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Distribution, disturbance tolerance and conservation of Stackhousia gunnii in Tasmania

Citation

Gilfedder, LA and Kirkpatrick, JB, Distribution, disturbance tolerance and conservation of Stackhousia gunnii in Tasmania , Australian Journal of Botany, 46, (1) pp. 1-13. ISSN 0067-1924 (1998) [Refereed Article]

Abstract

Although being possibly widespread on the mainland of Australia, where it is recognised as part of the Stackhousia monogyna Labill. complex, S. gunnii Hook.f. is an endangered species in Tasmania, with only 10 known extant populations, all in the drier parts of the southern Midlands. These populations occur largely on roadsides or lightly grazed paddocks in vegetation that was originally either Themeda triandra grassland or Eucalyptus pauciflora woodland. An ordination of floristic data from sites with and without S. gunnii showed that the species occupies a floristically distinct environment. The floristic differences between stands of S. gunnii relate partly to the presence or absence of tree cover and substantially to precipitation. The groups of species that preferentially occur with S. gunnii are geophytes, non-geophytic herbs and exotic plants, while those that are concentrated elsewhere include shrubs, grasses and non-geophytic graminoids. Permanent transects were monitored over a 4-year period at seven sites with varying grazing, firing and disturbance. The number of shoots varied markedly between years in all sites, but not synchronously, even when transects were in close proximity. Although shoot numbers increased after fires occurred on several ungrazed transect lines, they decreased on one grazed line. Deep mechanical disturbance of one site resulted in a dramatic decrease in shoot numbers in the following year. However, they increased steadily over the following 2 years. Shoot emergence occurred at twice the expected rate on bare ground in all years and at all sites, and a substantial proportion of shoots was confined to this type of surface. However, shoots were also recorded in fewer numbers in grass cover, herb cover and non-vascular plant crusts. Like some other threatened plants of grassy ecosystems, S. gunnii seems to be rare because it cannot survive with heavy grazing disturbance, ploughing and fertilisation, and, at the other extreme, because it is susceptible to elimination in the absence of environmental conditions and disturbances that create bare ground.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Terrestrial Ecology
Objective Division:Environment
Objective Group:Flora, Fauna and Biodiversity
Objective Field:Flora, Fauna and Biodiversity of environments not elsewhere classified
Author:Gilfedder, LA (Ms Louise Gilfedder)
Author:Kirkpatrick, JB (Professor James Kirkpatrick)
ID Code:13812
Year Published:1998
Web of Science® Times Cited:4
Deposited By:Geography and Environmental Studies
Deposited On:1998-08-01
Last Modified:2011-08-08
Downloads:0

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