Shrub Recruitment Response to Intensity and Season of Fire in a Semi-Arid Woodland

Hodgkinson, K. C.

doi:10.2307/2404113

Cited by 79 publications

(56 citation statements)

References 14 publications

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“…While a strong seasonal pattern of rainfall does not occur in south-eastern Australia, time periods with adequate soil moisture to allow seedling germination and emergence are much more common in the cooler seasons (Bradstock and Bedward 1992). Seeds with released physical dormancy germinate, independently of season, as soon as moisture conditions are suitable (Hodgkinson 1991;Bell 1999). Therefore, there is also the potential for an adaptive advantage in these non-seasonal rainfall habitats.…”

Section: Discussionmentioning

confidence: 99%

“…Rupture of dormancy several weeks or months after fire could be an advantage avoiding unsuitable conditions in the immediate postfire period, which could limit the success of seedling establishment or survival (Frazer and Davis 1988;Carrington 1999;De Luis et al 2005). Hodgkinson (1991) found in semiarid woodland with no seasonal rainfall pattern in inner south-eastern Australia higher germination and survival rates for leguminous species regenerated after spring and summer fires than in winter fires.…”

Section: Discussionmentioning

confidence: 99%

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Effects of soil temperature regimes after fire on seed dormancy and germination in six Australian Fabaceae species

et al. 2010

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M. (2010). Effects of soil temperature regimes after fire on seed dormancy and germination in six Australian Fabaceae species. Australian Journal of Botany, 58 (7), 539-545.Effects of soil temperature regimes after fire on seed dormancy and germination in six Australian Fabaceae species AbstractIn addition to direct fire cues such as heat, smoke and charred wood, the passage of fire leads indirectly to changes in environmental conditions which may be able to break physical dormancy in hard-coated seeds. After a fire, the open canopy and the burnt material lying on the surface alter the thermal properties of the soil, resulting in elevated soil temperatures for long periods of time. We simulated daily temperature regimes experienced at different depths of soil profile after a summer fire. Our aim was to determine whether these temperature regimes and the duration of exposure (5, 15 and 30 days) play an important role breaking physical seed dormancy in six legumes from south-eastern Australia. Our results showed that simulated temperature regimes break seed dormancy. This effect is specially pronounced at temperatures that are expected to occur near the soil surface (0-2 cm depth). The duration of exposure interacts with temperature to break dormancy, with the highest germination rates reached after the longest duration and highest temperatures. However, the germination response varied among species. Therefore, this indirect post-fire cue could play a role in the regeneration of plant communities, and could stimulate seedling emergence independent of direct fire cues as well as in interaction with direct cues. © 2010 CSIRO. Abstract. In addition to direct fire cues such as heat, smoke and charred wood, the passage of fire leads indirectly to changes in environmental conditions which may be able to break physical dormancy in hard-coated seeds. After a fire, the open canopy and the burnt material lying on the surface alter the thermal properties of the soil, resulting in elevated soil temperatures for long periods of time. We simulated daily temperature regimes experienced at different depths of soil profile after a summer fire. Our aim was to determine whether these temperature regimes and the duration of exposure (5, 15 and 30 days) play an important role breaking physical seed dormancy in six legumes from south-eastern Australia. Our results showed that simulated temperature regimes break seed dormancy. This effect is specially pronounced at temperatures that are expected to occur near the soil surface (0-2 cm depth). The duration of exposure interacts with temperature to break dormancy, with the highest germination rates reached after the longest duration and highest temperatures. However, the germination response varied among species. Therefore, this indirect post-fire cue could play a role in the regeneration of plant communities, and could stimulate seedling emergence independent of direct fire cues as well as in interaction with direct cues.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Effects of soil temperature regimes after fire on seed dormancy and germination in six Australian Fabaceae species

et al. 2010

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“…The removal of fire in vegetation communities that evolved with fire can be both positive and negative (Noble, 1989;Bailey, 1988;Hodgkinson, 1991). Fire enhanced the germination of two of the seven principal shrub species in a semiarid shrub-invaded woodland in eastern Australia (Hodgkinson, 1991).…”

Section: Origin Of Bush Encroachment In Botswanamentioning

confidence: 99%

“…Fire enhanced the germination of two of the seven principal shrub species in a semiarid shrub-invaded woodland in eastern Australia (Hodgkinson, 1991). In semi-arid rangelands where rainfall is very variable in time and space, it is likely that fire fuel availability will differ from patch to patch.…”

Section: Origin Of Bush Encroachment In Botswanamentioning

confidence: 99%

More woody plants? the status of bush encroachment in Botswana’s grazing areas

Moleele

Ringrose

Matheson³

et al. 2002

Journal of Environmental Management

163

136

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“…Plants of these woodlands are able to withstand persistent droughts as well as periodic occurrence of fire. The shrubs, trees and perennial grasses regenerate after fire by resprouting and/or by germination of soil-borne seed (Hodgkinson and Griffin 1982;Hodgkinson 1991).…”

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confidence: 99%

Water relations and growth of shrubs before and after fire in a semi-arid woodland

Hodgkinson

1992

Oecologia

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Plant water relations and shoot growth rate of shrubs resprouting after fire or unburnt were measured in a semi-arid poplar box (Eucalyptus populnea) shrub woodland of eastern Australia. In vegetation unburnt for about 60 years, the dawn xylem water potential (ψ) of the dominant shrub species was about-1.0 MPa when the soil was wet and-8.0 MPa when the soil was very dry. At any one time, the dominant shrub species,Eremophila mitchellii, E. sturtii, Geijera parviflora andCassia nemophila, were similar in ψ butAcacia aneura andDodonaea viscosa were consistently higher in ψ than this group when the soil was moist and lower when the soil was dry. The dominant tree species,Eucalyptus populnea andE. intertexta, appeared to have access to additional water beneath the hardpan which is located 60-80 cm below the surface. When shrubs were under extreme water stress (ψ of-8 MPa), the trees had a ψ of-3 to-3.6 MPa. Following a fire, both ψ and leaf stomatal conductance (g ) of resprouting shrubs were higher for about 5 years than comparable-aged unburnt vegetation, with relative differences in ψ increasing with drought stress. Elongation rate of resprouts was positively linked to prefire shrub height in 3 of 4 species. However, shrubs resprouting after high intensity fires had substantially higher rates of shoot elongation than after low intensity fires which were in turn higher than for foliar expansion of unburnt shrubs. It is concluded that the growth rate of resprouting shrubs is primarily determined by physiological/ morphological factors associated with plant size but is also assisted by greater availability of water and possibly nutrients for a period after fire.

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Shrub Recruitment Response to Intensity and Season of Fire in a Semi-Arid Woodland

Cited by 79 publications

References 14 publications

Effects of soil temperature regimes after fire on seed dormancy and germination in six Australian Fabaceae species

Effects of soil temperature regimes after fire on seed dormancy and germination in six Australian Fabaceae species

More woody plants? the status of bush encroachment in Botswana’s grazing areas

Water relations and growth of shrubs before and after fire in a semi-arid woodland

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