Life histories of two arid-zone shrubs change with differences in habitat, grazing and climate

Life histories of two arid-zone shrubs change with differences in habitat, grazing and climate Journal Article

The Rangeland Journal

  • Author(s): Norman, P., Denham, R., Calvert, M. J.
  • Published: 2014
  • Volume: 36

Abstract: Shrubs are an important component of vegetation throughout the world. They are particularly significant in semiarid environments where they can dominate, driving ecosystem structure and functioning, and shaping land use. Life-history information was derived for Eremophila sturtii R.Br. and Dodonaea viscosa subsp. angustissima J.G.West, two widespread and common shrubs of semiarid eastern Australia. Plants growing under background climatic conditions took between 2 and 4 years to become established, attained the capacity to reproduce sexually at between 10 and 12 years, were in a sexually reproductive stage for between 17 and 28 years and lived an average maximum of 33–40 years. Under background climatic conditions between 70 and 80% of plants that entered the juvenile stage survived to sexual maturity while under severe drought this proportion fell to between 40 and 60%. Juvenile plants, particularly of E. sturtii, experienced the highest mortality under background conditions while, when exposed to severe drought, older plants, particularly D. viscosa subsp. angustissima in the intermediate stage, experienced the greatest increase in mortality, dying at more than twice the background rate. The high survival rates of E. sturtii and D. viscosa subsp. angustissima shown here, even under extreme drought conditions and in grazed- and ungrazed areas, help to explain why these shrub species have been observed to dominate vegetation in large areas of eastern Australia.

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Suggested Citation
Norman, P., Denham, R., Calvert, M. J., 2014, Life histories of two arid-zone shrubs change with differences in habitat, grazing and climate, Volume:36, Journal Article, viewed 09 August 2022, https://www.nintione.com.au/?p=2673.

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