Germination of an obligate seeder (Ulex parviflorus) and consequences for wildfire management

Baeza, M. Jaime; Roy, Jacques

doi:10.1016/j.foreco.2008.05.014

Cited by 51 publications

(54 citation statements)

References 43 publications

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“…However, significant post-fire germination levels could still be reached if the litter layer was consumed and daily soil temperature regimes were enhanced. Other indirect fire cues such as the removal of canopy vegetation could increase both soil temperatures and the red : far-red light ratio, which can also promote germination in leguminous species (Baeza and Roy 2008). The combination of these factors may explain the higher than expected emergence of Acacia seedlings observed after fires studied in south-eastern Australia (Monk et al 1981;Auld 1986;Bradstock and Auld 1995).…”

Section: Discussionmentioning

confidence: 99%

“…Although few studies have investigated the effect of post-fire soil temperature regimes on native Australian species, there is evidence from other regions that have shown similar responses by members of the Fabaceae. In European heath in the Mediterranean, daily temperature cycles occurring in vegetation gaps promoted germination in the gorse Ulex parviflorus (Baeza and Roy 2008). In temperate European ecosystems, Van Assche et al (2003) found that slight seasonal changes in daily temperature fluctuations were key to breaking physical dormancy of many herbaceous legumes.…”

Section: Discussionmentioning

confidence: 99%

“…This mechanism, in addition, could play a key role in inter-fire recruitment, promoting shrub regeneration in gaps opened in the canopy vegetation. In fact, other studies in fire-prone ecosystems have contrasted these cues on seedling establishment by comparing cleared with burned plots, and observed, for example, that in California chaparral germination was more tied to direct effects of fire (Tyler 1995) whereas in other Mediterranean Basin shrublands indirect effects may increase their significance (Baeza and Roy 2008;V. M. Santana, unpubl.…”

Section: Discussionmentioning

confidence: 99%

“…Most management strategies used to control fuel load and/or maintain biodiversity in fire-prone ecosystems throughout the world are dependent on a good understanding of the relationship between direct fire cues and germination (Bradstock and Auld 1995;Baeza and Roy 2008), and for this reason, they have been widely studied both in field and laboratory experiments. In particular, the relationship between high but short-term temperature conditions experienced by seeds during fire have been tested, identifying optimal and lethal temperature thresholds for a range of species (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…In Mediterranean ecosystems, this indirect fire cue may be quite important, ensuring that a flush of germination in some hard-seeded species occurs in the wet season after summer, irrespective of the season of fire. This germination strategy has been proposed as an adaptive trait, as it avoids germination and subsequent seedling establishment failures during the dry period (Baeza and Roy 2008).…”

Section: Introductionmentioning

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%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

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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Temperature thresholds of physically dormant seeds and plant functional response to fire: variation among species and relative impact of climate change

Ooi

Denham

Santana

et al. 2014

Ecology and Evolution

137

167

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Variation in dormancy thresholds among species is rarely studied but may provide a basis to better understand the mechanisms controlling population persistence. Incorporating dormancy-breaking temperature thresholds into existing trait frameworks could improve predictions regarding seed bank persistence, and subsequently species resilience in response to fire, climate change and anthropogenic management. A key ecological strategy for many species from fire-prone ecosystems is the possession of a long-lived seed bank, ensuring recovery after fire. Physical dormancy is dominant in these ecosystems and maintaining this dormancy is directly linked to seed bank persistence. We identified a suite of seed-related factors relevant to maintaining populations in fire-prone regions for 14 co-occurring physically dormant species. We measured variation in initial levels of dormancy and then applied experimental heating treatments, based on current seasonal temperatures and those occurring during fires, to seeds of all study species. Additionally, higher seasonal temperature treatments were applied to assess response of seeds to temperatures projected under future climate scenarios. Levels of germination response and mortality were determined to assess how tightly germination response was bound to either fire or seasonal cues. Six species were found to have dormancy cues bound to temperatures that only occur during fires (80°C and above) and were grouped as having obligate pyrogenic dormancy release. The remaining species, classified as having facultative pyrogenic dormancy, had lower temperature dormancy thresholds and committed at least 30% of seeds to germinate after summer-temperature treatments. Evidence from this study supports including dormancy-breaking temperature thresholds as an attribute for identifying functional types. High temperature thresholds for breaking dormancy, found in our obligate pyrogenic group, appear to be a fire-adapted trait, while we predict that species in the facultative group are most at risk to increased seed bank decay resulting from elevated soil temperatures under projected climate change.

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Post-Fire Management of Shrublands

Calvo

Baeza

Marcos

et al. 2011

Managing Forest Ecosystems

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Germination of an obligate seeder (Ulex parviflorus) and consequences for wildfire management

Cited by 51 publications

References 43 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

Temperature thresholds of physically dormant seeds and plant functional response to fire: variation among species and relative impact of climate change

Post-Fire Management of Shrublands

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