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International Journal of Wildland Fire International Journal of Wildland Fire Society
Journal of the International Association of Wildland Fire
RESEARCH ARTICLE

Seed tolerance to heating is better predicted by seed dormancy than by habitat type in Neotropical savanna grasses

Desirée M. Ramos A E G , Ana B. S. Liaffa B , Pedro Diniz C , Cássia B. R. Munhoz A , Mark K. J. Ooi D E , Fabian Borghetti A and José F. M. Valls A F
+ Author Affiliations
- Author Affiliations

A Programa de Pós-Graduação em Botânica, Instituto de Ciências Biológicas, Universidade de Brasília, 70910-900, Brasília, Distrito Federal, Brazil.

B Departamento de Engenharia Florestal, Faculdade de Tecnologia, Universidade de Brasília, 70910-900, Brasília, Distrito Federal, Brazil.

C Programa de Pós-Graduacão em Ecologia, Universidade de Brasília, Brasília, DF 70910-900, Brazil.

D Centre for Sustainable Ecosystem Solutions, School of Biological Sciences, University of Wollongong, Wollongong, NSW 2522, Australia.

E Centre for Ecosystem Science, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia.

F Empresa Brasileira de Pesquisa Agropecuária, Embrapa, Embrapa Recursos Genéticos e Biotecnologia, Parque Estação Biológica – PqEB s/n°, 70770-917, Brasília, Distrito Federal, Brazil.

G Corresponding author. Email: desibio@gmail.com

International Journal of Wildland Fire 25(12) 1273-1280 https://doi.org/10.1071/WF16085
Submitted: 11 May 2016  Accepted: 13 September 2016   Published: 25 November 2016

Abstract

Open savannas and wet grasslands are present under the same seasonal macro-climate in central Brazil. However, in open savannas, temperatures during fires are higher than in wet grasslands. Grasses dominate both ecosystems and exhibit large variation in seed dormancy. We hypothesise that seeds of grass species from open savannas are more tolerant to heating than those of wet grasslands. Also, assuming that dormant seeds remain longer in the soil than non-dormant seeds – thus being more likely to burn – we expect that dormant seeds are more tolerant to heating than non-dormant seeds. We tested the effects of heating at 80 and 110°C for 2.5 and 5.0 min on the survival of seeds of 14 species, seven from each community, containing dormant and non-dormant species. Seeds of most species survived at 80°C, but seeds from open savannas maintained greater survival for 5 min than seeds from wet grasslands. Seeds of most species died at 110°C, but dormant seeds survived more than non-dormant seeds. We conclude that species with seed dormancy experience selection for covarying characteristics that allow tolerance to heating in hotter fires. Our findings suggest that both seed dormancy and habitat-specific fire temperatures may contribute to the evolution of seed fire tolerance in Neotropical savannas.

Additional keywords: Cerrado, fire, habitat seasonality, heat shock, open savanna, seed dormancy, wet grassland.


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