The Role of Coffee Agroforestry in the conservation of forest tree diversity and community composition
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
vv2188@columbia.edu
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. 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. La Sepultura Biosphere Reserve
Chiapas, Mexico
Coffee farm (n=31)
Forest site (n=10)
Community
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. 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. Plot level (alpha) diversity
Coffee agroforest
Forest
Farm
* P < 0.05; ** P < 0.01; *** P < 0.001; N. S > 0.05.
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. 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. 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
ConventionalAgroforest
agriculture
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).
Editor's Notes
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.
