Variability in reproductive effort of a keystone species : age and height of branch establishment

Auteur(s) et Affiliation(s)



Description :
Carnegiea gigantea (saguaro, Cactaceae) is a protected and keystone species in the Sonoran Desert upon which nearly all of the ecosystem’s fauna rely. This study assessed the ages and heights of plants when branching commenced under 4 different environmental regimes. Significant variations were observed in the onset of branching across the populations by both age and height, likely related to the interplay between summer precipitation (and thus growth rate) and winter precipitation, which increases branching in any given individual. In all 4 populations, branches developed from areoles that are themselves reproductive (past or present). Further, the delay between the start of fruiting and the production of branches appears to be relatively consistent across populations, around 30 years. Of greatest concern is the advanced age (140 years) at which branching begins at the most arid site, dramatically diminishing reproductive output in an already marginal population.


Type de document :
Article de périodique

Source :
Physical geography, issn : 0272-3646, 2013, vol. 34, n°. 2, p. 136-148, nombre de pages : 13, Références bibliographiques : 30 ref.

Date :
2013

Editeur :
Pays édition : Royaume-Uni, Abingdon, Taylor and Francis