I analyzed a set of environmental and vegetation variables in order to characterize an intensification gradient for coffee production agroecosystems. I measured 14 habitat variables within 12 Colombian farms classified into four management systems at the Risaralda region of Colombia: Forests, Polygeneric Shaded coffee, Monogeneric Shaded coffee and Sun coffee plantations. The habitat variables were categorized into three vertical levels: arboreal, shrubs and soil. Univariate and multivariate analyses showed that the habitat effect is driven mainly by drastic changes (i.e. elimination) in the arboreal level along the intensification gradient, although variables at other levels showed gradual and sometimes unexpected changes. I then adapted the management index developed by Mas and Dietsch (2003) to the coffee plantations in this study. The quantitatively supported management index showed a close correspondence to the initial qualitatively classification of the farms. I conclude that intensification of coffee production has clear measurable effects on habitat characteristics and that the management index reflects the gradient of intensification in the studied farms. The approach of using the management index could be highly valuable for the programs of shade coffee certification and conservation goals.
Agricultural intensification has been defined as the patterns of land-use change with the common feature of increase resource use to augment agricultural production (Giller et al. 1997). It is generally associated with specialization, increasing mechanization and generalized use of agrochemicals and other external inputs (Giller et al. 1997; Decaens and Jimenez 2002). This intensification negatively impacts the agricultural land, which is usually the matrix among forest fragments and therefore valuable for conservation purposes (Vandermeer and Carvajal 2001, Perfecto and Vandermeer 2002). There is growing awareness in the literature that agroecosystems should be a priority in the biological conservation agenda (Paoletti et al. 1992; Pimentel et al. 1992; Vandermeer and Perfecto 1997; McNeely and Scherr 2003) due to growing evidence that some agroecosystems are repositories of high levels of biodiversity (Pimentel et al. 1992; Roth et al. 1994; Perfecto et al. 1996, 1997; Perfecto and Armbrecht 2003).
It has been well documented that agroecosystems with high planned biodiversity foster high levels of associated biodiversity and that the intensification of agriculture negatively affects associated biodiversity (Andow 1991; Pimentel et al. 1992; Decaens and Jimenez 2002; Perfecto and Armbrecht 2003). Swift et al. (1996) have hypothesized several predictions regarding alternative patterns in which associated biodiversity decreases with intensification of agriculture. However, testing mechanistic hypotheses first requires the quantification of intensification.
The coffee agroecosystem has received considerable attention over the last decade with regard to the effect of intensification on biodiversity (Nestel et al. 1993; Perfecto et al. 1996, 1997; Greenberg et al 1997a; Moguel and Toledo 1999; Dietsch 2003; Armbrecht and Perfecto 2003), but there is a need to quantify habitat chances for this particular case. There are two reasons that justify the need for a better quantification: first, coffee production occurs across a wide gradient of agricultural intensification, involving different levels and varieties of shade trees (Moguel and Toledo 1999; Perfecto et al. 1996, 1997;...
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