Germination rates of old and fresh seeds and their implications on invasiveness of the ornamental Canary Islands date palm (Phoenix canariensis)

In many countries, Canary Islands Date Palms (Phoenix canariensis) have escaped their horticulturally managed settings and have commenced to colonise surrounding natural bushland. While dispersed by various vectors, both birds and canids such as foxes, fluctuating environmental conditions may inhibit germination in the season of deposition. The potential of old, previous season’s seeds to germinate when conditions turn favourable has direct implications on the plant’s ability to establish viable, colonising populations. Nothing is known about the ability of older, previous season’s seeds to successfully germinate. Based in experimental data, this paper shows that that the seeds of Phoenix canariensis exhibit both substantial inter-specimen and inter-seasonal variations in their germination potential. The observed variability is caused by the high genetic diversity inherent in a given palm population, as well as by range of environmental factors. At the present stage it is impossible to separate these two. Directions for further research are outlined.