Demographic trends in Licuala ramsayi (F. Muell.) Domin (Arecaceae), Tam O'Shanter State Forest, Mission Beach, North Queensland

Abstract

Tam O'Shanter State Forest, North Queensland, Australia, includes dense colonies of the Coryphoid palm, Licuala ramsayi (F.Muell.) Domin. A survey of four random plots and one non-random plot in these colonies assessed density at approximately 3125 individuals per hectare, and average height of mature individuals at 10.9 m (with modal peaks in the 8, 11 and 13 m categories). Age distributions, based on height correlations, showed a predominance of mature trees (47.4% - 88.9% over the 5 plots), small numbers of juveniles (12.4% of total sample), and a variable seedling bank totalling 26.1 %. Noticeably low seedling numbers were detected in an area where tourists have access (with a seedling: adult proportion of 6.25%), reinforcing the impression of generally low recruitment indicated by the other plots, at the time of sampling. The inadherence of these age distributions to reverse J-shaped curves may not indicate a declining population but rather dynamic arborescent monocot growth curves, the possible cyclone dependant or altered recruitment of L. ramsayi, and the intricacies of population maintenance within long-lived species.