Two contrasting strategies have been proposed for conserving biological diversity while meeting the increasing demand for agricultural products: land sparing and land sharing production systems. Land sparing involves increasing yield to reduce the amount of land needed for agriculture, whereas land-sharing agricultural practices incorporate elements of native ecosystems into the production system itself. Although the conservation value of these systems has been extensively debated, empirical studies are lacking. We compared bird communities in shade coffee, a widely practiced land-sharing system in which shade trees are maintained within the coffee plantation, with bird communities in a novel, small-scale, land-sparing coffee-production system (integrated open canopy or IOC coffee) in which farmers obtain higher yields under little or no shade while conserving an area of forest equal to the area under cultivation. Species richness and diversity of forest-dependent birds were higher in the IOC coffee farms than in the shade coffee farms, and community composition was more similar between IOC coffee and primary forest than between shade coffee and primary forest. Our study represents the first empirical comparison of well-defined land sparing and land sharing production systems. Because IOC coffee farms can be established by allowing forest to regenerate on degraded land, widespread adoption of this system could lead to substantial increases in forest cover and carbon sequestration without compromising agricultural yield or threatening the livelihoods of traditional small farmers. However, we studied small farms (<5 ha); thus, our results may not generalize to large-scale land-sharing systems. Furthermore, rather than concluding that land sparing is generally superior to land sharing, we suggest that the optimal approach depends on the crop, local climate, and existing land-use patterns.

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SummaryThe Golden-cheeked Warbler Dendroica chrysoparia is a federally endangered Neotropical migrant that inhabits montane pine-oak forests in Mexico and northern Central America during the non-breeding season. Although it is known that Golden-cheeked Warblers are closely associated with 'encino' oaks (evergreen or holm oak) such as Quercus sapotifolia, Q. eliptica and Q. elongata, which have shiny, narrow, elliptical, or oblong leaves, quantitative habitat targets are useful for effectively incorporating this information into conservation planning and forest management practices. We analysed data on wintering Golden-cheeked Warblers collected during the non-breeding season in Honduras from 1996 to 1998 to identify quantitative targets for habitat conditions for this species. Data on warbler abundance were collected using line transect surveys located in montane pine-oak forests in a stratified-random fashion. Habitat data were collected at five 0.04 ha plots on these same transects and the averaged values used as predictors of Golden-cheeked Warbler abundance. We found that Golden-cheeked Warblers were strongly associated with the basal area of encino oaks and density of 'roble' oaks, such as Q. segoviensis, Q. purulhana and Q. rugosa, which have large, lobed leaves. Density of Golden-cheeked Warblers peaked at 5.6 m 2 ha -1 basal area of encino and 7 roble oaks ha -1. These values can be used to identify quantitative habitat targets that can be directly incorporated into forest management practices to ensure that these activities maintain habitat conditions necessary for their use by Golden-cheeked Warblers. ResumenEl Golden-cheeked Warbler es una especie migratoria Neotropical que habita en bosques montanos de pino y cedro en Méjico y la parte norte de Centro América durante la época de no apareamiento. Es conocido que los Golden-cheeked Warblers están fuertemente asociados con encino cedros tales como el Quercus sapotifolia, Q. elíptica y Q. elongata, identificados por tener hojas muy brillantes, alongadas elípticas o también oblongadas. Para definir parámetros de conservación, es importante obtener objetivos cuantificables para que efectivamente se incorpore este tipo de información en las prácticas de manejo forestal y planeamiento de su conservación. Nosotros analizamos datos en Golden-cheeked Warblers hibernando que fueron colectados durante la estación de no reproducción en Honduras entre 1996 a 1998 para identificar objetivos cuantitativos de las condiciones del ambiente aplicables a esta especie. Datos sobre la abundancia de Warblers fueron colectados utilizando encuestas con líneas transectales localizadas en regiones montanas forestales de pino y encino estratificadas en una forma aleatoria. Datos sobre el ambiente se colectaron en áreas de 0.04 hectáreas en las mismas líneas transectales y los valores promedios se usaron para predecir la abundancia de Golden-cheeked Warblers. Encontramos que los Golden-cheeded Warblers están fuertemente asociados con áreas basales de encino cedro y densidades de r...