Epifitas

Páginas: 27 (6749 palabras) Publicado: 6 de junio de 2012
Plant Ecology 152: 145–156, 2001.
© 2001 Kluwer Academic Publishers. Printed in the Netherlands.

145

Diversity and abundance of vascular epiphytes: a comparison of secondary
vegetation and primary montane rain forest in the Venezuelan Andes
Wilhelm Barthlott, Viviane Schmit-Neuerburg, Jürgen Nieder & Stefan Engwald
Universität Bonn, Botanisches Institut, Abteilung Systematik undBiodiversität Meckenheimer Allee 170, 53115
Bonn, Germany (e-mail: barthlott@uni-bonn.de)
Accepted 8 February 2000

Key words: Biodiversity, Bioindication, Disturbed vegetation, Podocarpaceae-forest

Abstract
Species diversity of vascular epiphyte plant communities was studied in La Carbonera, a montane rain forest
dominated by Podocarpaceae in the Venezuelan Andes. We compared the epiphytecommunities of the primary,
disturbed, and secondary forest areas of La Carbonera in order to augment the scarce knowledge on the effects
of anthropogenic disturbance on these important elements of tropical vegetation. Diversity of vascular epiphytes
(191 species in the whole forest area) was low in the disturbed and secondary areas (81 spp.) compared to adjacent
primary forest (178 spp.). Fourtypes of disturbed forest and secondary vegetation supported different numbers
of epiphyte species, showing a decline with increasing degrees of disturbance (65 spp. along a road transect,
42 spp. on relict trees in disturbed forest, 13 spp. in a tree plantation and 7 spp. in a former clearing, both secondary vegetation units). Epiphytic species composition in primary and disturbed or secondaryforest areas differed
markedly: disturbed habitats harboured fewer fern and orchid species but more bromeliad species than the primary
forest. Probably the families occurring only in primary forest sites of our study may be useful as bioindicators to
determine the degree of disturbance in other habitats of mountain rain forests as well. Epiphyte abundance was also
lower in disturbed habitats: aremnant emergent tree supported only about half as many epiphyte individuals as a
member of the same species of similar size in the primary forest. The decrease in species numbers and abundance
as well as the differences in species composition are mainly due to the less diverse phorophyte structure and less
differentiated microclimate in the disturbed and secondary vegetation compared to theprimary forest.

Introduction
Epiphytes, a characteristic and distinctive component
of tropical rain forests, have attracted scientific attention since A.F.W. Schimper’s (1888) extensive monograph on neotropical epiphytes. Classical studies on
epiphyte distribution enclose those of Went (1940) and
Johansson (1974).
Montane rain forests are especially rich in epiphytes, which contributesignificantly to total biomass
(Nadkarni 1985, 1992), species diversity (Gentry &
Dodson 1987a, b; Ibisch 1996; Ibisch et al. 1996), and
nutrient cycling (Edwards & Grubb 1977; Nadkarni
1985, 1992) in these ecosystems. They also provide
habitat and food for a variety of insects and birds (Benzing 1984, 1990; Lugo & Scatena 1992; Nadkarni

1992). Epiphytes have also been used extensively by
man formedical, agricultural and horticultural purposes (Bennett 1992; Nadkarni 1992; Rauh 1992).
It has been suggested that epiphytes can be used as
bioindicators of climatic changes, pollution, and ecological damage (Richter 1991; Lugo & Scatena 1992;
Engwald 1999). The importance of epiphyte studies
for biodiversity research has been emphasised recently
by Porembski & Barthlott (2000).
Todaytropical rain forests, and montane rain
forests in particular, are subject to logging and land
use with serious consequences for resident epiphytes.
Epiphyte abundance, species numbers and community
composition were shown to be significantly lower in
secondary than in primary forest (Turner et al. 1994).
However, documentation is scanty (e.g. Olmsted &

146

Figure 1. La Carbonera...
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