Orr, David M.

Phelps, David G.

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings 21st International Grassland Congress / 8th International Rangeland Congress Plant Species Diversity as an Indicator of Sustainable Use of Astrebla Grasslands in Australia David M. Orr Department of Primary Industries and Fisheries, Australia David G. Phelps Department of Primary Industries and Fisheries, 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/21/4-1/27 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. 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅰ 　 瞯 ]585　 瞯Grasslands/Rangelands Resources and Ecology ——— Indicators for Sustainable Use and Conservation of Grasslands/Rangelands ResourcesPlant species diversity as an indicator of sustainable use of Astrebla grasslands in AustraliaD . M . Orr and D . G . PhelpsDep t . Primary Industries and Fisheries , PO Box 6014 , Rockhamp ton Mail Centre , Queensland 4702 , A ustralia . E‐mail :dav id .orr＠ dp i .qld .gov .auKey words : A strebla grassland , plant species diversity , sustainable useIntroduction A preliminary study of plant species diversity in a long term grazing study indicated that diversity was impacted bygrazing pressure : species diversity was highest at the lowest grazing pressure and lowest at both the highest grazing pressureand in exclosure ( Orr and Phelps ２００３) . This paper presents further results from the continuing diversity study and discussesthese results in terms of sustainable use in A strebla grasslands .Materials and methods A grazing study incorporating ６ grazing treatments was established in A strebla grassland near JuliaCreek , Australia in １９８４ and remains current in ２００７ . The climate is semi arid with mean annual rainfall of ４５８ mm with ８５％falling in summer ( October‐March) . T reatments are unreplicated paddocks with sheep numbers adjusted annually in autumn toconsume ０ , １０ , ２０ , ３０ , ５０ and ８０％ of the end of summer available forage . Plant species was determined in ２００１ and ２００４ bygerminating seed within soil samples collected within a ６０ x ６０ metre grid using a Geographic Positioning System . Each samplecomprised ４ individual cores of ５ cm diameter to ５ cm depth ( Orr and Phelps ２００３) . A total of １６ , １６２ , ６９ , ４９ , ３６ and ２０ soilsamples were collected from the ０ , １０ , ２０ , ３０ , ５０ and ８０％ treatments respectively .Results and discussion The ２００１ sampling occurred af ter ３ consecutive summers of above average whilst the ２００４ samplingoccurred af ter ２ consecutive summers of below average rainfall . Despite this , the overall pattern of diversity was similar withthe highest number of species recorded under the lightest grazing pressure ( Figure １ ) . High species numbers at the lightestutilisation was due mainly to the high number of forb species . This high diversity at light utilisation was dominated by palatablespecies including the native legumes Glycine f alcata and Rhynchosia minima .Figure 1 Number o f grasses and f orb species p resent in Astrebla grassland in 2001 and 2004 .Phelps et al . ( this volume) report ４０‐５０％ of the Astrebla grasslands as being in �poor" condition following ７ years ofdrought , based on rapid assessment of pasture , soil and woodland condition . The main indicator of this poor condition was lowdensity of live A strebla spp . tussocks . The data on species diversity presented in the current paper provide evidence of theuseful role of soil seed bank analyses to assess sustainable use in A strebla grasslands .Conclusions High forb species diversity , especially of more palatable species , is indicative of sustainable use in A streblagrasslands .ReferencesOrr , D . M . and Phelps , D . G . ( ２００３) . Plant species diversity in A strebla spp . grassland following １８ years of sheep grazing .Proc . VII th . International Rangelands Congress , Durban , pp . ２５６‐２５８ .Phelps , D . G . , Orr , D . M . , Houston , I . W . , Rolfe , L . and Silcock , J . ( this volume) Decline in land condition in A streblagrassland during prolonged drought in Australia .30 □ 2001 Grasses rn Cl) 25 IZI 2001 Forbs (.) ~ 20 ■ 2004 Grasses rn .... 0 15 ... Cl) 10 .c E :::I 5 z 0 0 10 20 30 50 80 Utilisation(%) 

Plant Species Diversity as an Indicator of Sustainable Use of \u3cem\u3eAstrebla\u3c/em\u3e Grasslands in Australia

https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=2687&amp;context=igc

Plant Species Diversity as an Indicator of Sustainable Use of \u3cem\u3eAstrebla\u3c/em\u3e Grasslands in Australia

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