Positive effect of seed size on seedling survival in fire-prone savannas of Australia, Brazil and West Africa

Abstract

All plant species face a fundamental reproductive trade-off: for a given investment in seed mass, they can produce either many small seeds or few large seeds. Whereas small seeds favour the germination of numerous seedlings, large seeds favour the survival of seedlings in the face of common stresses such as herbivory, drought or shade (Leishman et al. 2000). One mechanism explaining the better survival of large-seeded species is the seedling size effect (SSE) (Westoby et al. 1996): because seeds with large reserves result in bigger seedlings, seedlings from large-seeded species would have better access to light and/or to reliable water supply than seedlings from small-seeded species.

Non-native grass invasion suppresses forest succession

“…Additionally, seedlings with more reserves may grow faster and emerge above competing vegetation quicker, a key factor in determining seedling establishment in successional Welds (Hill et al 1995). The relative advantage of large-seeded species may be enhanced when tree seeds are competing for resources with herbaceous plants (Lahoreau et al 2006). Furthermore, this eVect may be especially pronounced when trees are in competition with a highly abundant invasive plant such as Microstegium.…”

“…For example, invasions may diVerentially aVect tree seeds, seedlings and saplings, and mature trees. Tree seedling size is an important determinant of seedling success because of diVerences in competitive ability, predation risk, and disturbance tolerance between small and large seedlings (Armstrong and Westoby 1993;Harms and Dalling 1997;Lahoreau et al 2006;Seiwa 2000). Larger seedlings or saplings have more developed root systems and may be tall enough to avoid the shading eVects of invasive plants (Lahoreau et al 2006).…”

“…Tree seedling size is an important determinant of seedling success because of diVerences in competitive ability, predation risk, and disturbance tolerance between small and large seedlings (Armstrong and Westoby 1993;Harms and Dalling 1997;Lahoreau et al 2006;Seiwa 2000). Larger seedlings or saplings have more developed root systems and may be tall enough to avoid the shading eVects of invasive plants (Lahoreau et al 2006). If a plant invader negatively aVects trees establishing from seed but saplings are unaVected, the rate of succession may be slowed and forest composition may be restricted to species already established at the time of invasion.…”

EFEITO DE ALTAS TEMPERATURAS NA GERMINAÇÃO DE SEMENTES DE Plathymenia reticulata Benth. E Dalbergia miscolobium Benth.

“…Gashaw e Michelson (2002) postularam que sementes maiores demoram mais tempo para atingir o equilíbrio com a temperatura ambiente, portanto o embrião ficará menos tempo exposto a altas temperaturas. De acordo com Lahoreau et al (2006), sementes menores teriam menor chance de sucesso no estabelecimento por apresentarem menor conteúdo de reserva. Popinigis (1985) afirmou que, para uma espécie, as sementes com menor tamanho e, ou, menor densidade possuem menor qualidade fisiológica, como observado por Sassaki e Felippe (1999) para Dalbergia miscolobuim.…”

Resilience of Amazonian forests : the roles of fire, flooding and climate

“…Before setting the experiments in January 2014, we randomly selected 10 seeds and 10 seedlings of each species to measure morphological traits that strongly correlate with resource acquisition and survival (Osunkoya et al 1994;Leishman et al 2000;Dalling and Hubbell 2002;Lahoreau et al 2006;Moles and Westoby 2006). We measured seed mass, seedling initial growth investments above and below ground (mass and length), and leaf mass (Appendix 5.2).…”