Unraveling the Relationship Between Habitat and Disease: Do Shade-Grown Coffee Plantations (“Bird-Friendly” Coffee) Pose a Disease Risk for Neotropical Birds in Costa Rica?
Habitat loss and fragmentation has reached unprecedented proportions and is now the leading cause of wildlife species extinction.1 The increased “edge effect” and smaller habitat patch area that results from habitat fragmentation poses a variety of threats to biodiversity, including 1) promoting biological impoverishment as small populations disappear, 2) creating favorable conditions for the persistence of invasive exotic species, 3) favoring the abundance of generalists species, and 4) potentially creating points of artificial aggregation or concentration of wildlife. Disease is one of the most understudied factors affecting wildlife populations. Shade-grown coffee is heavily promoted in the Neotropics as a sustainable agricultural alternative that maintains a diverse and abundant avifauna.2 However, we hypothesized that the shade-grown coffee plantations in Costa Rica, because they are biologically impoverished, promote the persistence of exotic species, favor generalist species in high abundance and are small areas that artificially concentrate wild birds, might serve as disease risks for neotropical birds. We measured various parameters to estimate health, pathogen prevalence and diversity across three replicates of two habitat types (shade coffee vs. nearby forest patches). From 2005–2007, we captured 1,550 birds. Our results thus far indicate that parasite diversity is highest in birds living in shade-grown coffee and wild birds inhabiting these plantations have a higher prevalence of one directly-transmitted disease. Whereby this is unlikely to cause visible mortality, fitness trade-off from investment in immunity is likely to have ripple effects on reproductive output, which can have more subtle, yet important population effects.
The authors would like to thank all of the student field assistants that have participated in this project, in particular Logan Weygandt, as well as local field assistant, Adan Fuentes, the community of San Luis, the support of Drs. Carlos Jimenez and Pedro Villega and many others. This research was funded through a National Science Foundation Graduate Research Fellowship and further supported by the University of Georgia San Luis Research Station.
1. Hilton-Taylor, C. 2000. IUCN Red List of Threatened Species. International Union for the Conservation of Nature, Gland, Switzerland.
2. Perfecto, I., I. Armbrecht, S.M. Philpott, T. Dietsch, and L. Soto-Pinto. 2007. Shaded coffee and the stability of rainforest margins in Latin America. In: Tscharntke, T., C. Leuschner, M. Zeller, E. Guhudja, and A. Bidin, (eds.) The Stability of Tropical Rainforest Margins: Linking Ecological, Economic, and Social Constraints of Land Use and Conservation. Springer, Environmental Science Series, Heidelberg, Germany. Pp. 227–264.