Diversidad y ecología de epífitas vasculares en bosques montanos primarios y secundarios de Bolivia
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Ecología en Bolivia
Abstract
La diversidad de epífitas vasculares en el bosque natural y barbechos adyacentes de hasta 15 años fue estudiada en tres localidades diferentes en los Yungas de Bolivia - en bosque piedemonte en el Parque Nacional Madidi (350 m), en bosque submontano cerca de Sapecho (500-1.200 m) y en bosque montano en el Parque Nacional Cotapata (1.500-2.200 m). Aproximadamente 530 especies de epífitas (25 familias, 113 géneros) fueron registradas. Las orquídeas fueron la familia más importante en lo que se refiere a números de especies, seguida por los helechos. Una parcela de 1.0 ha compuesta de ocho subparcelas con una superficie total de 0.32 ha tenía 175 especies, mostrando que estos bosques montanos forman parte de los más ricos a nivel mundial, en lo que se refiere a la diversidad de epífitas. El pico máximo de diversidad de epífitas vasculares a altitudes intermedias postulada previamente fue confirmado. Los barbechos tenían 60-70% menos especies que el bosque natural adyacente. El número de especies de orquídeas, bromeliáceas, Hymenophyllaceae y Grammitidaceae era mucho más bajo en barbechos que en el bosque primario, pero la riqueza era similar de aráceas hemiepifíticas, Polypodiaceae y Aspleniaceae. La reducción de diversidad de especies de epífitas en barbechos puede explicarse por las características estructurales y la joven edad de los árboles, la falta de una capa de musgos densa y el microclima más seco en este tipo de vegetación.
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.
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.
Description
Vol. 42, No. 1