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Environmental controls on the spatial variability of savanna productivity in the Northern Territory, Australia

Kanniah, Kasturi Devi, Beringer, Jason and Hutley, Lindsay B. (2011). Environmental controls on the spatial variability of savanna productivity in the Northern Territory, Australia. Agricultural and Forest Meteorology: an international journal,151(11):1429-1439.

Document type: Journal Article

IRMA ID 82057923xPUB64
Title Environmental controls on the spatial variability of savanna productivity in the Northern Territory, Australia
Author Kanniah, Kasturi Devi
Beringer, Jason
Hutley, Lindsay B.
Journal Name Agricultural and Forest Meteorology: an international journal
Publication Date 2011
Volume Number 151
Issue Number 11
ISSN 0168-1923   (check CDU catalogue open catalogue search in new window)
Scopus ID 2-s2.0-80052276612
Start Page 1429
End Page 1439
Total Pages 11
Place of Publication Netherlands
Publisher Elsevier BV
HERDC Category C1 - Journal Article (DIISR)
Abstract Gross Primary Productivity (GPP) is a critical measure of the health and sustainability of natural ecosystems. Understanding the magnitude, spatial patterns and processes of GPP will underpin predictions of the impact of climate change on the carbon cycle. In Australia, savannas account for one third of the terrestrial carbon stores and therefore, estimating the magnitude of savanna GPP and studying the spatial relationship between GPP and environmental determinants at the regional scale is essential in understanding ecosystem responses to increasing atmospheric CO2 concentrations and climate change. In this study we employed an integrated approach combining in situ measurements, eddy covariance based flux tower data and remote sensing techniques to examine the role of environmental drivers in controlling the spatial variation in GPP of savannas in the Northern Territory (NT), Australia. We used field based light use efficiency (LUE), regional specific meteorology and Moderate Resolution Imaging Spectro-radiometer (MODIS) based fraction of absorbed Photosynthetically Active Radiation (fPAR) data to estimate GPP. The estimated GPP agreed quite well (only a 6% error) with GPP estimated from flux tower at the Howard Springs site. The spatial pattern of GPP along the Northern Australian Tropical Transect (NATT) was calculated and showed a strong gradient in GPP from the coast (12.50°S where rainfall was 1622mmyear-1) to inland (17.73°S where mean rainfall was 643mmyear-1) with a decrease of 77%. A decreasing trend in GPP with rainfall is noticed especially at the dry end of the transect studied. However, in the wet end and middle part of the transect (e.g. dominated by different Eucalyptus species), the response of GPP to changes in rainfall is reduced. This finding suggests that the influence of rainfall on various Eucalyptus species may be dampened by biotic factors. Our results suggest that future changes in precipitation driven by climate change may affect the future distribution and dynamics of GPP in northern Australia.
Keywords Australia
Gross primary productivity
Spatial patterns
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Created: Fri, 29 Aug 2014, 17:08:27 CST by Anthony Hornby