Journal of Vegetation Science 13: 527-534, 2002 © IAVS; Opulus Press Uppsala. Printed in Sweden - Inherently slow growth of epiphytes - 527 Inherently slow growth in two Caribbean epiphytic species: A demographic approach Schmidt, Gerold1 & Zotz, Gerhard1,2* 1*Lehrstuhl für Botanik II der Universität Würzburg, D-97082 Würzburg, Germany; 2Smithsonian Tropical Research Institute, Apdo 2072 Balboa, Panama; *Correspondencing author; Present address Universität Basel, Schönbeinstrasse 6, CH-4 056 Basel, Switzerland; Fax +41612673504; E-mail
[email protected] Abstract. In relation to the drought-prone and nutrient-poor Epiphyte habitats are mostly referred to as drought- habitat, vascular epiphytes are routinely referred to as inher- prone and nutrient-poor (e.g. Benzing 2000). Epiphyte ently slow-growing plants, although actual evidence is rare. growth and development is thus generally considered to To test this notion we measured in situ growth of the understorey be very slow (e.g. Lüttge 1989; Benzing 1990, 2000), Aspasia principissa Vriesea orchid and the tank bromeliad although only a few studies provide a quantitative basis for sanguinolenta, and, for the latter species, also the growth under favourable conditions in the greenhouse. Using growth this conclusion. For example, in a study on the population analysis we show: (1) that in an intraspecific comparison, structure of Tillandsia circinnata, Benzing (1981) esti- small to intermediate individuals yield the highest relative mated that this bromeliad requires 8-10 yr to reach repro- growth rates (RGR) in situ: A. principissa: 1.6 10-3 d-1; V. ductive size, and Larson (1992) predicts first flowering of sanguinolenta: 3.3 10-3 d-1; (2) that the bromeliad reaches the orchid Encyclia tampensis at an age of ca.