Norton, Brien E.

Russell, Peter J.

Thomas, Phil W. E.

Watson, Ian W.

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings 21st International Grassland Congress / 8th International Rangeland Congress Changes in Range Condition in the Arid Shrublands of Western Australia: Application of Spatialand Temporal Analysis to Long‐Term Monitoring Data Peter J. Russell Curtin University, Australia Ian W. Watson CSIRO, Australia Phil W. E. Thomas Department of Agriculture and Food, Australia Brien E. Norton Curtin University, Australia Follow this and additional works at: https://uknowledge.uky.edu/igc  Part of the Plant Sciences Commons, and the Soil Science Commons This document is available at https://uknowledge.uky.edu/igc/21/4-1/32 The 21st International Grassland Congress / 8th International Rangeland Congress took place in Hohhot, China from June 29 through July 5, 2008. Proceedings edited by Organizing Committee of 2008 IGC/IRC Conference Published by Guangdong People's Publishing House This Event is brought to you for free and open access by the Plant and Soil Sciences at UKnowledge. It has been accepted for inclusion in International Grassland Congress Proceedings by an authorized administrator of UKnowledge. For more information, please contact UKnowledge@lsv.uky.edu. 瞯 ]590　 瞯 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅰ 　Grasslands/Rangelands Resources and Ecology ——— Indicators for Sustainable Use and Conservation of Grasslands/Rangelands ResourcesChanges in range condition in the arid shrublands of Western Australia : application of spatialand temporal analysis to long‐term monitoring dataPeter J Russell1 , Ian W W atson2 , Phil W E Thomas3 and Brien E Norton11 Curtin University , Locked Bag ２２ , Kalgoorlie , Western Australia ; E‐mail : p .russell ＠ cmae .curtin .edu .au ; ２ CSIRO ,Townsville , Queensland ; ３ Department of Agriculture and Food , Perth , Western AustraliaKey words :monitoring , grazing , range condition , shrublands , GIS , WARMSIntroduction The effects of climate , herbivore grazing , fire and other natural and anthropogenic disturbances are reflected bychanges in range condition , driven by changes in soil and vegetation condition . When range condition is used in an ecologicalcontext , an improving trend implies an improvement in ecological or ecosystem integrity . In contrast , a declining trend impliesa reduction in integrity , otherwise known as natural resource degradation . This study integrated soil and vegetation conditionattributes into a quantitative index of range condition and mapped its variation through time across the shrublands of WesternAustralia , covering a total area of approximately ７６０ ,０００ km２ .Methods and materials The analysis is based on a hierarchical suite of soil and vegetation indices derived from transect fieldmetrics acquired by the Western Australian Rangeland Monitoring System (WARMS) . WARMS is an extensive , long‐term ,ground‐based system established in １９８１ to monitor range condition change in the pastoral rangelands and is operated by theDepartment of Agriculture and Food Western Australia ( DAFWA ) . By the end of ２００６ , ９８０ sites located on ３７７ pastoralleases existed at an average density of one site per ７７ ,７８０ hectares of pastoral shrubland . Data collection protocol has remainedessentially unchanged since １９９２ and new data is captured at each site on a ５‐year cycle( Watson , Novelly & Thomas ２００７ ) .The Shrubland Range Condition ( SRC) index and sub‐indices were partitioned into ４‐year time‐slices based on data capture dateand then spatio‐temporal maps showing relative range condition for each time‐slice and change between time‐slices , eachclassified into five classes , were produced using Geographic Information System ( GIS ) techniques . Change maps utilised anInverse Distance Weighted ( IDW) analysis technique to identify clusters of sites displaying similar change behaviour .Results and discussion Local , regional and shrubland‐wide patterns of change are evident . In the northwest of the shrublands ,change in range condition is generally more spatially and temporally variable , greater in magnitude and involves larger clustersof sites compared to areas in the southeast . Many clusters of sites show alternate improvement and decline between time‐sliceswhilst several clusters in the Ashburton and Murchison catchments continued to decline over the last １５ years or so . For mostsites showing negative change , causal agent ( s ) of change , usually high grazing pressure but also fire and flood , could beinferred . Only two clusters of sites , located in the upper reaches of the Gascoyne River , steadily improved over the sameperiod . Most sites are in �Fair" condition in the Goldfields region and in �Poor" condition in the Nullarbor region , however ,the concern is that most of these sites in both regions also showed little or no change in range condition , despite a １０‐yearsequence of average or above average rainfall throughout much of the shrublands . The ecological response to grazing and otherdisturbances across the shrublands , reflected by change in the SRC index , appears to be related , at least in part , to drainagetype . In general , monitoring sites located in endorheic and arheic basins exhibit less change in range condition compared to siteslocated in exorheic catchments . This is interpreted to reflect differences in rates of incision and soil erosion fundamentallyrelated to ultimate and local drainage base levels . The regional insight provided by this study supports local field observationsmade by Pringle and Tinley (２００３ ) of certain critical hydrogeomorphic processes involved in land degradation .Conclusions The combination of hierarchical index framework , use of time‐slices and GIS mapping techniques provides a potentanalysis platform for the elucidation of spatial and temporal change in range condition or ecological integrity at WARMS sites .The study has shown that natural resources in exorheic catchments are more susceptible to degradation . In this particularcatchment type , but also throughout the endorheic and arheic basins , much more ecologically benign land use practices must beimplemented to reverse range degradation in the shrublands of Western Australia .ReferencesPringle , H . J . R . & Tinley , K . ( ２００３ ) , �Are we overlooking critical geomorphic determinants of landscape changeinAustralian rangelands ?�Ecological Management and Restoration , vol . ４ , no . ３ , pp . １８０‐１８６ .Watson , I . W . , Novelly , P . E . & Thomas , P . W . E . ( ２００７ ) ,�Monitoring changes in pastoral rangelands‐the WesternAustralian Rangeland Monitoring System (WARMS)�, The Rangeland Journal , vol . ２９ , no . ２ , pp . １９１‐２０５ .

Changes in Range Condition in the Arid Shrublands of Western Australia: Application of Spatialand Temporal Analysis to Long‐Term Monitoring Data

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Changes in Range Condition in the Arid Shrublands of Western Australia: Application of Spatialand Temporal Analysis to Long‐Term Monitoring Data

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