Appendix A. Methods for the review and meta-analysis of avian functional diversity.
Due to space constraints for our review of the functional diversity of birds in tropical agro-ecosystems, we focused on representative studies covering all the major tropical regions of the world (Central America, South America, Africa, Southeast Asia, New Guinea). Since it would be impossible to cover all the studies, especially in the Neotropics, we gave examples of studies with rigorous methodologies which compared avian functional groups in agroecosystems versus undisturbed forest. All studies took place in landscapes that were formerly covered with tropical primary forest, but now consist of a mosaic of forest remnants, agricultural areas, including agroforests, and secondary growth. Below is a list of the references we considered for this review.
Since this review only provides a qualitative outlook on avian functional diversity in agro-ecosystems, we also analyzed a database with standardized entries on the ecology of all the world’s bird species (Sekercioglu et al. 2004), a sample of which can be seen online in that publication as "Supporting Data Set 1".
Although our data sources were mostly authoritative reference books (e.g., del Hoyo et al. 1992–2007, Urban et al. 1986–1999), whose species accounts distilled primary publications, our findings must be interpreted in light of the general nature of our habitat classifications (e.g., our “agriculture” category included pastures, row crops, and plantations along with agroforests) and do not eliminate the need for more detailed analyses focused on purely agroforest birds. Nevertheless, the category “agriculture-forest birds” is a good proxy for agroforest birds since agriculture-forest birds are species that have both agricultural areas and forests among their most preferred habitats. It would be rare for such a species to avoid agroforest systems. We compared various ecological characteristics of forest, agriculture-forest and agricultural bird species using χ2 analysis.
References examined for the bird review
Beehler, B. M., K. S. R. Krishna Raju, and S. Ali. 1987. Avian use of man-disturbed habitats in. the eastern Ghats, India. Ibis 129:197–211.
Carlo, T. A., J. A. Collazo, and M. J. Groom. 2003. Avian fruit preferences across a Puerto Rican forested landscape: pattern consistency and implications for seed removal. Oecologia 134:119–131.
Cockle, K. L., M. L. Leonard, and A. A. Bodrati. 2005. Presence and abundance of birds in an Atlantic forest reserve and adjacent plantation of shade-grown yerba mate, in Paraguay. Biodiversity and Conservation 14:3265–3288.
del Hoyo, J., A. Elliott, and J. Sargatal. 1992–2007. Handbook of the Birds of the World. Lynx Edicions. Barcelona, Spain.
Faria, D., R. R. Laps, J. Baumgarten, and M. Cetra. 2006. Bat and bird assemblages from forests and shade cacao plantations in two contrasting landscapes in the Atlantic Forest of southern Bahia, Brazil. Biodiversity and Conservation 15:587–612.
Greenberg, R., P. Bichier, and A. C. Angon. 2000a. The conservation value for birds of cacao plantations with diverse planted shade in Tabasco, Mexico. Animal Conservation 3:105–112.
Greenberg, R., P. Bichier, A. C. Angon, C. MacVean, R. Perez, and E. Cano. 2000b. The impact of avian insectivory on arthropods and leaf damage in some Guatemalan coffee plantations. Ecology 81:1750–1755.
Greenberg, R., P. Bichier, and J. Sterling. 1997. Bird populations in rustic and planted shade coffee plantations of eastern Chiapas, Mexico. Biotropica 29:501–514.
Johnson, M. D., and T. W. Sherry. 2001. Effects of food availability on the distribution of migratory warblers among habitats in Jamaica. Journal of Animal Ecology 70:546–560.
Komar, O. 2006. Ecology and conservation of birds in coffee plantations: a critical review. Bird Conservation International 16:1–23.
Marsden, S. J., C. T. Symes, and A. L. Mack. 2006. The response of a New Guinean avifauna to conversion of forest to small-scale agriculture. Ibis 148:629–640.
Naidoo, R. 2004. Species richness and community composition of songbirds in a tropical forest-agricultural landscape. Animal Conservation 7:93–105.
Peh, K. S. H., J. de Jong, N. S. Sodhi, S. L. H. Lim, and C. A. M. Yap. 2005. Lowland rainforest avifauna and human disturbance: persistence of primary forest birds in selectively logged forests and mixed-rural habitats of southern Peninsular Malaysia. Biological Conservation 123:489–505.
Peh, K. S. H., N. S. Sodhi, J. de Jong, C. H. Sekercioglu, C. A. M. Yap, and S. L. H. Lim. 2006. Conservation value of degraded habitats for forest birds in southern Peninsular Malaysia. Diversity and Distributions 12:572–581
Perfecto, I., J. H. Vandermeer, G. L. Bautista, G. I. Nunez, R. Greenberg, P. Bichier, and S. Langridge. 2004. Greater predation in shaded coffee farms: the role of resident Neotropical birds. Ecology 85:2677–2681.
Petit, L. J., D. R. Petit, D. G. Christian, and H. D. W. Powell. 1999. Bird communities of natural and modified habitats in Panama. Ecography 22:292–304.
Round, P. D., G. A. Gale, and W. Y. Brockelman. 2006. A comparison of bird communities in mixed fruit orchards and natural forest at Khao Luang, southern Thailand. Biodiversity and Conservation 15:2873–2891.
Sekercioglu, C. H., G. C. Daily, and P. R. Ehrlich. 2004. Ecosystem consequences of bird declines. Proceedings of the National Academy of Sciences (USA) 101:18042–18047. [http://www.pnas.org/cgi/content/full/0408049101/DC1]
Thiollay, J.-M. 1995. The role of traditional agroforests in the conservation of rain and forest bird diversity in Sumatra. Conservation Biology 9:335–353.
Urban, E.K., Fry, H.C., Keith, S. 1986–2000. Birds of Africa. Academic Press. London, UK.
Verea, C., and A. Solozano. 2005. Avifauna associated with a cacao plantation understory in northern Venezuela. Ornitologia Neotropical 16:1–14.
Waltert, M., K. S. Bobo, N. M. Sainge, H. Fermon, and M. Muhlenberg. 2005. From forest to farmland: Habitat effects on afrotropical forest bird diversity. Ecological Applications 15:1351–1366.
Wang, Z. J., and S. S. Young. 2003. Differences in bird diversity between two swidden agricultural sites in mountainous terrain, Xishuangbanna, Yunnan, China. Biological Conservation 110:231–243.