Factors affecting reproductive behaviour in the New Zealand nikau palm,Rhopalostylis sapidaWendl. et Drude

Abstract

Abstract Inflorescence and seed production was traced over seven consecutive years for the nikau palm, Rhopalostylis sapida, growing in temperate forests of northern New Zealand. Palms reach reproductive maturity when stems exceed a height of about 2.2 m, have about 60 frond scars, and are estimated to be approximately 90 years of age. However, inflorescences on young-mature palms usually aborted, and seed set was low for palms <3 m in height. Both the frequency of fruiting and the size of annual seed crops increased with increasing palm height to a maximum in the 6-8 m height class. However, the pattern of seed production in relation to number of frond scars (a better index of age) suggested declining seed production in old palms. Seed production varied up to three-fold between years and between sites. Seed production palm-1 yr-1 correlated positively with rates of frond fall (= frond production), inflorescences palm-1, and seeds inflorescence-1. Reproductive effort rarely exceeded 50%, possibly because ...