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

@article{Ooi2014TemperatureTO,
  title={Temperature thresholds of physically dormant seeds and plant functional response to fire: variation among species and relative impact of climate change},
  author={Mark K. J. Ooi and Andrew J. Denham and Victor M. Santana and Tony D. Auld},
  journal={Ecology and Evolution},
  year={2014},
  volume={4},
  pages={656 - 671}
}
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… 

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References

SHOWING 1-10 OF 88 REFERENCES

Projected soil temperature increase and seed dormancy response along an altitudinal gradient: implications for seed bank persistence under climate change

TLDR
It is suggested that parental climate is the key selective force determining dormancy-breaking threshold temperatures, ensuring inter-fire seed bank persistence and producing conditions that provide a mechanism for seed bank compromise.

Tanned or Burned: The Role of Fire in Shaping Physical Seed Dormancy

TLDR
It is suggested that in Mediterranean species with physical dormancy, the temperature thresholds necessary to trigger seed germination are better explained as a response to fire than as an response to summer temperatures.

Seed bank persistence and climate change

  • M. Ooi
  • Environmental Science
    Seed Science Research
  • 2012
Abstract The strong mechanistic relationship between climatic factors and seed dormancy and germination suggests that forecast climatic changes will significantly affect seed bank persistence. This

Climate change and plant regeneration from seed

TLDR
Increased research in understudied ecosystems, on key issues related to seed ecology, and on evolution of seed traits in nonweedy species is needed to more fully comprehend and plan for plant responses to global warming.

Distinguishing between persistence and dormancy in soil seed banks of three shrub species from fire-prone southeastern Australia

TLDR
Long-lived seed banks are an important trait of plants from fire-prone communities, but cues observed to promote germination in situ are not necessarily the ones that break dormancy.

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

TLDR
Simulation of temperature regimes after a summer fire showed that simulated temperature regimes break seed dormancy, and the highest germination rates reached after the longest duration and highest temperatures, however, the germination response varied among species.

Patterns of seed longevity and dormancy in obligate seeding legumes of box‐ironbark forests, south‐eastern Australia

TLDR
Variation in the dormancy and longevity patterns observed in these obligate seeder legumes suggests two strategies: (i) releasing a portion of soil-stored seed from dormancy during the inter-fire period to permit inter- fire recruitment; and (ii) retaining most soil-Stored seed as dormant during the Inter-fire interval, both of which represent potential weaknesses under a long fire interval regime.

Climate change and bet‐hedging: interactions between increased soil temperatures and seed bank persistence

In order to predict the long‐term consequences of climate change, it is necessary to link future environmental changes to mechanisms that control plant population processes. This information can then

Clarifying the role of fire heat and daily temperature fluctuations as germination cues for Mediterranean Basin obligate seeders.

TLDR
The relevance of depleting vegetation (and subsequent daily temperature fluctuation in summer) suggests that studies focusing on lower temperature thresholds for breaking seed dormancy are required and supports the hypothesis that the seeding capacity in Mediterranean Basin obligate seeders may have evolved as a response to a wide range of disturbances, and not exclusively to fire.

Soil temperatures during autumn prescribed burning: implications for the germination of fire responsive species?

Prescribed fire is a widely applied management tool in native forests. There have been concerns raised about the ecological impacts of prescribed fire on native flora. One aspect of the debate is the
...