Plant Ecology

, Volume 213, Issue 9, pp 1393–1412

Host tree utilization by epiphytic orchids in different land-use intensities in Kathmandu Valley, Nepal

  • Yagya Prasad Adhikari
  • Hagen Siegfried Fischer
  • Anton Fischer
Article

DOI: 10.1007/s11258-012-0099-0

Cite this article as:
Adhikari, Y.P., Fischer, H.S. & Fischer, A. Plant Ecol (2012) 213: 1393. doi:10.1007/s11258-012-0099-0

Abstract

We studied the influence of site conditions on epiphytic orchids under a subtropical climate in the Kathmandu Valley, Nepal. We analysed 96 systematically distributed grid points situated in Kathmandu Valley across a land-use intensity gradient (national park to urbanised city area). Geographical Information System (GIS) and remote sensing were used for classification of land-use types. We identified 23 species of epiphytic orchids, within 13 genera, from 42 different host tree species. Host preference is obvious for some orchid species (e.g., Dendrobium nobile), with certain tree species (e.g., Schima wallichii, Ficus religiosa) hosting more orchid species than others. The orchid Rhynchostylis retusa was the most common species found on many different host tree species across the land-use intensity gradient. Host species and host bark characteristics (e.g., rugosity, pH and exposure to wind) played a vital role for orchid distribution, with lower abundance in areas of higher impact. Under strong human impact (urban city area), F. religiosa was the dominant host tree, with large individual trees (mean diameter in breast height, dbh = 1.3 m) providing the habitat for considerable populations of R. retusa individuals. In general, epiphytic orchids were found on larger host trees in urban areas than in areas of lower human impact. We found that some hosts are more likely to harbour orchid species, especially native host species. Older larger trees with rougher bark, low pH, exposed to wind and reduced human impact provided better habitats for orchids. We suggest these characteristics should be considered in urban planning to reduce human impact on the associated orchid epiphytic community.

Keywords

Host tree preference Micro-site Gradient Epiphyte Abundance Land-use change Kathmandu 

Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  • Yagya Prasad Adhikari
    • 1
  • Hagen Siegfried Fischer
    • 1
  • Anton Fischer
    • 1
  1. 1.Geobotany, Department of Ecology and Ecosystem ManagementTechnische Universität München, Hans-Carl-von-Carlowitz-Platz 2FreisingGermany

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