Bird Responses to Shade Coffee Production
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Animal Conservation (2004) 7, 169–179 C 2004 The Zoological Society of London. Printed in the United Kingdom DOI:10.1017/S1367943004001258 Bird responses to shade coffee production Cesar´ Tejeda-Cruz and William J. Sutherland Centre for Ecology, Evolution and Conservation, School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK (Received 2 June 2003; accepted 16 October 2003) Abstract It has been documented that certain types of shade coffee plantations have both biodiversity levels similar to natural forest and high concentrations of wintering migratory bird species. These findings have triggered a campaign to promote shade coffee as a means of protecting Neotropical migratory birds. Bird censuses conducted in the El Triunfo Biosphere reserve in southern Mexico have confirmed that shade coffee plantations may have bird diversity levels similar to, or higher than, natural forest. However, coffee and forest differed in species composition. Species with a high sensitivity to disturbance were significantly more diverse and abundant in primary ecosystems. Neotropical migratory birds, granivorous and omnivorous species were more abundant in disturbed habitats. Insectivorous bird species were less abundant only in shaded monoculture. Foraging generalists and species that prefer the upper foraging stratum were more abundant in disturbed habitats, while a decline in low and middle strata foragers was found there. Findings suggests that shade coffee may be beneficial for generalist species (including several migratory species), but poor for forest specialists. Although shade coffee plantations may play an important role in maintaining local biodiversity, and as buffer areas for forest patches, promotion of shade coffee may lead to the transformation of forest into shade coffee, with the consequent loss of forest species. INTRODUCTION Sterling, 1997b; Estrada et al., 1998; Megchun´ Guerrero, 1999; Moguel & Toledo, 1999; Petit et al., 1999; Roberts, Coffee is one of the world’s most traded commodities Cooper & Petit, 2000a), the species composition is and the major source of foreign exchange earnings for generally dominated by generalist and opportunistic many developing countries. It is estimated that over species. There is also evidence that differences in species 125 million people worldwide are dependent on coffee richness and composition between native forest and shade for their livelihoods (International Coffee Council, 2001). coffee patches are a function of ecosystem structural Coffee in northern Latin America covers around 44% complexity (Gallina, Mandujano & Gonzalez-Romero, of the total arable cropland (Rice & Ward, 1996). This ´ 1996; Parrish & Petit, 1996; Greenberg et al., 1997b; region has 3.1 million hectares of coffee production and Calvo & Blake, 1998; Megchun Guerrero, 1999), or a generates 34% of the world’s production (Perfecto & ´ function of distance from forest (Parrish & Petit, 1996; Armbrecht, 2002). Roberts, Cooper & Petit, 2000b). In terms of avifauna, In the Neotropics, coffee is an important conservation studies have reported that shade coffee plantations issue because it is often produced in countries identified may provide suitable habitat for several bird species as megadiverse (Perfecto & Armbrecht, 2002). Shade (Greenberg et al., 1997a,b; Wunderle & Latta, 2000). In coffee has higher biodiversity levels than unshaded sun fact, public and scientific interest in coffee increased after coffee (Nestel, Dickschen & Altieri, 1993; Perfecto & studies revealed that a great number of Neotropical Vandermeer, 1994, 1996; Perfecto & Snelling, 1995; migratory bird species winter in shade coffee plantations Wunderle & Latta, 1996; Greenberg et al., 1997a). (Vaninni, 1994; Greenberg, 1996; Wexler, 2002). How- Although some studies have found similar or higher levels ever, shade coffee has been found to be detrimental for of bird species richness in shade coffee in comparison forest associated species (Greenberg et al., 1997b; Roberts to natural forest (Aguilar-Ortiz, 1982; Estrada, Coates- et al., 2000a; Armbrecht & Perfecto, 2003). Estrada & Meritt, 1993, 1994, 1997; Parrish & Petit, In recent years much traditional shade coffee has 1996; Wunderle & Latta, 1996; Greenberg, Bichier & been converted into sun coffee in Latin America. Sun coffee plants grow without shade and insecticides are All correspondence to: Cesar´ Tejeda-Cruz. Fax: +44(0) 1603 extensively used. The combination of insecticides with 592250; E-mail: [email protected] the elimination of the shade overstory may result in 170 C. TEJEDA-CRUZ &W.J.SUTHERLAND reduced biodiversity (Vaninni, 1994; Gallina et al., 1996; Table 1. Sampling effort and altitudinal range of treatments Wunderle & Latta, 1996; Greenberg et al., 1997a). Given the replacement of shade coffee by sun coffee, there have Habitat No. of Altitude been urgent demands to stop the transformation of shade Habitat code samples (m a.s.l.) coffee into sun coffee, with shade coffee being linked in Cloud forest CF 47 1700–2200 public awareness campaigns to forest conservation and Montane rain forest MR 43 1100–1699 the protection of migratory songbirds (Rice & McLean, Lower montane rain forest LM 41 450–1099 1999). Since 1995, conservation organisations have been Rustic coffee RC 46 500–1200 promoting ‘shade coffee’ over ‘sun coffee’ as a way to stop Shaded monoculture SM 55 1000–1600 this trend (National Audubon Society, 1998; Sherry, 2000; Sun coffee SC 4 950–1050 Conservation International, 2001; Wexler, 2002; Rappole, Total samples 236 King & Vega Rivera, 2003). However, to divide coffee production systems into ‘traditional’ versus ‘modern’ or m a.s.l., metres above sea level. ‘shade’ versus ‘sun’ does not reflect the real complexity of these production systems. In practice, they represent Chiapas, the southernmost Mexican State. It covers almost the extreme ends of a continuum of intensification, with 120 000 ha, comprising a buffer zone of about 93 500 ha several stages between the two extremes. Subsequently, (79%) and five core zones totalling 25 700 ha (21%). The shade coffee conservation value is related to the degree core zones are pristine forest where economic activities of intensification of the system used (Rice & Ward, 1996; are not allowed. The buffer zone is private land, ‘ejidos’ Calvo & Blake, 1998). The usefulness of the campaign (land communally owned) and individual farms. Roughly to promote shade coffee production is debatable since: 14 000 people live in the buffer zone. Approximately (1) biodiversity found in shade coffee is impoverished by 60% of the buffer zone (56 000 ha) is densely forested, the presence of generalistic and opportunistic species and with the remaining 40% (approximately 37 400 ha) under a decrease in forest associated species (Canaday, 1996; agricultural production with coffee as the main cash crop Greenberg et al., 1997b; Petit et al., 1999; Roberts et al., as well as small scale maize and cattle ranching, mainly 2000a; Rappole et al., 2003) and (2) this marketing for local consumption (IHN, 1995; INE, 1999). strategy may inadvertently encourage an increase in shade Coffee production systems in El Triunfo can be coffee area at the expense of natural forest (Rappole et al., classified as: (1) rustic coffee, in which the original 2003). tree layer is maintained and coffee bushes substitute for Like most tropical areas, southern Mexico is currently the original understory plants; (2) traditional polyculture, under increasing land use pressure by local people. Our where some original trees are maintained, but coffee is study area, El Triunfo Biosphere Reserve, in Chiapas, grown alongside many useful introduced plants and trees; has one of the most important cloud forest remnants in (3) shaded monoculture, where planted leguminous trees Mexico. This area is considered to be an Important Bird (mainly species of the genus Inga) are almost exclusively Area (Arizmendi & Marquez,´ 2001) and an Endemic Bird used to provide shade for coffee bushes and (4) unshaded Area (Stattersfield et al., 1998) because of the quality monoculture (sun coffee), where coffee is a monoculture and uniqueness of its bird fauna. Coffee production is planted with no tree shade at all (Moguel & Toledo, the main economic activity. It has been estimated that 1999). more than 80% of the buffer zone inhabitants work in In our study area, rustic coffee was present mainly activities related to coffee production. However, coffee in the form of small production units in ‘ejido’ land. expansion has been identified as the main threat to Shaded monoculture was found mainly in the coffee primary ecosystems (IHN, 1995; Tejeda Cruz et al., 1997). ‘fincas’ (large, single-owned coffee plantations). Finally, Moreover, Conservation International is currently running sun coffee was very localised in small stands in some of the its flagship project, namely ‘Conservation Coffee’, with biggest plantations. The original natural forest from which small coffee growers in El Triunfo’s buffer and influence the coffee plantations were derived can be separated into areas. Hence there is an urgent need to investigate the cloud forest, montane rain forest and lower montane rain effects of different coffee production systems on biota forest (Breedlove, 1981). There is an important altitudinal at a local scale. Our objectives were to analyse how variable that may have an effect on the results. Table 1 different shade coffee systems affect bird community shows the altitudinal ranges for the treatments studied.