The Role of Coffee Agroforestry in the conservation of forest tree diversity and community composition


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This presentation was given by Vivian Valencia at the World Agroforestry Congress in New Delhi. 10-14 February 2014.

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  • In the type of agroforestry systems that I work with, crops such as coffee and cacao are cultivated underneath the canopy of forest trees. There are over 20 years of studies documenting its importance as habitat for insects, amphibians, birds, and small mammals, outside of protected areas, in otherwise highly human-dominated landscapes, where agroforests improve the quality of the agricultural matrix. Many of this studies have looked at diversity over a management gradient, and have found the more rustic systems to have higher biodiversity levels.Other type of studies have compared the diversity in agroforests to that of forests and in many cases have found comparable richness and diversity levels between the two systems.However, one issue with this type of studies is that they rarely look beyond the numbers. and although comparable richness levels may be compared, it may be that we are not conserving the same species. Some researchers have suggested that specialist, rare, and mature-forest species species do not thrive in agroforests.In this research project, we went attempted to go beyond the numbers.
  • Here, we examined whether coffee agroforestry systems can serve as conservation reservoirs of tree species native to nearby forests.
  • According to the ministry of agriculture, Mexico is the number one exporter of organic coffee in the world, and chiapas is the number one state in the production of coffee. La Sepultura is the ideal place to address these questions because it is located in an important coffee growing region that also overlaps with areas of high species diversity and endemism.SBR encompasses an area of 167,309 ha, of which 8% is designated as core area, destined for the protection of biodiversity and educational and research activities, and 92% as buffer zone restricted to human activities compatible with “sound ecological practices” Zoning restrictions prohibit any type of human activity, other than research, in the core areas (inner red polygons). BUT allows shade coffee expansion.167,309 ha
  • Saplings >50cm in height but <5 cm dhbDbh> 5cmdbhCount and id coffee varietyDensiometer in four points approx 9 m form center
  • We compared tree diversity, composition and structure between coffee agroforests and forests in La Sepultura Biosphere Reserve in Chiapas, Mexico.
  • We  used an analysis of similarities (ANOSIM) to statistically test whether there is a significant difference between farms and forest sites. Results from ANOSIM indicated that community composition of forests and farms are more similar within each group than would be expected by random chance (R statistic=0.4281 and p-value=0.01). The stress value for the NMDS was 19; stress values up to 20 indicate a useful and ecologically interpretable picture (Clarke, 1993).
  •  The conservation value of coffee agroforestry also depends on the role it plays vis-à-vis other land uses. We must distinguish between coffee agroforestry as an additional agricultural activity that is expanding into forests, versus coffee agroforestry as a substitute for conventional agriculture. In this case, agroforestry is improving the quality of the landscape by occupying space otherwise devoted to more detrimental forms of agriculture; this land use trajectory is preferable, from an ecological standpoint, since it propels the reforestation of tree-less landscapes and eliminates or at least reduces overgrazing, soil erosion, and/or heavy use of agrochemicals. This substitution scenario grants coffee agroforestry its most promising role in conserving the biodiversity of a landscape. In this scenario, coffee agroforestry presents a viable conservation strategy that does not involve the modification of remaining forests.
  • The Role of Coffee Agroforestry in the conservation of forest tree diversity and community composition

    1. 1. The role of coffee agroforestry in the conservation of tree diversity and community composition of native forests in a Biosphere Reserve Vivian Valencia a*, Luis García-Barrios b, Paige West c, Eleanor Sterling d, ShahidNaeema a Dept. of Ecology, Evolution, and Environ. Biology, Columbia University, New York,USA bEl Colegio de la FronteraSur (ECOSUR), Chiapas, Mexico cDept. of Anthropology, Columbia University, New York, USA dAmerican Museum of Natural History, New York, USA Vivian Valencia PhD Candidate/ Faculty Fellow Columbia University
    2. 2. Background Well-documented conservation value of coffee agroforestry as habitat for many taxa, as buffer zones, and in improving the quality of the agricultural matrix. Forest Coffee agroforest vs. Diversity
    3. 3. Research Question What is the role of coffee agroforestry in conserving tree diversity & community composition found in native forests? Forest VS Coffee agroforest 1. Floristic richness and vegetative structure 2. Tree community composition 3. Composition by traits of succession 4. Presence & abundance of tree species of conservation concern
    4. 4. La Sepultura Biosphere Reserve Chiapas, Mexico Coffee farm (n=31) Forest site (n=10) Community
    5. 5. Data Collected Field work in coffee farms (n=31) and forests (n=10): • • • • • Tree richness & abundance Canopy openness Elevation Basal area Coffee shrub density Circular plots, 907 m2
    6. 6. Data Analysis • Richness, diversity indices, Chao richness estimator, rarefaction curves • Non-metric multidimensional scaling (NMDS) • Classified trees according to – Succession stage – Conservation concern status (critically endangered, endangered, or vulnerable)* Differences between forest &agroforest analyzed with t-test * Based on the IUCN Red List of Threatened Species and The Red List of Mexican Cloud Forest Trees
    7. 7. Plot level (alpha) diversity Coffee agroforest Forest Farm * P < 0.05; ** P < 0.01; *** P < 0.001; N. S > 0.05.
    8. 8. Landscape level (gamma) diversity Coffee agroforest Forest
    9. 9. Results: Landscape level Coffee agroforest Forest Farm Coffee agroforest Forest
    10. 10. Species community composition: NMDS on species abundance data Analysis of similarities (ANOSIM) P-value=0.01
    11. 11. Community composition by succession stage and conservation concern status Inga spp. *** *** *** *** *** *** * P < 0.05; ** P < 0.01; *** P < 0.001; N. S > 0.05.
    12. 12. Why do we see this? • Mixture of ecological and social processes. • Social: – Farmers’ believes of which trees are good for coffee – Legacy of past policies that promoted Inga trees – Knowledge is based on experience, family & friends, NGOs, government. • Not all supported by scientific information • Ecological: – Changes in microclimate, opening of canopy, soil disturbances – Landscape matrix (i.e., proximity to forest vs. crop field)
    13. 13. What does this mean? The conservation value of coffee agroforestry also depends on the role it plays vis-à-vis other land uses. Forest Agroforest ConventionalAgroforest agriculture
    14. 14. Thank you! ¡Gracias! Dhanyawaad Contact: Vivian Valencia
    15. 15. Acknowledgements • We would like to thank the coffee farmers of the participating communities for their contribution to this study. • Taxonomist M. Martínez-Icó (ECOSUR) and C. Morales Diaz (ECOSUR) for field support. • Research was supported by the Earth Institute Travel Grant, Institute of Latin American Studies Pre-Dissertation Field Research Grant, E3B Biology Pre-dissertation Grant, and El Colegio de la Frontera Sur (ECOSUR).