Abstract
Avian rarity was investigated in ten high-altitude cloud forests in the Andes of Ecuador. Data on species compositions and abundances were obtained by a fully standardized method (standardization for area, altitude, habitat, effort and seasonality). The rare species were isolated from rank-abundance plots on the basis of the quartile definition of rarity. A positive correlation between mean abundances of species and number of sites occupied suggests that high-altitude bird species classified rare by abundance generally can also be classified rare by range. However, it is necessary to be cautious using this result in ranking conservation priorities since the generality is not obeyed by all species. Within the two abundance classes (contains one and two individuals, respectively) represented among the rare species, the one-individual class had significantly more species than the two-individual class. The quantitative rarity of taxa and ecological groupings produced similar results for all sites, while pairwise similarity of rare species between sites was very low. Together with the difficulty of identifying species that are truly rare by abundance, these results imply that sites selected for conservation preferably should be based upon a qualitative evaluation of lists of species referred to vulnerability categories such as endemic, restricted-range, CITES or IUCN threatened/near-threatened species. However, it is necessary also to incorporate other aspects of biodiversity to cover a full range of biotic diversity.
Similar content being viewed by others
References
Arita, H.T. (1993) Rarity in Neotropical bats: correlations with phylogeny, diet, and body mass. Ecol. Applic. 3, 506–17.
Bibby, C.J., Burgess, N.D. and Hill, D.A. (1992a) Bird Census Techniques. London: Academic Press.
Bibby, C.J., Collar, N.J., Crosby, M.J., Heath, M.F., Imboden, C., Johnson, T.H., Long, A.J., Stattersfield, A.J. and Thirgood, S.J. (1992b) Putting Biodiversity on the Map: Priority Areas for Global Conservation. Cambridge: International Council for Bird Preservation.
Bock, C.E. (1984) Geographical correlates of abundance vs. rarity in some North American winter landbirds. Auk 101, 266–73.
Chantler, P. and Driessens, G. (1995) Swifts. A guide to the Swifts and Treeswifts of the World. Sussex: Pica Press.
Collar, N.J. and Stuart, S.N. (1985) Threatened Birds of Africa and Related Islands. Cambridge: International Council for Bird Preservation, and Gland: International Union for Conservation of Nature and Natural Resources.
Collar, N.J., Gonzaga, L.P., Krabbe, N., Nieto, A.M., Naranjo, L.G., Parker, T.A. and Wege, D.C. (1992) Threatened Birds of the Americas. Cambridge: International Council for Bird Preservation.
Collar, N.J., Crosby, M.J. and Stattersfield, A.J. (1994) Birds to Watch 2: the World List of Threatened Birds. Cambridge: BirdLife International.
Faith, D.P. (1995) Phylogenetic pattern and the quantification of organismal biodiversity. In Biodiversity, Measurement and Estimation (D.L. Hawksworth, ed) pp. 45–58. London: Chapman and Hall.
Fjeldså, J. and Krabbe, N. (1990) The Birds of the High Andes. Copenhagen: Zoological Museum, University of Copenhagen, and Svendborg: Apollo Books.
Fjeldså, J. and Rabøl, J. (1995) Variation in avian communities between isolated units of the Eastern Arc Montane forests, Tanzania. Gerfaut 85, 3–18.
Gaston, K.J. (1994) Rarity. London: Chapman and Hall.
IUCN, The World Conservation Union (1994) IUCN Red List Categories. Gland: IUCN.
Kattan, G.H. (1992) Rarity and vulnerability: the birds of the Cordillera Central of Colombia. Conserv. Biol. 6, 64–70.
Kershaw, M., Mace, G.M. and Williams, P.H. (1995) Threatened status, rarity, and diversity as alternative selection measures for protected areas: a test using Afrotropical antelopes. Conserv. Biol. 9, 324–34.
King, W.B. (1981) Endangered Birds of the World. Washington: Smithsonian Institution Press.
Kunin, W.E. and Gaston, K.J. (1993) The biology of rarity: patterns, causes and consequences. Trends Ecol. Evol. 8, 298–301.
Magurran, A.E. (1996) Ecological Diversity and Its Measurement. London: Chapman and Hall.
Poulsen, B.O. (1994) Mist-netting as a census method for determining species richness and abundances in an Andean cloud forest bird community. Gerfaut 84, 39–49.
Poulsen, B.O. and Krabbe, N. (in press, a) Avifaunal diversity of five high-altitude cloud forests on the Andean western slope of Ecuador: testing a rapid assessment method. J. Biogeogr.
Poulsen, B.O. and Krabbe, N. (in press, b) The diversity of cloud forest birds on the eastern and western slopes of the Ecuadorian Andes: a latitudinal and comparative analysis with implications for conservation. Ecography.
Prendergast, J.R., Quinn, R.M., Lawton, J.H., Eversham, B.C. and Gibbons, D.W. (1993) Rare species, the coincidence of diversity hotspots and conservation strategies. Nature 365, 335–7.
Rahbek, C., Bloch, H., Poulsen, M.K. and Rasmussen, J.F. (1993) Avian body weights from southern Ecuador. Bull. Brit. Orn. Cl. 113, 103–8.
Schoener, T.W. (1987) The geographical distribution of rarity. Oecologia 74, 161–73.
Silva, J.M.C. and Constantino, R. (1988) Aves de um trecho de mata no baixo Rio Guamá — uma reanálise: riqueza, raridade, diversidade, similaridade e preferencias ecológicas. Bol. Mus. Para. Emílio Goeldi, sér. Zool. 4, 201–10.
Terborgh, J., Robinson, S.K., Parker, T.A., Munn, C.A. and Pierpont, N. (1990) Structure and organization of an Amazonian forest bird community. Ecol. Monogr. 60, 213–38.
Thomas, C.D. and Mallorie, H.C. (1985) Rarity, species richness and conservation: butterflies of the Atlas mountains in Morocco. Biol. Conserv. 33, 95–117.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
POULSEN, B.O., KRABBE, N. Avian rarity in ten cloud-forest communities in the Andes of Ecuador: implications for conservation. Biodiversity and Conservation 6, 1365–1375 (1997). https://doi.org/10.1023/A:1018337713601
Issue Date:
DOI: https://doi.org/10.1023/A:1018337713601