Demography and life history of two rattan species, Eremospatha macrocarpa and Laccosperma secundiflorum, in Côte d'Ivoire

Abstract

Abstract:Two rattans species were studied in Côte d'Ivoire using a stage-classified matrix model to compare their demography and life histories. Respectively 854 and 1009 genets ofEremospatha macrocarpa(pleonanthic) andLaccosperma secundiflorum(hapaxanthic) were censused every 6 mo over 18 mo. The population growth rates ofE. macrocarpa(λ = 0.979) andL. secundiflorum(λ = 0.959) were not significantly different from 1. This indicates that the populations were close to equilibrium. However, the difference between the stable stage distributions and the observed distributions indicated temporal variation in vital rates. Elasticity analysis showed that growth and fecundity had lower contributions to λ than the survival rates for the two species. A Life Table Response Experiment revealed that the survival of the first juvenile stage (all stems < 6 m in length), fecundity, growth of the second juvenile stage (at least one stem > 6 m in length) and adult (reproductive) survival highly contribute to the differences between the demography of the two species. Reproduction is postponed longer forL. secundiflorumthan forE. macrocarpaand the mean remaining life span for adult genets is shorter forL. secundiflorumthan forE. macrocarpa. Finally, our results suggest the existence of two trade-offs within reproduction which suggest that, although the two species have different demographic features, the λ of their populations are not significantly different from 1.

Demographic processes limit upward altitudinal range expansion in a threatened tropical palm

“…In addi- The stasis of later ontogenetic stages (immature and reproductive individuals; Figure 3) was the demographic parameter with the greatest effect on λ in both E. edulis populations. This finding is in accordance with previous studies on long-lived plant species such as palms (Franco & Silvertown, 2004;Kouassi, Barot, Gignoux, & Bi, 2008;Portela, Bruna, & Santos, 2010;Sampaio & Scariot, 2010).…”

“…The stasis of later ontogenetic stages (immature and reproductive individuals; Figure ) was the demographic parameter with the greatest effect on λ in both E. edulis populations. This finding is in accordance with previous studies on long‐lived plant species such as palms (Franco & Silvertown, ; Kouassi, Barot, Gignoux, & Bi, ; Portela, Bruna, & Santos, ; Sampaio & Scariot, ). Similarly, the lower elasticity of sapling growth and fecundity explain why the negative contributions of these demographic processes did not significantly decrease the population growth rate at the altitudinal range limit.…”

Effects of stochastic herbivory events on population maintenance of an understorey palm species (Geonoma schottiana) in riparian tropical forest

“…The higher elasticity of λ to the stasis of reproductive individuals than the vital rates of the initial stages (mainly seed and seedling) found in G. schottiana is similar to the majority of long-lived plant species (Kwit et al 2004, Silvertown et al 1993, Zuidema & Boot 2002 and to the majority of palm species living in different environmental conditions and having different growth forms (Barot et al 2000, Enright & Watson 1992, Kouassi et al 2008, Olmsted & Alvarez-Buylla 1995, Pinard 1993, Souza & Martins 2006. This pattern contrasts with that of herbaceous species, for which seed survival and reproductive fecundity are the main factors responsible for population maintenance (Adams et al 2005, Menges & Quintana-Ascencio 2004, Silvertown et al 1993, Sletvold & Rydgren 2007.…”

Effects of salinity and clonal integration on growth and sexual reproduction of the invasive grass Spartina alterniflora

“…On the other hand, sometimes such a trade-off is not obvious (Liu et al, 2009;Thompson and Eckert, 2004). Generally, the relationship between growth and sexual reproduction is highly plastic in response to different environments (Hautier et al, 2009;Kouassi et al, 2008;Weppler and Stöcklin, 2005). However, little is known about whether there is a trade-off between growth and sexual reproduction as being affected by different salinities.…”