Schmidt. & Zotz 2002 (Article) Vriesea

Inherently slow growth in two Caribbean epiphytic species: A demographic approach

Author(s):—G. Schmidt & G. Zotz

Publication:—Journal of Vegetation Science 13: 527-534. (2002)

Abstract:—In relation to the drought-prone and nutrient-poorhabitat, vascular epiphytes are routinely referred to as inher-ently slow-growing plants, although actual evidence is rare.To test this notion we measured in situ growth of the understorey orchid Aspasia principissa and the tank bromeliad Vrieseasanguinolenta , and, for the latter species, also the growthunder favourable conditions in the greenhouse. Using growthanalysis we show: (1) that in an intraspecific comparison,small to intermediate individuals yield the highest relativegrowth rates (RGR) in situ : A. principissa : 1.6 10 - 3 d - 1 ; V.sanguinolenta : 3.3 10 - 3 d - 1 ; (2) that the bromeliad reachesmaximum size after ca. 15 yr, while the orchid needs at least20 yr; and (3) small V. sanguinolenta plants exhibit a highlyplastic growth response to favourable conditions in the green-house, reaching an almost 10-fold increase in RGR. In spite of a substantial increase in growth under more favourable condi-tions, our results are consistent with the notion that epiphytesare inherently slow growing organisms.

Keywords:—Aspasia ; Epiphyte; Plant size; Panama; RGR; Vriesea