The Ecological Benefits of Shade-Grown Coffee The Case for Going Bird Friendly®
By Robert Rice, with assistance from Mauricio Bedoya
Published: September 2010
The market for organic, shade-grown coffee grown to the Smithsonian Migratory Bird Center's Bird Friendly® criteria reached more than $3.5 million in 2008, averaging a 145% annual increase between 2000 and 2008. About 1,400 growers in 8 countries and more than 45 roasters in the U.S., Canada, the Netherlands, and Japan carr Bird Friendly® coffee imported by 16 companies.
However, until today, no one report had collected the wide-ranging benefits of shade-grown coffee production. By reviewing more than 50 studies on shade-grown coffee farms in regions ranging from Central and South America to Indonesia over the past 15 years, the Smithsonian Migratory Bird Center (SMBC) can now make the case that shade-grown coffee production is the next best thing to a natural forest, and put to rest any arguments about the sustainability of a sun-coffee system.
In study after study, habitat on shade-grown coffee farms outshone sun-grown coffee farms with increased numbers and species of birds as well as and improved bird habitat, soil protection/erosion control, carbon sequestration, natural pest control and improved pollination. While sun-grown systems can have higher yields, the shaded farms easily outperform them in sustainability measurements with the trees providing an array of ecological services that offer both direct and indirect "income/payback" to farmers and the environment.
The "hidden yield" in the shade vs. sun comparison is that of the non-coffee products and opportunities coming from the shaded system. In addition to ecotourism on several shade coffee farms, firewood, fruits, building materials and medicinal plants are all resources harvested to varying degrees by shade coffee farmers and used and/or sold by farmers.
Excitingly, some of the studies in Mexico and Costa Rica were supported with funds from royalties remitted to SMBC by roasters involved in the BF program.. Over the past decade, SMBC has given more than $100,000 to researchers looking into the benefits of shade coffee production and other questions related to migratory birds.
Over 95 percent of BF coffee comes from coffee farms in Central and South America with the remainder coming from Africa. The producers manage more than 12,000 acres (5,000 hectares) of BF area and coffee farms in Colombia, Ecuador, El Salvador, Ethiopia, Guatemala, Mexico, Peru, and Venezuela, producing more than 6 million pounds of BF coffee in the 2007-2008 harvest year. Peru ranks first in Bird Friendly coffee production (39 percent), and together, Peru, Guatemala and Mexico account for 77 percent of all production.
The Ecological Benefits of Shade Grown Coffee: The Case for Going Bird Friendly
Since the introduction of the shade-grown coffee concept to the industry by the Smithsonian Migratory Bird Center (SMBC) in 1996 at the First Sustainable Coffee Congress it organized and hosted, the concept of shade-grown coffee has garnered attention from importers and roasters looking to capture segmented markets, particularly in the specialty coffee sector. Many coffee producers, of course, have long known the benefits of shade.
Now consumers can be happy to know that the shade-grown coffee they drink has extensive environmental value. And there is evidence that shade improves the taste.
Below is an overview of the ecological benefits of shade-grown coffee production, the result of a review of more than 50 studies on the subject conducted in many producing countries over the past decade. These agroforestry systems—coffee grown in association with a diversity of trees providing shade as well as ecotourism opportunities and useful products such as firewood, fruits, medicinal plants, and construction materials—act, as the name implies, in many ways as forests.
For example, shade coffee trees provide extensive habitat oftentimes in regions wracked by forest destruction and other landscape transformations harmful to natural ecosystems and their functioning. The forest-like conditions of these systems allow for a wealth of ecological dynamics to occur including increased bird habitat, soil protection/erosion control, carbon sequestration, natural pest control, and improved pollination, making such systems vital for conservation initiatives.
While not all shade coffee farms might meet the SMBC's rigorous Bird Friendly® (BF) criteria (developed in 1997 following the Coffee Congress) for what constitutes quality shade in terms of habitat, scientific field work bolsters the notion that having a mix of trees reaching a specific height and foliage density (see the BF criteria at nationalzoo.si.edu/bf) is a positive land management practice that enhances biodiversity.
It is the high species and structural diversity of these shaded systems that creates the forest-like conditions, resulting in agricultural land use with environmental value. Such farms cannot replace natural forest (many animal species require natural areas). However, they support significant numbers of species, create the conditions for ecological processes, and help to maintain landscapes that would otherwise be much poorer in biodiversity.
Strict comparisons between BF certified and non-certified shade farms are few, so the information in this report comes largely from studies done on farms of varying levels of shade, some of which might well qualify as Bird Friendly. Where contrasts can be made with BF farms specifically, we note that. And given that the BF certification is considered by industry experts to be the most rigorous shade certification, any of the benefits of shade presented here will be enhanced where BF farms are found.
Of course, the benefits of shade-grown coffee production only exist for coffee produced beneath a canopy that truly mimics forest conditions. Over the years, some companies have made claims their coffee is shade-grown but have failed to get it certified to any particular criteria, creating what could be dubious or outright false marketing claims. The only way for consumers to know for sure about the shade claims is to look for the seal from a third party independent body that shows the production meets strict standards. The Bird Friendly® logo is such a seal.
With the US market for Bird Friendly coffee witnessing a hundred-fold increase between 2000 and 2008 (with an average 145 percent annual increase) and amounting to at least $3.5 million in 2008, the studies show that the ecological benefits of shade-grown coffee are just as good as the coffee itself.
Below, we address the benefits of shade-grown coffee in terms of habitat, soil conservation, pest control and pollination, and water, carbon storage, and climate change.
Species Diversity and Habitat:
As a general rule, managing more trees as shade cover in coffee provides better habitat and supports a more diverse wildlife community than managing fewer trees. The few head-to-head comparisons between Bird Friendly (BF) and non-Bird Friendly coffee farms that have been conducted reveal that, for maintaining biodiversity, the BF farms provide a better habitat.
- Shade-grown coffee systems in Latin America, Africa and Asia have all been found to harbor high diversity of shade trees
- Taller and more structurally diverse shade tends to have more bird diversity than shorter, more architecturally uniform shade.
- A study in southern Mexico found nearly 60% of forest birds use BF farms, compared to only 40% in non-BF farms.
- Other studies in Mexico show that between 40% and 56% of forest ants were found in BF farms, compared to only 26% to 30% in non-BF farms. Not only is ant diversity an indicator of habitat health, but ants often aid in natural pest control.
- Coffee plantations in southern Mexico (Chiapas) offer habitat for 180 species of birds (46 of them migratory), a richness rivaled only by natural forest habitats in the region.
- BF-quality farms in the Venezuelan Andes were shown to support up to 14 times the density of migratory birds compared to local primary forest (likely due to a greater abundance of bird-dispersed, small-fruit tree and shrub species, as well as more flowering plants that attract insects).
- In a study of shade versus sun coffee comparisons in Guatemala, overall bird abundance and diversity were 30% and 15% greater, respectively, in shaded farms than sun farms.
- As management practices become more intensive (moving away from traditional shade-grown coffee management to monocropping), the diversity of tree, birds and ants all decline.
- Shade-grown coffee areas in a number of countries tend to have a greater variety of tree species than local forest remnants.
- A shaded coffee farm has trees that yield fruits, some of which might be of value to the farmer and animals-and some only useful to animals. Fruit Energy Availability (a measure that combines fruit abundance, fruit size, and fruit caloric value) associated with the shade trees provides a valuable resource for birds and, as one of several variables examined in Costa Rican coffee farms, accounts for more than half (52%) of bird richness (number of bird species) on such.
- Birds wintering on BF-quality farms in Venezuela showed improved body condition (compared to those in forests in the area) during their time there, a critical issue for making the journey north in the spring. This finding is likely a result of the availability of more small-fruited plants useful to birds and plant flowers that attract insects, offering a buffet of resources.
- Trees in shaded coffee systems often harbor epiphytes such as bromeliads and orchids, the presence of which enhances bird diversity—birds like the bush-tanager are five times more likely to emigrate from a shade-grown coffee farm without epiphytes compared to a farm with epiphytes (based on a study in Mexico supported by BF funds). Epiphytes can harbor lots of insects as a food source for birds, as well as provide nesting material for resident birds.
- Up to 65% of cerulean warblers banded one year in Venezuela returned to the same coffee plantations the following year, emphasizing the importance of quality habitat (shade-grown coffee) and site fidelity (repeated use of a habitat in migratory birds).
The presence of a tree cover on what are often very steep mountainous landscapes in high-rainfall areas helps stabilize slopes and minimize soil erosion. The tree roots, leafy canopy cover, and leaf litter on the ground all help do this.
- The mere presence of agroforestry buffers (strips of different tree species) within agricultural fields has been associated with increases in soil carbon, soil nitrogen, and enzyme activity (all of which are important factors for soil fertility and plant health), as well as an increase in the presence of "water stable aggregates" (a soil structure feature that inhibits erosion).
- In an eight year study in Colombia, shade-grown coffee lost 0.24 metric tons of soil per hectare per year, compared to a hay field's 23 metric tons and a corn field's 860 metric tons being lost per hectare per year. Natural forests erosion rates can range between 0.03 and 0.3 metric tons per hectare per year, making shade coffee comparable to these natural systems.
- Sun coffee systems in Venezuela suffer twice the soil loss from erosion compared to shaded systems.
- Trees used in alley cropping (strips alternating with coffee) in Indonesian coffee farms reduced erosion by 64% compared to areas without trees.
- A study in Nicaragua showed that open-sun coffee lost more than 2.5 times the soil lost by a shade-grown coffee on the same hill sides.
- In Nicaragua, carbon content in the soil (an indicator of soil fertility) of shaded coffee was found to be 18% higher than that found in coffee with little or no shade.
- Fertility measurement (expressed at cation exchange capacity) in Nicaraguan shade-grown coffee farms revealed a 19% increase when compared to farms with little or no shade.
- Infiltration rates (important for soil moisture and plant growth) in unshaded coffee systems in Nicaragua decreased by as much as 75% over a time span of 6 to 10 years
- Soil moisture in sun coffee farms can be 42% lower compared to coffee farms that have leafy foliage as canopy.
Pest Control and Pollination:
A widely accepted ecological concept maintains that diversity creates ecological stability. In lay terms, that means a more bio-diverse system such as a shade-grown coffee farm with many species of plants supports more highly diverse fauna. The various animals—including insects and other arthropods, birds, lizards, and more-form complex and dynamic food webs, an important aspect of the overall ecological workings of a healthy environment. Birds display greater predation on insect larvae in more shaded coffee systems. Insects such as bees help to pollinate trees, flowering plants and coffee, and predators keep insect pests that might otherwise harm production in check.
Even though the shade-grown coffee system is a farmer's managed land, the diversity and complexity of the vegetation creates a setting that mimics many of the physical and ecological characteristics of a natural habitat. Of course, it's not nearly so complex or rich as untouched forests, but for an agricultural land use, it can be impressive when we see what such diversity yields.
- Coffee farms in Costa Rica that have flowering plants within their borders have higher bee diversity than those without such flowering resources (nectar and pollen). Bee pollination has been shown to increase yields in coffee.
- Bee species diversity increases fruit set in coffee: in Indonesia, coffee plants visited by 3 species of bees had 60% fruit set; those with 20 species or more had 90% fruit set.
- A study in Guatemala found that birds can reduce herbivorous insect presence on coffee from 64 to 80%--and excluding birds from coffee plants resulted in greater insect damage to coffee leaves.
- Where birds were excluded from coffee plants in a study in Jamaica, researchers saw a 70% increase in the proportion of coffee fruits infested with the Coffee Berry Borer, coffee's most feared insect pest.
- The same study in Jamaica found migratory birds responsible for 73% of the predation incidences (eating) on the Coffee Berry Borer. The primary predators were Black-throated Blue Warblers, American Redstarts and Prairie Warblers-all neotropical migratory birds.
- Keeping birds out of shade-grown coffee areas in Chiapas, Mexico resulted in a 30% and 64% increase in arthropods like caterpillars and other chewing insects (which can damage leaves and reduce photosynthesis or introduce disease) on coffee in the dry and wet season, respectively.
- Biological control by birds acting as predators on the Coffee Berry Borer in Jamaica was calculated to be worth $75/hectare in 2005, averaging $1004 per farm studied. This equals approximately 30% of the per capita gross national income for that time.
- While birds control insects at day, nighttime finds bats to be important arthropod predators in shade-grown coffee. A Chiapas, Mexico study found that arthropod (insects, spiders, mites, etc.) presence in coffee increased by 84% during the wet season when bats were excluded from the coffee plants. Of course, not all arthropods are "bad" in such systems; some are predators themselves on insect pests of coffee.
- In addition, the leaf litter that serves as protective mulch gets incorporated into the soil eventually, adding organic matter that maintains healthy soil structure and recycles nutrients-very similar to a forest situation.
Water, Carbon Storage, and Climate Change:
A study based on 7,000 farmers in Mexico and Central America predicts that global warming trends will shrink coffee area by as much as 30% by 2050. Thus, it is important to take action to mitigate human-based activities resulting in climate change. Some of these changes are predicted to occur in areas of high-quality coffee production, like the Veracruz region of Mexico.
The mere biomass associated with the shade tree component of coffee agroforestry systems can easily be seen as a carbon sink, where carbon is bound up in the trunks, limbs, and leaves (above ground biomass) as well as the roots (below ground biomass). As with natural forests, the carbon sequestered within a shade-grown coffee farm's shade trees will be locked up in the wood (as opposed to being in the atmosphere and adding to global warming) until the trees are removed. Moreover, the soil itself incorporates carbon from the organic matter that accumulates and gets broken down over time. The presence of trees in shade-grown coffee farms, then, can help keep carbon out of the atmosphere, as well as act as a possible buffer to future temperature increases brought on by climatic change. In addition, as with natural forests, the presence of trees can help protect water supplies in both quantity and quality.
- Nitrogen-fixing trees in shade-grown coffee can put up to 100 kilograms of nitrogen per hectare per year into the soil, potentially reducing the amount of fertilizer a farmer would have to apply by 25 to 30%.
- On a per hectare per year basis, leguminous (nitrogen-fixing) trees such as Erythrina spp. can increase the soil nitrogen content by 31% when sun and shade-grown coffee systems are compared (111 kilogram per hectare per year versus 145 kilogram per hectare per year).
- With nitrogen fertilization (a common practice in non-organic coffee production), coffee farms without shade trees leach more nitrate into the ground water supply than shaded farms, contaminating the stored water.
- Shade-grown coffee systems in Indonesia have soil carbon stocks in the upper 30 centimeter soil layer that are equal to 60% of those found in primary forest there, and they show 58% more total carbon stock (soil and biomass) than sun coffee.
- Trees in a coffee agroforestry system greatly influence water cycling via increased rainfall interception, reduced surface runoff, greater retention of water in the soil, and increased infiltration.
- In Sumatra, Indonesia, conversion of sun coffee to shade-grown coffee is credited for the rehabilitation of watershed dynamics, such as improved infiltration (less surface runoff) and recharge of subsurface water resources.
- Long term predictions for carbon sequestration for a shaded coffee system in Costa Rica (commonly not very diverse or dense in terms of shade cover) were calculated at 99 tons of carbon per hectare, compared to only 70 tons per hectare for a pine-oak stand (29% less), 103 tons per hectare for a Norway spruce stand (4% more) and 114 tons per hectare for a Douglas fir-beech stand (14% more). These one and two-species stands, however, are not nearly so diverse as the shade coffee and are managed for eventual and complete removal. Moreover, the general lack of tree diversity and even-age characteristics creates a different (and likely less diverse) habitat overall than does shade coffee.
About Bird Friendly® Coffee
Bird Friendly® Coffee (BFC) carries a seal of approval that assures consumers the coffee has met specific criteria developed by the Smithsonian Migratory Bird Center (SMBC).
Bird Friendly is certified organic coffee produced on farms with a shade cover that provides a substantial and vital habitat for migratory and resident birds in tropical landscapes, which are increasingly threatened by deforestation globally at an unprecedented rate. The Bird Friendly criteria are the world's most stringent standards for shade-grown coffee production. Migratory birds, including the popular Baltimore Oriole, are not only beautiful with vibrant songs, but are integral to tropical and temperate ecosystems alike, providing flower pollination and seed dispersal, among other roles.
Sales of organic, shade-grown coffee grown to the Bird Friendly standards of the National Zoo's Smithsonian Migratory Bird Center rose to nearly $3.5 million in 2008, according to a report by Dr. Robert Rice, a geographer at the SMBC. According to the report, The Global Market for Bird Friendly Coffee: 2008 (the most recent data available), the majority (61 percent) of all Bird Friendly coffee roasted was consumed in the United States, followed by Japan (36 percent) and Canada (3 percent).
More than 95 percent of Bird Friendly coffee comes from coffee farms in Central and South America with the remainder coming from Africa. Some 1,400 producers manage more than 12,000 acres (5,000 hectares) of Bird Friendly area and coffee farms, and they produced more than 6 million pounds of Bird Friendly coffee in the 2007-2008 harvest year. Peru ranks first in Bird Friendly coffee production (39 percent), and together, Peru, Guatemala and Mexico account for 77 percent of all production.
The volume of Bird Friendly coffee sold in the United States between 2000 and 2008 increased more than a hundredfold (averaging a 145 percent annual increase), from fewer than 2,000 pounds to 200,400 pounds. There are 44 roasters in the United States, Canada, the Netherlands, and Japan that carry Bird Friendly coffee imported by 16 companies.
Since 2003/2004, SMBC has given more than $100,000 in grants to scientists and to efforts aimed at educating the public about the concept of BF coffee. The grants have supported projects researching various aspects of coffee's role in biodiversity maintenance, as well as to studies focusing on birds in cacao systems, vineyards in California and agrofuels in the mid-western region of the US. The program, funded by a pennies-on-the-pound royalty fee sent to SMBC by Bird Friendly roasters, will continue to support work that explores the connections between birds and coffee, as well as research on birds in other managed lands. These remittances paid by forward-looking coffee roasters help to fund scientific work that would otherwise not be done.
"Bird Friendly®" Coffee Criteria at a Glance
|Height of canopy||≥12 meters for the canopy of the stratum made by the "backbone" species|
|Foliage cover||≥40%, measured during dry season after pruning|
|Floristic diversity of trees and wood shrubs||≥10 woody species (in addition to the backbone species). At least 10 of these should represent 1% or more of all individuals sampled, and be dispersed throughout the coffee holding.|
|Total floristic diversity||The sum of all woody and herbaceous species counted in the sampling.|
|Structural diversity||The "architecture" or profile of the coffee farm should show evidence of some layers or strata-preferably three: 1. The layer formed by the backbone species and other trees of that size; 2. The stratum of taller, emergent species, comprised of native trees of the natural forest; 3. The stratum beneath the principal canopy (that of the backbone species), made up of shrubs and small trees or plants, like Musa spp.and citrus. The emergent and understory strata each should ideally account for 20% of the total foliage volume present. The remaining 60% of the foliage volume should be that of the principal canopy (backbone species and trees of the same height as the backbone species).|
|Leaf litter||Should be present; no minimum percentage required, but, together with living ground cover, soil needs protecting (as with organic criteria)|
|Weeds/herbs/forbs||Should be present; no minimum percentage required.|
|Living fences||Where appropriate and feasible, should be present.|
|Buffer zones along waterways||Should exist and be composed of native vegetation. Along streams they should measure ≥5 meters wide (one each side); for rivers they should be ≥10 meters wide.|
|Visual characterization—"gestalt"||Should qualify at least for the category "Traditional polyculture" (the more diverse category of the polyculture systems)|
|Organic certification||Must have current organic certification by a USDA-accredited certification agency.|
Bird Friendly® Coffee Roasters
9 Community Avenue
Stoney Creek, ON L8E 2X9
Birds and Beans Inc.
2413 Lake Shore Boulevard West
Toronto, ON M8V 1C5
Prague 5, 155 31
Camel Coffee Co., Ltd.
Ogawa Coffee Co., Ltd.
Nishikyogoku, Ukyo-ku, Kyoto 6150802
Andronicas Coffee Co Ltd
91-93 Great Eastern Street
London, EC2A 3HZ
Plantation House Newark Road
Allegro Coffee Company
12799 Claude Court
Thornton, CO 80241
Barrie House Coffee Co., Inc.
4 Warehouse Lane
Elmsford, NY 10523
Beanery Coffee Roasters
1009 1/2 Williams St.
Valdosta, GA 31601
BeanFruit Coffee Company
P.O. Box 320822
Flowood, MS 39232
Birds & Beans LLC
Suite 506 15 River Street
Boston, MA 02108
Black River Roasters
195 Flynn Ave
Burlington, VT 05401
Bohemia Coffee Roasters
P.O. Box 446
Philomont, VA 20131
Caffe Ibis Coffee Roasting Company
52 Federal Avenue
Logan, UT 84321
Gold Country Roasters
78 Scott Street
Murphys, CA 95247
Golden Valley Farms
208 Carter Drive Suite 13B
West Chester, PA 19382
Java Trading Co. (Distant Lands)
801 Houser Way N
Renton, WA 98057
Jim's Organic Coffee
21 Patterson Brook Road
W. Wareham, MA 02576
Lola Savannah, Ltd.
Houston, TX 77002
1 Java Boulevard
Nunica, MI 49448
Nantucket Coffee Roasters
15 Teasdale Circle
Nantucket, MA 02554
Northwestern Coffee Mills
20146 Soderlund Rd
Mason, WI 54856
S & D Coffee
300 Concord Parkway South
Concord, NC 28027
Sun Coffee Roasters
45D Northwest Drive
Plainville, CT 06062
Bird Friendly® Coffee Importers
Kencaf Importing & Distributing, Inc.
500 Alden Road, Suite 212
Markham, ON l3R 5H5
4 rue de Boissettes
SC Foods Co. Ltd.
Harumi Triton Square Office Tower
1-8-11, Harumi, Chuo-ku, Tokyo 104-8610
18 Station Road
Poole, Dorset BH14 8UB
Alexander House 39 London Rd
Sevenoaks, Kent TN13 1AR
D R Wakefield Ltd
Thompson House 42-44 Dolben St
London, SE1 0UQ
Freeman Trading Ltd.
1 Curtain Road
London, EC2A 3LT
Atlantic Specialty Coffee
24301 Southland Drive Suite 600
Hayward, CA 94545
Atlas Coffee Importers, LLC
1402 NW 85th Street
Seattle, WA 98102
3669 Sherbrooke Rd.
Rockford, IL 61114
Coffee Holding Co., Inc.
4401 First Avenue
Brooklyn, NY 11232
Excelco Trading, LP
17 Battery Place, Suite 1711
New York, NY 10004
19500 State Highway 249, Suite 225
Houston, TX 77070
10109 NW 12th Avenue
Vancouver, WA 98685
Paragon Coffee Trading Co.
1 North Lexington Avenue
White Plains, NY 10601
3306 Powell St.
Emeryville, CA 94608
Royal Coffee NY
661 Hadley Rd
South Plainfield, NJ 07080
80 Cottontail Lane
Somerset, NJ 08873
Zephyr Green Coffee LLC
642 Julia Street
New Orleans, LA 70130
Bird Friendly® Coffee Certifying Agencies
- ECOCERT COLOMBIA
- BCS OKO-GARANTIE
- BIO LATINA S.A.C.
- Control Union Peru
- Control Union Indonesia
- OCIA INTERNATIONAL, INC.
- QAI, INC.
- QUALITY CERTIFICATION SERVICES
Ataroff, M. and M. Monasterio, 1997. Soil erosion under different management of coffee plantations in the Venezuelan Andes. Soil Technology 11:95-108.
Bakermans, M. A. Vitz, A. rodewald, and G. Rengifo, 2009. Migratory songbird use of shade coffee in the Venezuelan Andes with implications for conservation of cerulean warbler. Biological conservation 142:2476-2483.
Cruz-Angon, A. and R. Greenberg, 2005. Are epiphytes important for birds in coffee plantations? An experimental assessment. Journal of Applied Ecology 42: 150-159.
Gligo, N., 1986. Agricultura y Medio Ambiente en America Latina. EDUCA/SIAP, Editorial Universitaria Centroamericana. San Jose, Costa Rica.
Granger, S. 2010. Central America coffee land to shrink as globe warms. Reuters News Service, May 19, 2010.
Greenberg, R. , P. Bichier and J. Sterling, 1997. Bird populations in rustic and planted shade coffee plantations of eastern Chiapas, Mexico. Biotropica 29(4):501-514.
Greenberg, R. P. Bichier, A Crus, C. MacVean, R. Perez and E. Cano, 2000. The impact of avian insectivory on arthropods and leaf damage in some Guatemalan coffee plantations. Ecology 81(6):1750-1755.
Kellerman, J., M. Johnson, A. Stercho and S. Hackett, 2008. Ecological and Economic Services Provided by Birds on Jamaican Blue Mountain Coffee Farms. Conservation Biology, Volume 22, No. 5, 1177?1185
Klein, A., I. Steffan-Dewenter and T. Tscharntke, 2003a. Pollination of Coffea canephora in relation to local and regional agroforestry management. Journal of Applied Ecology 40:837-845.
Klein, A., I. Steffan-Dewenter and T. Tscharntke, 2003b. Fruit set of highland coffee increases with the diversity of pollinating bees. Proceedings of the Royal Society of London 270:955?961.
Laderach, P., M. Lundy, A. Jarvis, J. Ramirez, E. Perez, K. Schepp, 2009. Predicted impact of climate change on coffee supply chains. Paper prepared at International Center for Tropical Agriculture (CIAT) office in Managua, Nicaragua.
Mas AH, Dietsch TV (2004) Linking shade coffee certification to biodiversity conservation: butterflies and birds in Chiapas, Mexico. Ecological Applications 14:642?654
Masera, O. et al, 2003. Modeling carbon sequestration in afforestation, agroforestry and forest management projects: the CO2FIX V.2 approach. Ecological Modeling 164 (2003) 177?199.
Perfecto, I., A. Mas, T. Dietsch, and J. Vandermeer. 2003. Conservation of biodiversity in coffee agroecosystems: a tri-taxa comparison in southern Mexico. Biodiversity and Conservation 12:1239?1252.
Perfecto, I., J. Vandermeer, G. Lopez, G. Ibarra, R. Greenberg, P. Bichier and S. Langridge, 2004. Greater predation in shaded farms: the role of resident neotropical birds. Ecology 85(10): 2677?2681
Perfecto, I. and J. Vandermeer, 2010. The agroecological matris as alternative to the land-sparing/agriculture intensification model. PNAS Early Edition, accessed at www.pnas.org/cgi/doi/10.1073/pnas.0905455107
Perfecto, I., R. Rice, R. Greenberg and M. Van der Voort 1996. Shade coffee: a disappearing refuge for biodiversity. BioScience 46(8):598-608.
Philpott, S., P. Bichier, R. Rice and R. Greenberg, 2007. Field-testing ecological and economic benefits of coffee certification programs. Conservation Biology 21(4):975-985.
Philpott, S., W. Arendt, I. Armbrecht, P. Bichier, T. Dietsch, C. Gordon, R. Greenberg, I. Perfecto, R. Reynoso-Santos, L. Soto-Pinto, C. Tejeda-Cruz, G. Williams-Linera, J. Valenzuela, and J. Zolotoff 2008. Conservation Biology 22(5):1093-1105.
Philpott, S., B. Lin , S. Jha and S. Brines 2008. A multi-scale assessment of hurricane impacts on agricultural landscapes based on land use and topographic features Agriculture, Ecosystems and Environment 128(1-2):12-20.
Rice, R. 1990. Transforming Agriculture: The Case of Coffee Leaf Rust and Coffee Renovation in Southern Nicaragua. Dissertation in Geography, University of Caflifornia, Berkeley. 304 pp.
Rice, R. 2008. Agricultural intensification within agroforestry: The case of coffee and wood products. Agriculture, Ecosystems and the Environment 128:212-218.
Van Noordwijk, M., S. Rahayu, K. Hairiah, Y. Wulan, Farida, B. Verbist, nd. Carbon stock assessment for a forest-to-coffee consersion landscape in Sumber-Jaya (Lampung, Indonesia): from allometric equations to land use change analysis, accessed at www.worldagroforestrycentre.org/SEA/Publications/files/.../PP0157-05.PDF
Vaast, P., Bertrand, B., Perriot, J.-J., Guyot, B. and Genard, M., 2006, Fruit thinning and shade improve bean characteristics and beverage quality of coffee (Coffea arabica L.) under optimal conditions. Journal of the Science of Food and Agriculture, Vol. 86, p. 197.
Vaast, P., J. Beer, C. Harvey, J. Harmand , 2005. Environmental services of coffee agroforestry system in Central America: a promising potential to improve the livelihoods of coffee farmers? communities. Paper presented at the conference 'Integrated Management of Environmental Services in Human-Dominated Tropical Landscapes', CATIE, Turrialba, Costa Rica.
Williams-Guillen, K., I. Perfecto, J. Vandermeer, 2008. Bats limit insects in a neotropical agroforestry system. Science 320:70