LAND COVER

OVERVIEW

Land cover refers to the observed physical and biological cover of the Earth’s surface and includes natural vegetation and abiotic (non-living) surface (SEEA Central Framework 2012).

Land cover data has been collated for the State of Queensland and its Natural Resource Management Regions (NRMRs): Burnett Mary, Cape York, Condamine, Cooperative Management Area, Desert Channels, Fitzroy, Burdekin, Northern Gulf, Border Rivers Maranoa-Balonne, Mackay Whitsunday, South East Queensland, South West Queensland, Southern Gulf, Wet Tropics and Torres Strait. Tables 5-8 in the Downloads tab present changes in land cover at a broad and detailed level between the two intervals, January 2010 to December 2011 and January 2014 to December 2015.

The rate at which land cover changes is relatively slow and the Dynamic Land Cover Dataset (DLCD) v2.1 dataset remains in a testing phase. As such, the information should be interpreted cautiously and with reference to the data custodians, Geoscience Australia (GA). Changes in land cover have many potential drivers, including human activities and natural phenomena. The DLCD data presented summarises many observations of the Earth's surface to provide a single dominant land cover class for each of the two-year periods selected. There will be some level of land cover change within and between each two-year layer of DLCD. This intra-period and inter-period variation should be considered when interpreting the changes reported between the two accounting periods.

In general the classification method used for land cover relied on the Enhanced Vegetation Index (EVI) time series. However, when this methodology was found to be inappropriate for certain classifications a mask (substitute data from another source) within the DLCD dataset was used to derive land cover. This affected the broad classifications 'Urban Areas & Extraction Sites', 'Rainfed Lands' and 'Irrigated Lands' and detailed classifications 'Urban Areas', 'Extraction Sites', 'Irrigated Sugar' and 'Rainfed Sugar'. As a consequence, users who wish to track the change in extent of these classes should refer to alternative data sources. See Explanatory Notes for more information. The full DLCD classification (including broad and detailed classes) is presented on the Classifications (Appendix) page.


MAIN FINDINGS

'Urban Areas & Extraction Sites' land cover

The broad 'Urban Areas & Extraction Sites' land cover represented 0.2% of land within Queensland, and covered 299,863 hectares in both 2010-2011 and 2014-2015. The largest area of 'Urban Areas & Extraction Sites' is located within the South East Queensland NRMR with 126,888 hectares. As this class was created from a mask no changes were reported.

'Trees' land cover

The broad class 'Trees' represented 42% and 37% of all land cover in Queensland in 2010-2011 and 2014-2015 respectively. Between 2010-2011 and 2014-2015, 'Trees' decreased from 72.1 million hectares to 64.3 million hectares, a percentage decrease of 11% (or 7.8 million hectares). This included 16.3 million hectares of additions and 24.1 million hectares of reductions. The South West Queensland NRMR reported the largest net decrease (2.5 million hectares) of 'Trees', followed by the Southern Gulf NRMR (2.4 million hectares). Where 'Trees' coverage was lost, the land cover had largely changed to 'Woody Shrubs' (4.2 million hectares) and 'Grasslands' (3.8 million hectares).

The 'Trees' land cover includes the detailed classes 'Closed Forest', 'Open Forest', 'Woodland' and 'Open Woodland'. 'Open Woodland' was the only land cover in the 'Trees' class to have a net increase between 2010-2011 and 2014-2015 (2.8 million hectares). In contrast, net decreases occurred in the 'Woodland' (6.4 million hectares), 'Open Forest' (3.6 million hectares) and 'Closed Forest' (653,794 hectares) land cover classes. Considerable net change also occurred between the four 'Trees' classes, including 5.9 million hectares of land converting from 'Woodland' to 'Open Woodland'.

'Woody Shrubs' and 'Grasslands' land covers

'Woody Shrubs' accounted for 4% and 11% of all land cover in Queensland for 2010-2011 and 2014-2015 respectively. 'Woody Shrubs' land cover increased between 2010-2011 and 2014-2015 from 7.3 million hectares to 18.3 million hectares, which represented an increase of 152% (or 11.0 million hectares). This included 14.6 million hectares of additions and 3.5 million hectares of reductions. The largest change to 'Woody Shrubs' came from 'Grasslands' with an increase of 6.7 million hectares. The South West Queensland NRMR reported the largest net increase of 'Woody Shrubs' with 5.4 million hectares.

The 'Woody Shrubs' land cover includes the detailed classes 'Dense Shrubland' and 'Open Shrubland', which both reported net increases between 2010-2011 and 2014-2015. 'Dense Shrubland' increased from 3.9 million hectares to 10.8 million hectares and 'Open Shrubland' increased from 3.4 million hectares to 7.5 million hectares across the accounting period.

'Grasslands' represented 49% and 48% of all land cover in 2010-2011 and 2014-2015 respectively, the largest area of all land cover classes within Queensland. Between 2010-2011 and 2014-2015 'Grasslands' decreased from 84.6 million hectares to 82.3 million hectares (a decrease of 2.6%). This decrease included 31.9 million hectares of additions and 34.2 million hectares of reductions, which highlights the fluctuation of this broad land cover class. The largest area of 'Grasslands' was found in the Desert Channels NRMR region, which contained 40.5 million hectares in 2010-2011 and 38.7 million hectares in 2014-2015.

The 'Grasslands' land cover includes the detailed classes 'Closed Tussock Grassland', 'Alpine Grasses', 'Open Hummock Grassland', 'Open Tussock Grassland' and 'Sparse Vegetation'. 'Sparse Vegetation' was the greatest contributor to this aggregated land cover with 35.3 million and 53.3 million hectares in 2010-2011 and 2014-2015 respectively.

'Irrigated Lands' and 'Rainfed Lands' land covers

'Irrigated Lands' represented 0.3% of all land cover in Queensland for both reference periods. Between 2010-2011 and 2014-2015, 'Irrigated Lands' decreased by 6.7% from 581,744 hectares to 542,675 hectares. This included 49,206 hectares of additions and 88,275 hectares of reductions. The net decrease to 'Irrigated Lands' between 2010-2011 and 2014-2015 was largely due to a loss of 40,669 hectares which was reclassified as 'Rainfed Lands'. The Burnett Mary NRMR showed the greatest net decrease of 'Irrigated Lands' with 12,656 hectares.

The 'Irrigated Lands' land cover includes the detailed classes 'Irrigated Cropping', 'Irrigated Pasture' and 'Irrigated Sugar'. 'Irrigated Cropping' was the largest contributor to the 'Irrigated Lands' class and decreased from 343,400 hectares to 302,944 hectares between 2010-2011 and 2014-2015. This overall decrease in 'Irrigated Cropping' land area was driven by net changes to 'Rainfed Pasture' (27,825 hectares) and 'Rainfed Cropping' (12,775 hectares).

In 2010-2011 and 2014-2015 'Rainfed Lands' represented 3.3% and 3.1% respectively, of all land cover in Queensland. 'Rainfed Lands' changed from 5.6 million hectares to 5.4 million hectares, with a net decrease of 271,319 hectares (or 4.8%). This included 395,531 hectares of additions and 666,850 hectares of reductions. The largest change in 'Rainfed Lands' was largely due to a net decrease of 183,550 hectares to the 'Grasslands' land cover. The Fitzroy NRMR reported the largest changes to 'Rainfed Lands' with a net decrease of 135,644 hectares.

The 'Rainfed Lands' land cover includes the detailed classes 'Rainfed Cropping', 'Rainfed Pasture' and 'Rainfed Sugar'. 'Rainfed Pasture' accounted for the majority of land in the aggregated 'Rainfed Lands' land cover class, with 4.2 million hectares in 2010-2011 and 4.0 million hectares in 2014-2015. 'Rainfed Pasture' experienced a net loss between these periods of 201,738 hectares which was largely driven by net changes to 'Woodland' (216,231 hectares).

'Waterbodies' and 'Wetlands' land cover

In 2014-2015 the 'Waterbodies' land cover represented 0.5% of all land cover in Queensland, while 'Wetlands' represented 0.3%. Between 2010-2011 and 2014-2015, the 'Waterbodies' land cover decreased from 1.1 million hectares to 888,625 hectares, while 'Wetlands' also decreased, from 1.1 million hectares to 563,281 hectares. These decreases in Waterbodies and Wetlands land cover are likely related to an overall decrease in total rainfall across these same accounting periods, as reported by the Bureau of Meteorology.

The overall decrease in 'Waterbodies' included 76,881 hectares of additions and 268,113 hectares of reductions. The majority of this decrease was a result of changes from 'Waterbodies' to 'Grasslands' (154,494 hectares) and 'Woody Shrubs' (41,663 hectares). Similarly the large decline in 'Wetlands' (48%) included 80,175 hectares of additions and 592,519 hectares of reductions. Over the accounting period, the biggest decrease in 'Wetlands' was to 'Grasslands' (313,819 hectares), followed by 'Woody Shrubs' (104,638 hectares). For both 'Waterbodies' and 'Wetlands' the biggest changes occurred in the Desert Channels NRMR. 'Waterbodies' decreased by 125,713 hectares and 'Wetlands' decreased by 324,256 hectares.