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Evaluation of vegetation indices for rangeland biomass estimation in the Kimberley area of Western Australia

Access Status
Open access
Authors
Mundava, Charity
Helmholz, Petra
Schut, Tom
Corner, Robert
McAtee, B.
Lamb, D.
Date
2014
Type
Conference Paper

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Citation
Mundava, C. and Helmholz, P. and Schut, T. and Corner, R. and McAtee, B. and Lamb, D. 2014. Evaluation of vegetation indices for rangeland biomass estimation in the Kimberley area of Western Australia, in Sunar, F. and Altan, O. and Taberner, M. (ed), International Society for Photogrammetry and Remote Sensing (ISPRS) Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Sep 29-Oct 2 2014, pp. 47-53. Istanbul, Turkey: International Society for Photogrammetry and Remote Sensing.
Source Title
ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume II-7
Source Conference
ISPRS Technical Commission VII Symposium
DOI
School
Department of Spatial Sciences
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This article is published under the Open Access publishing model and distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0/ Please refer to the licence to obtain terms for any further reuse or distribution of this work.

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Abstract

The objective of this paper is to test the relationships between Above Ground Biomass (AGB) and remotely sensed vegetation indices for AGB assessments in the Kimberley area in Western Australia. For 19 different sites, vegetation indices were derived from eight Landsat ETM+ scenes over a period of two years (2011–2013). The sites were divided into three groups (Open plains, Bunch grasses and Spinifex) based on similarities in dominant vegetation types. Dry and green biomass fractions were measured at these sites. Single and multiple regression relationships between vegetation indices and green and total AGB were calibrated and validated using a "leave site out" cross validation. Four tests were compared: (1) relationships between AGB and vegetation indices combining all sites; (2) separate relationships per site group; (3) multiple regressions including selected vegetation indices per site group; and (4) as in 3 but including rainfall and elevation data. Results indicate that relationships based on single vegetation indices are moderately accurate for green biomass in wide open plains covered with annual grasses. The cross-validation results for green AGB improved for a combination of indices for the Open plains and Bunch grasses sites, but not for Spinifex sites. When rainfall and elevation data are included, cross validation improved slightly with a Q2 of 0.49–0.72 for Open plains and Bunch grasses sites respectively. Cross validation results for total AGB were moderately accurate (Q2 of 0.41) for Open plains but weak or absent for other site groups despite good calibration results, indicating strong influence of site-specific factors.