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A comparison of the tropical montane pteridophyte floras of Mount Kinabalu, Borneo, and Parque Nacional Carrasco, Bolivia

Authors


Micheal Kessler Albrecht-von-Haller-Institut für Pflanzenwissenschaften, Abteilung Systematische Botanik, Untere Karspüle 2, 37073 Göttingen, Germany.

Abstract

Aim

To compare the species richness, and taxonomic and life-form composition of tropical montane pteridophyte floras on two well-documented sites: Mount (Mt) Kinabalu, Sabah, Borneo and Parque Nacional (PN) Carrasco, central Bolivia.

Methods

Using published lists, we compared the elevational distribution of overall species richness, specific pteridophyte families, and of life-forms along both study sites. Additionally, we compared point-diversity by establishing 108 plots of 400 m2 at PN Carrasco, and 15 such plots at Mt Kinabalu and three at a lowland site at Danum Valley in south-eastern Sabah, Borneo (200 m).

Results

The numbers of species, genera, and families recorded on Mt Kinabalu were 14–23% higher than at PN Carrasco, most probably as a result of more intensive long-term collecting activity. Opposed to this, species richness per 400 m2 plot was somewhat higher at PN Carrasco, especially amongst epiphytes at mid-elevations. Overall, there was a remarkable similarity in the elevational distribution of species numbers, of individual pteridophyte families, and of life-forms. Major differences included a more pronounced peak of species richness at 1500 m on Mt Kinabalu, considerably higher species numbers of Elaphoglossum at PN Carrasco and of Grammitidaceae at Mt Kinabalu, and a higher proportion of debris-trapping epiphytes and lithophytic species at Mt Kinabalu and of terrestrial herbs at PN Carrasco.

Main conclusions

The majority of present-day species of the studied pteridophyte floras evolved largely independently from about 66–100 common ancestors. The striking convergence of the pteridophyte floras of both sites indicates that the taxonomic and morphological composition of the pteridophyte floras is subject to selective pressure, and that specific pteridophyte families are evolutionarily pre-disposed to occupy specific ecological niches.

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