Abstract
The survival chance of epiphytic orchids today not only depends on the natural site conditions required by the orchids but also on anthropogenic changes in site conditions. This study answers two questions: (1) What is the ecological niche of the different epiphytic orchid species? (2) What are the ecological factors that threaten epiphytic orchid’s population under anthropogenic disturbances? Our study area was the Kathmandu valley, Nepal, with its subtropical forest. We established 156 systematically selected sampling points in the Kathmandu area covering different types of ecosystems under human impacts such as densely populated area, agricultural land, mixed agricultural and settled area, old tree patches, and a natural forest in a national park. The ecological niche of the orchid species was analyzed with a principal component analysis (PCA). The correlations between the different site factors were statistically significant. Spearman’s rank correlation matrices showed that the variables land-use intensities with altitude, and height with diameter in breast height (dbh) of host had the highest significant positive correlation coefficient (0.67 and 0.64 respectively). On the other hand, host bark pH and altitude as well as land use had a significantly strong negative correlation coefficient (-0.80 and -0.61, respectively). Different epiphytic orchid species interact differently with the given set of environmental factors: for occurrence of Vanda cristata there is no single environmental factor of special influence, while for Rhynchostylis retusa high bark pH and high light availability are important. First two axis of the PCA explained more than 50% of the total variance. Most orchid species occupy a specific, narrow niche in this ecological space. The main causes of anthropogenic influence of orchid population in the Kathmandu Valley are loss of adequate host trees (species and size) and increasing air pollution, resulting in increasing host bark pH.
Similar content being viewed by others
References
Acharaya KP, Vetaas OR, Birks HJB (2011) Orchid species richness along Himalayan elevational gradients. Journal of Biogeography 38: 1821–1833. DOI: 10.1111/j.1365-2699.2011.02511.x
Ackerman JD, Sabat A, Zimmerman JK (1996) seedling establishment in an epiphytic orchid: an experimental study of seed limitation. Oecologia 106: 192–198.
Adhikari YP, Fischer A (2011) Distribution Pattern of the epiphytic orchid Rhynchostylis retusa under strong human influence in Kathmandu valley, Nepal. Botanica Orientalis–Journal of Plant Science 8: 90–99. DOI: 10.3126/botor.v8i0.5956
Adhikari YP, Fischer A, Fischer HS (2012a) Micro-site conditions of epiphytic orchids in a human impact gradient in Kathmandu valley, Nepal. Journal of Mountain Science 9: 331–342. DOI: 10.1007/s11629-009-2262-1
Adhikari YP, Fischer HS, Fischer A (2012b) Host tree utilization by epiphytic orchids in different land-use intensities in Kathmandu valley, Nepal. Plant Ecology 213: 1393–1412. DOI: 10.1007/s11258-012-0099-0
Adhikari YP (2013) Distribution pattern, micro-site conditions, host tree characteristics and utilization of epiphytic orchids in the central Himalayas. Ph.D. Thesis, Technische Universität München, Germany.
Adhikari YP, Fischer A, Pauleit S (2015) Sustainable conservation perspectives for epiphytic orchids in the central Himalayas, Nepal. Applied Ecology and Environmental Research 13:753–767. DOI: 10.15666/aeer/1303_753767
Barthlott W, Schmit-Neuerburg V, Nieder J, Engwald S (2001) Diversity and abundance of vascular epiphytes: a comparison of secondary vegetation and primary montane rain forest in the Venezuelan Andes. Plant Ecology 152: 145–156. DOI: 10.1023/A:1011483901452
Benzing DH (1990) Vascular epiphytes general biology and related biota. Cambridge University Press, Cambridge, UK.
Callaway RM, Reinhart KO, Moore GW, et al. (2002) Epiphyte host preferences and host traits: mechanisms for speciesspecific interactions. Oecologia 132: 221–230. DOI: 10.1007/s00442-002-0943-3
Chaudhary RP (1998) Biodiversity in Nepal: status and conservation. S. Devi, Saharanpur, India and Tecpress Books, Bangkok, Thailand.
Christenson E (2003) A handbook to the orchids of the Machu Picchu National Sanctuary. The Peruvian Trust Fund for National Parks and Protected Areas (PROFONAPE). Lima, Peru. pp 140.
Demetria MC, Ticktin T (2011) Demographic effects of harvesting epiphytic bromeliads and an alternative approach to collection. Conservation Biology 25: 797–807. DOI: 10.1111/j.1523-1739.2011.01691.x
Farmer AM, Bates JW, Bell JNB (1990) Short communications: A comparison of methods for the measurement of bark pH. Lichenologist 22: 191–197.
Frei JK, Dodson CH (1972) The chemical effect of certain bark substrates on the germination and early growth of epiphytic orchids. Bulletin of the Torrey Botanical Club 99: 301–307. DOI: 10.2307/2997072
Heitz P (2005) Conservation of vascular epiphyte diversity in Mexican coffee plantations. Conservation Biology 19: 391–399. DOI: 10.1111/j.1744-7429.2009.00510.x
Hirata A, Kamijo T, Saito S (2009) Host trait preferences and distribution of vascular epiphytes in a warm-temperate forest. Plant Ecology 201: 247–254. DOI: 10.1007/sl1258-008-9519-6
Hofstede RGM, Wolf JHD, Benzing DH (1993) Epiphytic mass and nutrient status of an Upper Montane Rain Forest. Selbyana 14: 37–45.
Köster N, Nieder J, Barthlott W (2011) Effect of host tree traits on epiphyte diversity in natural and anthropogenic habitats in Ecuador. Biotropica 43: 685–694. DOI: 10.1111/j.1744-7429.2011.00759.x
Krömer T (2003) Diversity and ecology of vascular epiphyte in primary and secondary Bolivians forest. Ph.D. Thesis, Georg-August-University, Gottingen.
Larrea ML, Werner FA (2010) Response of vascular epiphyte diversity to different land-use intensities in a neotropical montane wet forest. Forest Ecology and Management 260: 1950–1955. DOI: 10.1016/j.foreco.2010.08.029
Migenis LE, Ackerman JD (1993) Orchid–phorophyte relationships in a forest watershed in Puerto Rico. Journal of Tropical Ecology 9: 231–240. DOI: 10.1017/S0266467400007227
Mitchell AW, Secoy K, Jackson T (2002) The global canopy handbook. Techniques of access and study in the forest roof. Global Canopy Programme, Oxford, UK.
Mullerova J, Vitkova M, Vitek O (2011) The impacts of road and walking trails upon adjacent vegetation: Effects of road building materials on species composition in a nutrient poor environment. Science of the Total Environment 409:3839–3849. DOI: 10.1016/j.scitotenv.2011.06.056
Nadkarni NM (1984) Epiphyte biomass and nutrient capital of a neotropical elfin forest. Biotropica 16: 249–256.
Nadkarni NM, Parker GG, Rinker HB, Jarzen DM (2004) The Nature of forest canopies, In: Lowman MD and Rinker HB, Forest canopies (2nd eds.). Academic Press. pp 544.
Nieder JP, Michaloud G (2001) Epiphytes and their contribution to canopy diversity. Plant Ecology 153: 51–63. DOI: 10.1023/A:1017517119305
Nkongmeneck BA, Lowman MD, Atwood JT (2002) Epiphytie diversity in primary and fragmented forests of Cameroon, central Africa: A preliminary survey. Selbyana 23: 121–130.
Oksanen, J, Blanchet FG, Kindt R, et al. (2011) Vegan: Community ecology package. R package version 2.12.1. Available online at: http://CRAN.R project.org/package =vegan (Accessed on 12 September 2015)
Otero JT, Flanagan NS (2006) Orchid diversity–beyond deception. Tree 21: 64–65.
Padmawathe R, Qureshi Q, Rawat GS (2004) Effects of selective logging on vascular epiphyte diversity in a moist lowland forest of Eastern Himalaya, India. Biological Conservation 119: 81–92. DOI:10.1016/j.biocon.2003.10.024
Pant PR, Dangol D (2009) Kathmandu Valley profile, briefing paper: governance and infrastructure development challenges in the Kathmandu Valley. Workshop: 11–13 February 2009 Kathmandu Metropolitan City, Nepal. pp 15.
Pimm SL, Raven P (2000) Biodiversity-Extinction by numbers. Nature 403: 843–845.
R Core Team (2013) R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. Available online at: http://www.Rproject. org/(Accessed on 11 September 2015)
Shakya LR., Bajracharya DM, Chettri MK (1994) Conserving the threatened orchids of Kathmandu Valley. Report Series 8. WWF (World Wildlife Fund) Nepal Program, Kathmandu, Nepal.
Shashidhar, KS, Kumar ANA (2009) Effect of climate change on orchids and their conservation strategies. Indian Forester 135: 1039–1049.
Song L, Liu WY, Ma WZ, Tan ZH (2011) Bole epiphytic bryophytes on Lithocarpus xylocarpus (Kurz) Markgr. in the Ailao Mountains, SW China. Ecological Research 26: 351–363. DOI: 10.1007/s11284-010-0790-3
Stuntz S, Ziegler C, Simon U, Zotz G (2002) Diversity and structure of the arthropod fauna within three canopy epiphyte species in Central Panama. Journal of Tropical Ecology 18: 161–176. DOI: 10.1017/S0266467402002110
WCSP (2015) World Checklist of Selected Plant Families. Facilitated by the Royal Botanic Gardens, Kew. Available online at: http://apps.kew.org/wcsp/(Accessed on 9 January 2015)
Werner FA, Homeier J, Gradstein SR (2005) Diversity of vascular epiphytes on isolated remnant trees in the montane forest belt of southern Ecuador. Ecotropica 11: 21–40.
Werner FA, Gradstein SR (2008) Seedling establishment of vascular epiphytes on isolated and enclosed forest trees in an Andean landscape, Ecuador. Biodiversity and Conservation 17: 3195–3207. DOI: 10.1007/s10531-008-9421-5
Wolf JHD, Konings CJF (2001) Toward the sustainable harvesting of epiphytic bromeliads: a pilot study from highlands of Chiapas, Mexico. Biological Conservation 101: 23–31. DOI: 10.1016/S0006-3207(01)00053-2
Wolf JHD (2005) The response of epiphytes to anthropogenic disturbance of pine-oak forests in the highlands of Chiapas, Mexico. Forest Ecology and Management 212: 376–393. DOI: 10.1016/j.foreco.2005.03.027
Zotz G, Thomas V, Hartung W (2001) Ecophysiological consequences of differences in plant size: abscisic acid relationships in the epiphytic orchid Dimerandra emarginata. Oecologia 129: 179–185. DOI: 10.1007/s004420100714
Author information
Authors and Affiliations
Corresponding author
Additional information
http://orcid.org/0000-0003-1963-214X
http://orcid.org/0000-0002-6781-2594
http://orcid.org/0000-0003-1929-5331
Rights and permissions
About this article
Cite this article
Adhikari, Y.P., Fischer, A. & Fischer, H.S. Epiphytic orchids and their ecological niche under anthropogenic influence in central Himalayas, Nepal. J. Mt. Sci. 13, 774–784 (2016). https://doi.org/10.1007/s11629-015-3751-z
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11629-015-3751-z