Abstract

KROMER, Thorsten; GRADSTEIN, S. Robert  and  ACEBEY, Amparo. Diversity and ecology of vascular epiphytes in natural montane forests and fallows of Bolivia. Ecología en Bolivia [online]. 2007, vol.42, n.1, pp.23-33. ISSN 1605-2528.

We studied vascular epiphyte diversity in primary forest and adjacent 15 yr. old fallows in three different sites in the Yungas of Bolivia - in Andean foothill forest in the Parque Nacional Madidi (350 m), in submontane forest near Sapecho (500-1,200 m) and in montane forest in the Parque Nacional Cotapata (1,500-2,200 m). About 530 species of epiphytes (25 families, 113 genera) were recorded. Orchids were the most important family in terms of species number, followed by ferns. A 1.0 ha plot composed of eight subplots with a total surface of 0.32 ha of montane forest had up to 175 species, showing that these forests rank among the richest worldwide in terms of epiphyte diversity. A mid-elevation peak postulated previously for vascular epiphyte diversity was confirmed. Fallows had 60-70% fewer species than neighboring natural forest. The number of species of orchids, bromeliads, Hymenophyllaceae, and Grammitidaceae were much lower in fallows than in primary forest, but hemiepiphytic aroids, Polypodiaceae, and Aspleniaceae were similar. Reduction of epiphytic species diversity in fallows can be explained by structural characteristics and the young age of the fallow trees, the lack of a dense moss cover, and the drier microclimate in the fallows.

Keywords : Andean forests; elevational gradient; secondary vegetation; vascular epiphytes; Bolivia.

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