Abstract
The Cameroon volcanic line montane forests host specific avian assemblages with many endemic species. Such unique bird assemblages deserve adequate description for proper protection. For this purpose, we sampled birds in the upper montane forests of Mts Cameroon and Oku situated at ~2,250 m. We combined point counts and continuous observations to describe species composition and estimate densities of particular species. In total, we recorded 106 species; 45 only on Mt Oku, 21 only on Mt Cameroon, and 40 common to both mountains. The higher species richness on Mt Oku was due to non-forest species that invade the forest interior due to recent human disturbance. Endemic species of the Cameroon volcanic line and montane non-endemic species had higher abundances than widespread species in general. As a result, we did not find a positive abundance–range-size relationship for both locations. Our findings support a previously made observation that montane species of the Cameroon volcanic line have higher densities compared to widespread species. However, we also show that the structures of avian assemblages vary between sites as species spatial turnover was lower on Mt Cameroon than on Mt Oku and species common to both were more abundant on Mt Cameroon. This could be attributed to the more pristine forest on Mt Cameroon, with higher annual rainfall but also due to lower human impact and the existence of a continuous forest. Conservation action within the broader landscape context is thus necessary to secure diverse montane forests in West-Central Africa in the future.
Similar content being viewed by others
References
BirdLife International (2012). http://www.birdlife.org/datazone. Accessed 01 Oct 2012
Brooks T, Thompson HS (2001) Current bird conservation issues in Africa. Auk 118:575–582
Brosset A (1981) La periodicité de la reproduction chez le Bulbul de foret equatoriale africaine Andropadus latirostis. Ses indeces demographiques [Reproductive periodicity of A. latirostris, an African equatorial forest Bulbul. Its demographique indices]. Revue d’Ecologie (Terre Vie) 35:109–129
Brown JH (1984) On the relationship between abundance and distribution of species. Am Nat 124:255–279
Connor EF, McCoy ED (2001) Species–area relationships. Encycl Biodivers 5:397–411
Davies RG, Orme CDL, Storch D, Olson VA, Thomas GH, Ross SG, Ding T, Rasmussen PC, Bennett PM, Owens IPF, Blackburn TM, Gaston KJ (2007) Topography, energy and the global distribution of bird species richness. Proc R Soc Lond B 274:1189–1197
De-Iongh HH, Van Weerd M (2006) The use of avian guilds for the monitoring of tropical forest disturbance by logging. Tropenbos Document 17. Wageningen, The Netherlands
Delancey MW, Delancey MD (2000) Historical dictionary of the Republic of Cameroon, 3rd edn. The Scarecrow Press, Lanham
Dowsett-Lemaire F, Dowsett RJ (2000) Further biological surveys of Manenguba and Central Bakossi in March 2000, and an evaluation of the conservation importance of Manenguba, Bakossi, Kupe and Nlonako Mts, with special reference to birds. Unpublished report for WWF-Cameroon
Ekobo A (2003) Survey of large mammals in the Mount Cameroon forest. Final report for WWF Coastal Forests Programme
Fiona GM, Cheek M, Wild C (2000) Rare plants on Mount Oku summit, Cameroon. Oryx 34:136–140
Fishpool LDC, Evans MI (2001) Important bird areas in Africa and associated islands: priority sites for conservation. BirdLife Conservation series no 11. Pisces Publications and BirdLife International, Newbury and Cambridge, UK
Fjeldså J (1999) The impact of human forest disturbance on the endemic avifauna of the Udzungwa Mountains, Tanzania. Bird Conserv Int 9:47–62
Fjeldså J, Rabøl J (1995) Variation in avian communities between isolated units of the Eastern Arc montane forests, Tanzania. Le Gerfaut 85:3–18
Fjeldså J, Kiure J, Doggart N, Hansen LA, Perkin AW (2010) Distribution of highland forest birds across a potential dispersal barrier in the Eastern Arc Mountains of Tanzania. Steenstrupia 32:1–43
Fjeldså J, Bowie RCK, Rahbek C (2012) The role of mountain ranges in the diversification of birds. Annu Rev Ecol Evol Syst 43:249–265
Forboseh PF, Keming EC, Toh CL, Wultof INB (2003) Monitoring of Kilum-Ijim forest bird communities: initial findings. Bird Conserv Int 13:255–271
Fotso RC (2001) A contribution to the ornithology of Mount Oku forest, Cameroon. Malimbus 23:1–12
Fry CH, Keith S (eds) (2004) The birds of Africa. Christopher Helm, London
Gaston KJ, Blackburn TM (2000) Pattern and process in macroecology. Blackwell, Oxford
Graham CH, Smith TB, Languy M (2005) Current and historical factors influencing patterns of species richness and turnover of birds in the Gulf of Guinea highlands. J Biogeogr 32:1371–1384
Gregory RD, Gaston KJ (2000) Explanations of commonness and rarity in British breeding birds: separating resource use and resource availability. Oikos 88:515–526
Grimshaw JM (2001) What do we really know about the Afromontane archipelago? Syst Geogr Pl 71:949–957
Hořák D, Sedláček O, Reif J, Riegert J, Pešata M (2010) When savannah encroaches on the forest: thresholds in bird–habitat associations in the Bamenda Highlands, Cameroon. Afr J Ecol 48:822–827
Huff MH, Bettinger KA, Ferguson HL, Brown MJ, Altman B (2000) A habitat-based point-count protocol for terrestrial birds, emphasizing Washington and Oregon. USDA Gen. Tech Rep PNW-GTR-501
Jankowski JE, Ciecka AL, Meyer NY, Rabenold KN (2009) Beta diversity along environmental gradients: implications of habitat specialization in tropical montane landscapes. J Anim Ecol 78:315–327
Karr JR (1976) Seasonality, resource availability and community diversity of neotropical birds. Am Nat 110:973–994
Keast A (1985) Tropical rainforest avifaunas: an introductory conspectus. ICBP Tech Publ 4:3–31
MacArthur RH, Wilson EO (1967) The Theory of Island Biogeography. Princeton University Press, Princeton
Malcolm JR, Liu C, Neilson RP, Hansen L, Hannah L (2006) Global warming and extinctions of endemic species from biodiversity hotspots. Conserv Biol 20:538–548
Mcknight MW, White PS, Mcdonald RI, Lamoreux JF, Sechrest W, Ridgely RS, Stuart SN (2007) Putting beta-diversity on the map: broad-scale congruence and coincidence in the extremes. PLoS Biol 5:272–281
Njabo KY (2006) Phylogeography and systematics of montane forest birds in Cameroon. Dissertation, Boston University, USA
Orme CDL, Davies RG, Burgess M, Eigenbrod F, Pickup N, Olson VA, Webster AJ, Ding T, Rasmussen PC, Ridgely RS, Stattersfield AJ, Bennett PM, Blackburn TM, Gaston KJ, Owens PF (2005) Global hotspots of species richness are not congruent with endemism or threat. Nature 436:1016–1019
Owiunji I, Nkuutu D, Kujirakwinja D, Liengola I, Plumptre AJ, Nsanzurwimo A, Fawcett K, Gray M, Mcneilage A (2005) The biodiversity of the Virunga volcanoes. Unpublished report, Wildlife Conservation Society, New York
Payton RW (1993) Ecology, altitudinal zonation and conservation of tropical rainforest of Mt. Unpublished report to FAO, Cameroon
R Development Core Team (2012) R: a language and environment for statistical computing. R foundation for Statistical Computing, Vienna. http://www.r-project.org/
Rahbek C, Graves GR (2000) Detection of macro-ecological patterns in South American hummingbirds is affected by spatial scale. Proc R Soc Lond B 267:2259–2265
Raman STR (2003) Assessment of census techniques for interspecific comparisons of tropical rainforest bird densities: a field evaluation in the Western Ghats, India. Ibis 145:9–21
Reif J, Hořák D, Sedláček O, Riegert J, Pešata M, Záboj H, Janeček S, Storch D (2006) Unusual abundance–range size relationship in an Afromontane bird community: the effect of geographical isolation? J Biogeogr 33:1959–1968
Romdal TS, Rahbek C (2009) Elevational zonation of afrotropical forest bird communities along a homogeneous forest gradient. J Biogeogr 36:327–336
Ryan PG, Bento C, Cohen C, Graham J, Parker V, Spottiswoode C (1999) The avifauna and conservation status of the Namuli Massif, northern Mozambique. Bird Conserv Int 9:315–331
Scatena FN, Bruijnzeel LA, Bubb P, Das S (2010) Setting the stage. In: Scatena FN, Hamilton LS, Bruijnzeel LA (eds) Tropical montane cloud forests: science for conservation and management. Cambridge University Press, Cambridge
Sekercioglu CH, Riley A (2005) A brief survey of the birds in Kumbira Forest, Gabela, Angola. Ostrich 76:111–117
Serle W (1981) The breeding seasons of birds in the lowland forest and in montane forest of West Cameroon. Ibis 123:62–74
Sinclair I, Ryan P (2003) Birds of Africa south of the Sahara. Princeton University Press, Princeton
Smith TB, Holder K, Girman D, O’keefe K, Larison B, Chan Y (2000) Comparative avian phylogeography of Cameroon and Equatorial Guinea mountains: implications for conservation. Mol Ecol 9:1505–1516
Sodhi NS, Ehrlich PR (2010) Conservation biology for all. Oxford University Press, Oxford
Stiles FG (1983) Birds in Costa Rican natural history. University of Chicago Press, Chicago
Storch D, Davies RG, Zajíček S, Orme CDL, Olson V, Thomas GH, Ding TS, Rasmussen PC, Ridgely RS, Bennett PM, Blackburn TM, Owens IPF, Gaston KJ (2006) Energy, range dynamics and global species richness patterns: reconciling mid-domain effects and environmental determinants of avian diversity. Ecol Lett 9:1308–1320
Storch D, Keil P, Jetz W (2012) Universal species–area and endemics–area relationships at continental scales. Nature 488:78–81
Taylor PJ, Stoffberg S, Monadjem A, Schoeman MC, Bayliss J et al (2012) Four new bat species (Rhinolophus hildebrandtii Complex) Reflect Plio-Pleistocene Divergence of Dwarfs and Giants across an Afromontane Archipelago. PLoS One 7(9):e41744
Thomas DW (1986) Vegetation in the montane forests of Cameroon. Stuart SN. Conservation of Cameroon montane forests. International Council for Bird Preservation, Cambridge, UK, pp 20–27
Tye H (1986) The climate of the highlands of Western Cameroon. Stuart SN Conservation of Cameroon montane forests. International Council for Bird Preservation, Cambridge, pp 18–19
Wethered R, Lawes MJ (2003) Matrix effects on bird assemblages in fragmented Afromontane forests in South Africa. Biol Conserv 114:327–340
Wethered R, Lawes MJ (2005) Nestedness of bird assemblages in fragmented Afromontane forest: the effect of plantation forestry in the matrix. Biol Conserv 123:125–137
White F (1981) The history of the Afromontane archipelago and the scientific need for its conservation. Afr J Ecol 19:33–34
Williams SE, Williams YM, VanDerWal J, Shoo LP, Johnson CN (2009) Ecological specialization and population size in a biodiversity hotspot: how rare species avoid extinction. Proc Natl Acad Sci USA 106:19737–19741
Acknowledgments
We wish to thank the communities of Bokwango, Bakingili and Oku villages for their support during field work by providing us with field guides and porters to go up the mountains. We are grateful to Francis, Nathaniel and Collins in particular for their kind reception in the Bokwango village. We thank the Department of Environmental Sciences of the University of Buea, Cameroon and in particular Eric Fokam, Philip Tem Dia and Bertilla Sirri for their assistance during the field work. We also thank Kevin Njabo and the IRTC of the UCLA in Yaoundé for their technical support. Ernest Vunan, David Storch and Martin Mikeš helped us with data collection. Arnošt L. Šizling provided kind assistance with SAR calculation. This study was performed with the authorisation number: 2309/PRBS/MINFOF/SG/DFAP/SDVEF/SC of the Ministry of Forestry and Wildlife of the Republic of Cameroon and with the support of Mt Cameroon NP authorities. The research was funded by the Czech Science Foundation (project no. P505/11/1617).
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by Alexander NG Kirschel.
Electronic supplementary material
Below is the link to the electronic supplementary material.
Rights and permissions
About this article
Cite this article
Nana, E.D., Sedláček, O., Bayly, N. et al. Comparison of avian assemblage structures in two upper montane forests of the Cameroon volcanic line: lessons for bird conservation. Biodivers Conserv 23, 1469–1484 (2014). https://doi.org/10.1007/s10531-014-0677-7
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10531-014-0677-7