Mapping and Spatial Analysis of Land Cover Dynamics of Threatened Grassland Ecosystems in the Condamine River Catchment

Alcorn, Matthew (2017) Mapping and Spatial Analysis of Land Cover Dynamics of Threatened Grassland Ecosystems in the Condamine River Catchment. [USQ Project]


Since early pastoralists first walked the virgin lands of the Darling Downs the lands have been used extensively for farming purposes. What started out as widespread sheep and cattle grazing eventually turned into equally widespread agricultural cropland, and to this day the region of the Condamine catchment is very much dominated by these land uses. In this respect, much of the original land cover has since changed, and in the instance of the native Bluegrass grasslands of the Condamine catchment, this has happened quite drastically.

The aim of this study was to quantify the change in coverage of RE’s 11.3.21 and 11.3.24, and then determine the prime factors to their clearance in regard to land uses, land cover and land characteristics. This was accomplished through processing, comparison and analysis of available spatial data of the study area in the form of satellite imagery, regional ecosystem maps, land use data and road and drainage networks.

Landsat 5 and Landsat 8 imagery were utilised in mapping the grasslands using remote sensing, and the results were verified using an accuracy assessment, while assessing the validity of the method. The satellite imagery was acquired in the form of a single images from 1991 and 2017 and classified using a post-classification procedure, and were then compared to produce change statistics.

The study confirms that the native grasslands have not only been severely reduced, but heavily fragmented to the point that very few fragments can be considered healthy nor be able to support other species. The majority of these fragments exist as thin corridors alongside roads and on river embankments, while others exist as degraded pastures. However, data suggests that some patches may be under protection and/or rehabilitation, with a net rise in coverage for the region.

It was found that agricultural land uses were the predominant land use over the previous extent of the native grasslands, with grazing pastures having mostly been converted in this region. This is due to the conditions for growth of the grasslands are also ideal conditions for cultivation. These conditions were those that make the Condamine plains so valuable, that being their flatness and fertility.

Lastly, the study finds that the single-date post classification procedure in the application of mapping native grasslands of southern and central Queensland is adequate if used in conjunction with other methods to confirm land covers. This procedure is not recommended solely as it is prone to spectral confusion due to the variety of spectral signatures that can be produced from grassland compositions, scarceness and varieties.

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Item Type: USQ Project
Item Status: Live Archive
Additional Information: Bachelor of Spatial Science (Honours) (Surveying)
Faculty/School / Institute/Centre: Historic - Faculty of Health, Engineering and Sciences - School of Civil Engineering and Surveying (1 Jul 2013 - 31 Dec 2021)
Supervisors: Apan, Armando
Date Deposited: 07 Sep 2022 03:38
Last Modified: 07 Sep 2022 03:38
Uncontrolled Keywords: mapping; spatial analysis; grassland ecosystems; threatened; Condamine River catchment

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