Estimating woody vegetation cover in arid and semi-arid rangelands

Measuring woody vegetation cover (WVC) is an essential part of ecological monitoring in rangelands. While continental-scale products that map vegetation cover from satellite remote sensing are available, it is uncertain whether these products are well suited for analyses at the sub-catchment and pro...

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Main Authors: Jaume Ruscalleda-Alvarez, Gerald F.M. Page, Katherine Zdunic, Suzanne M. Prober
Format: Article
Language:English
Published: Elsevier 2025-08-01
Series:Ecological Indicators
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Online Access:http://www.sciencedirect.com/science/article/pii/S1470160X25006715
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author Jaume Ruscalleda-Alvarez
Gerald F.M. Page
Katherine Zdunic
Suzanne M. Prober
author_facet Jaume Ruscalleda-Alvarez
Gerald F.M. Page
Katherine Zdunic
Suzanne M. Prober
author_sort Jaume Ruscalleda-Alvarez
collection DOAJ
description Measuring woody vegetation cover (WVC) is an essential part of ecological monitoring in rangelands. While continental-scale products that map vegetation cover from satellite remote sensing are available, it is uncertain whether these products are well suited for analyses at the sub-catchment and property scale. We evaluated a novel approach to regional-scale mapping of WVC in the southern rangelands of Western Australia, with focus on two ex-pastoral properties. We used random forest regression and a segmented linear regression trained on high resolution satellite imagery and applied to Landsat imagery, and validated them using an independent, high-resolution and multi-year dataset. We compared the performance of our models to that of a broadly used continental-scale fractional cover (FC) dataset available for Australia. We tested the sensitivity of our locally calibrated WVC models to monitor vegetation recovery following chain-clearing in 1973 compared with an adjacent un-cleared patch. Both locally calibrated models were five times more accurate at estimating WVC than the national-scale FC data. The cleared and uncleared plots showed expected trends in WVC (increasing and homeostatic, respectively) using both locally trained models. This study demonstrated that a segmented linear model based on a spectral index can reliably predict WVC at a pastoral-property scale over a multi-annual period. In contrast, continental scale products, while valid to track trends in WVC at larger scales, should be used with caution when guiding local management. The construction of a national product that consolidates regionally-calibrated models of WVC would provide more accurate local information and aggregated national trends.
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spelling doaj-art-e34f47ac3b3d4dd080d9cd18267a622b2025-08-20T02:43:25ZengElsevierEcological Indicators1470-160X2025-08-0117711374110.1016/j.ecolind.2025.113741Estimating woody vegetation cover in arid and semi-arid rangelandsJaume Ruscalleda-Alvarez0Gerald F.M. Page1Katherine Zdunic2Suzanne M. Prober3Commonwealth Scientific and Industrial Research Organisation, 7 Conlon Street, Waterford 6152 Western Australia, Australia; Department of Biodiversity, Conservation and Attractions, 17 Dick Perry Avenue, Kensington 6151 Western Australia, Australia; Corresponding author.School of Environmental and Conservation Sciences, Murdoch University, 90 South St, Murdoch 6150 Western Australia, AustraliaDepartment of Biodiversity, Conservation and Attractions, 17 Dick Perry Avenue, Kensington 6151 Western Australia, AustraliaCommonwealth Scientific and Industrial Research Organisation, 2-40 Clunies Ross Street, Acton, ACT 2601, AustraliaMeasuring woody vegetation cover (WVC) is an essential part of ecological monitoring in rangelands. While continental-scale products that map vegetation cover from satellite remote sensing are available, it is uncertain whether these products are well suited for analyses at the sub-catchment and property scale. We evaluated a novel approach to regional-scale mapping of WVC in the southern rangelands of Western Australia, with focus on two ex-pastoral properties. We used random forest regression and a segmented linear regression trained on high resolution satellite imagery and applied to Landsat imagery, and validated them using an independent, high-resolution and multi-year dataset. We compared the performance of our models to that of a broadly used continental-scale fractional cover (FC) dataset available for Australia. We tested the sensitivity of our locally calibrated WVC models to monitor vegetation recovery following chain-clearing in 1973 compared with an adjacent un-cleared patch. Both locally calibrated models were five times more accurate at estimating WVC than the national-scale FC data. The cleared and uncleared plots showed expected trends in WVC (increasing and homeostatic, respectively) using both locally trained models. This study demonstrated that a segmented linear model based on a spectral index can reliably predict WVC at a pastoral-property scale over a multi-annual period. In contrast, continental scale products, while valid to track trends in WVC at larger scales, should be used with caution when guiding local management. The construction of a national product that consolidates regionally-calibrated models of WVC would provide more accurate local information and aggregated national trends.http://www.sciencedirect.com/science/article/pii/S1470160X25006715Rangeland ecological conditionWoody vegetation coverRemote sensing
spellingShingle Jaume Ruscalleda-Alvarez
Gerald F.M. Page
Katherine Zdunic
Suzanne M. Prober
Estimating woody vegetation cover in arid and semi-arid rangelands
Ecological Indicators
Rangeland ecological condition
Woody vegetation cover
Remote sensing
title Estimating woody vegetation cover in arid and semi-arid rangelands
title_full Estimating woody vegetation cover in arid and semi-arid rangelands
title_fullStr Estimating woody vegetation cover in arid and semi-arid rangelands
title_full_unstemmed Estimating woody vegetation cover in arid and semi-arid rangelands
title_short Estimating woody vegetation cover in arid and semi-arid rangelands
title_sort estimating woody vegetation cover in arid and semi arid rangelands
topic Rangeland ecological condition
Woody vegetation cover
Remote sensing
url http://www.sciencedirect.com/science/article/pii/S1470160X25006715
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