is the solid line. The median of the long-term mean and 2015 cover are presented (vertical lines), with the actual median value in 2015 (70 per cent) shown in red at the base of the line.

27. Burdekin: Rainfall

28. Burdekin

29. Burdekin: Area under 70% Cover

30. Deciles
Compares season with all other seasons in record and ranks

31. Target: 70 per cent late dry season ground cover by 2018.
Good: Late dry season mean ground cover across grazing lands was 69 per cent.
The ground cover distribution for Burdekin provides a visual representation of the results. The proportion of the region with less than 70 per cent cover is shaded blue and labelled (48 per cent). The distribution of the long-term mean ground cover levels is displayed as the dashed line, and the 2015 distribution of ground cover levels is the solid line. The median of the long-term mean and 2015 cover are presented (vertical lines), with the actual median value in 2015 (70 per cent) shown in red at the base of the line.