Research on coffee growing

Research on coffee growing

Research: Shade coffee promotes genetic diversity of native trees

Shade coffee farms promote genetic diversity of native trees. 2008. Jha, S. and C. W. Dick. Current Biology 18:R1126-1128.

Chestnut-sided Warbler in winter plumage.

This study looked at genetic differences and gene flow in an understory shrub, Miconia affinis, in a 1200  ha matrix of forest and shade coffee farms in Nueva Alemania, Chiapas, Mexico. Birds are extremely important as agents of seed dispersal in tropical ecosystems. The authors wanted to explore how shade coffee farms — with their attendant suite of vertebrate seed dispersers such as birds, bats, and mammals — might act as corridors or reservoirs promoting healthy gene flow in trees. Other studies have indicated that limited seed dispersal in fragmented landscapes results in inbreeding and demographic declines in tree populations.

Clay-colored Thrush.

Genetic analyses showed that the Miconia in the coffee farms were genetically diverse, and came from multiple source populations. Clusters of Miconia in the forest were actually more closely related to each other than the clusters on coffee farms. The authors speculated that this may be due to the short foraging ranges of birds that specialize in forest habitats, versus the birds found in shade coffee, which are often wide-ranging generalists. [Note that the interpretation of this aspect in the Science Daily article is somewhat misleading. The paper stated that Miconia seeds are spread by birds such as the resident Clay-colored Robin (Turdus grayi) and the migrant Chestnut-sided Warbler (Dendroica pensylvanica), a North American breeder than winters in the tropics. The SD article said that the warbler is a short-ranging forest specialist responsible for limited seed dispersal in forests; this was not stated in the paper.]

The authors conclude that “[S]hade coffee farms support extensive dispersal processes crucial for the connectivity of remnant forest and agricultural habitats…[and they play a role] as potential foci of native forest regeneration.”

Chestnut-sided Warbler by Jerry Oldenettel. Clay-colored Robin by Arthur Chapman.

S. Jha, C. Dick. (2008). Shade coffee farms promote genetic diversity of native trees. Current Biology, 18 (24) DOI: 10.1016/j.cub.2008.11.017

Research on coffee growing

Research: Shade coffee provides additional income besides the coffee crop

Agricultural intensification within agroforestry: the case of coffee and wood products. 2008. Rice, R. A. Agriculture, Ecosystems, and Environment 128:212-218. doi:10.1016/j.agee.2008.06.007

Robert Rice, of the Smithsonian Migratory Bird Center, surveyed 338 owners of coffee farmers in Peru and Guatemala to determine what portion of total income from shaded coffee farms was attributable to non-coffee products derived from the farm. These were smallholders (under 3 ha of coffee; average total farm area was 10 ha in Peru and 6.2 ha in Guatemala). The value of the non-coffee products was based on local market prices, and included the value of products both used/consumed by the farmers, and exchanged or sold.

A fifth to a third of the total value came from non-coffee products. Fruit and fuelwood were the two biggest non-coffee income producers in both countries; lumber for construction materials was also important. Because yields and prices are higher for coffee in Guatemala, the percentage of income derived from non-coffee products was lower there, just under 19%. In Peru, it was 28%.

This is one of the first studies to quantify the “shadow economy” in shade coffee agrosystems that exists alongside of the economics of the coffee production itself. Diversification is particularly important for farmers producing a crop such as coffee, which is so sensitive to global price flucuations. Hopefully, we are also working toward proper appraisal of the value of carbon sequestration and biodiversity preservation in shade coffee systems. When mechanisms are in place to compensate farmers for these less-tangible assets, it should provide further motivation for farmers to foster diverse shade in their coffee holdings.

Forest photo by Alexander Gonzelez.

Research on coffee growing

Research: Meta-analysis of biodiversity loss in coffee farms

Biodiversity loss in Latin American coffee landscapes: review of the evidence on ants, birds, and trees. 2008. Philpott, S. M. et al. Conservation Biology 22:1093-1105. doi:10.1111/j.1523-1739.2008.01029.x

At a recent ornithological conference I attended, I saw a presentation on this paper by one of the authors, my friend Tom Diestch. The authors examined multiple studies of biodiversity impacts of shade coffee management in Latin America (excluding the Caribbean). They wanted to see if there were any patterns to biodiversity loss in these systems. Their results were not surprising. For all taxa (trees, ants, and birds), there was a loss in the number of species as shade management went from rustic to highly-managed shade monoculture or sun coffee.

Compared to forests, there are losses of ant and bird species in most coffee systems, with the exception of rustic shade coffee farms, which had equal or greater ant and bird species richness (number of species) than nearby forests. Most sensitive to habitat changes of the three taxa were ants.

Resident birds, and species specialized in foraging in the canopy or understory, were more impacted by increased management (e.g., less shade) than were migratory species or those that are able to forage in multiple strata. Thus, the diversity of tree species and vegetation characteristics associated with less intense shade management — higher tree density, more vegetation layers, height of canopy and understory — were very important to birds.

The authors made several recommendations:

  • Since species are lost whenever forest is managed, remaining forest patches should be preserved.
  • Rustic coffee should be encouraged — but not to the point where forest is being cut down or substantially disturbed to grow coffee.
  • Sun coffee and similar intensively managed farms should be restored to multi-story canopies with more diverse shade to provide more habitat, and native trees should be included in the restoration.

Many farmers believe that shade coffee results in a lowering of coffee yield. Studies have indicated however that optimum yields come in at around 40-60% shade, and that shade actually helps farmers due to decreased pests (if predators are present) and increased pollination services.

The authors speculate that low production in rustic shade might actually be due to a lack of attention to the crop, and measures can be taken to increase yield without removing vegetation. If there is lowered yield and farmers do take an economic hit, then consumers or other funding mechanisms (e.g., a “payment for ecosystems services” program) should pay a premium to farmers who grow coffee under rustic conditions.

You get what you pay for. I know I’m willing to pay a little more to preserve biodiversity.

Research on coffee growing

Research: Higher beetle diversity in shade coffee, more pests in sun

Simplification of a coffee foliage-dwelling beetle community under low-shade management. C. E. Gordon, B. McGillb, G.Ibarra-NÁºÁ±ezc, R. Greenberg, and I. Perfecto. 2008. Basic and Applied Ecology, in press. doi:10.1016/j.baae.2008.04.004

This study looked at beetle abundance and diversity in coffee farms with high shade or low shade in the Soconusco region of the state of Chiapas in southern Mexico. Farms with low shade systems had lower or equal number of individual beetles, but fewer and more similar species than high shade systems. One beetle species, the dreaded coffee berry borer, la broca (Hypothenemus hampei), however, was far more abundant in the low shade farms (201 total on the low shade farms versus 23 on the high shade farms).

Another example of how shade may help reduce costs to the farmer, in this case, pest control.

Research on coffee growing

Research: Shade coffee = more pollinators = higher fruit set

Pollinator diversity increases fruit production in Mexican coffee plantations: The importance of rustic management systems. C. H. Vergara and E. I. Badano. 2009. Agriculture, Ecosystems & Environment 129: 117-123.

Although arabica coffee is self-pollinating, it can benefit from the activity of insect pollinators. This study looked at pollinators in coffee farms in Veracruz, Mexico that used various types of shade management. Rustic shade had the highest number of pollinating species (12), closely followed by polyculture shade (11). Sun and specialized shade (shade monoculture) had the least number of species (5 and 4).  The more shaded farms also had significantly higher fruit set, which was positively related to the diversity of pollinators.

This has important economic implications. Coffee farmers need to see the economic advantages to any change in their management practices. It is often believed that shade results in lower yields. In this case, we see that increased shade (especially diversity in the shade management) encourages a wider diversity of pollinating insects, which in turn leads to higher fruit set in the coffee and thus higher yields.

Photo of bee pollinating coffee by Ganesh Subramaniam.

Research on coffee growing

Research: migratory birds provide pest control, increase profit, in Jamaican coffee farms

Ecological and economic services provided by birds on Jamaican Blue Mountain coffee farms. 2008. Kellermann, J. L., M. D. Johnson, A. M. Stercho, and S. C. Hackett. Conservation Biology 22:1177-1185.

There have been several good papers published lately on coffee farming that I will be summarizing, but this was the most interesting to me, as I have seen the data presented at recent ornithological conferences.

This study looked at the benefits birds provide by preying on coffee berry borers at four coffee farms in Jamaica’s Blue Mountain region: Clifton Mount, Wallenford, McGraham, and Rowan’s Royale. Rowan’s Royale is the only certified organic coffee farm in Jamaica. All others used the pesticide endosulfan four months before this study began. To see if birds were eating coffee berry borers, the authors excluded birds from some coffee plants to look at the rate birds were preying upon coffee berry borers.

Coffee trees in which birds had no access had higher rates of borer infestation and greater damage. Unprotected trees had rates of infestation that were up to 14% lower, and the declines were determined to be due to birds preying on the borers.

Seventeen bird species preyed on coffee borer beetles; eleven were North American migrants wintering in Jamaica. The decline of the borer infestations on coffee trees accessible to birds coincided with the arrival of migrant birds to the island. Three migrant species did most of the work: Black-throated Blue Warbler, American Redstart, and Prairie Warbler (right).

The authors calculated that the value of pest control provided by birds (via increased yield) to farmers averaged US$75 per ha of coffee, not a small sum considering there are 10,000 ha of coffee in Jamaica and the per capita gross income in the country is US$3400. This figure did not include any additional economic benefits such as reduction of other pests, the potential for savings in pesticide reduction, or additional environmental benefits of not using highly toxic endosulfan.

One important component to this study was the finding that these bird species increased with close proximity to native forest patches, and declined steeply on coffee plots that were further than 40 to 50 meters from a habitat patch. In order for farmers to receive these ecological services and economic benefits from the birds, they need to provide habitat for them! Preserving native forest is a win-win situation for the farmers and the birds.

Black-throated Blue Warbler photo by yours truly; American Redstart by my talented friend Steve Hamilton; Prairie Warbler by Scott A. Young.

J. L. Kellerman, M. D. Johnson, A. M. Stercho, S. C. Hackett. (2008). Ecological and economic services provided by birds on Jamaican Blue Mountain coffee farms. Conservation Biology, 22 (5), 1177-1185 DOI: 10.1111/j.1523-1739.2008.00968.x

Research on coffee growing

Research: Sumatran coffee weak on preserving forest biodiversity

Philpott, S. M., P. Bichier, R. A. Rice, and R. Greenberg. 2008. Biodiversity conservation, yield, and alternate products in coffee agrosystems in Sumatra, Indonesia. Biodiversity Conservation 17:1805-1820.

The vast majority of field research on biodiversity conservation in coffee agrosystems has taken place in Latin America. For that reason, there has been some criticism that using “shade coffee” for conservation may not apply to coffee growing regions in other parts of the world. So this paper, by well-known coffee researchers currently or formerly associated with the Smithsonian Migratory Bird Research Center, is a welcome addition to the literature.

This study took place in and around Bukit Barisan Selatan National Park in Lampung province, southwestern Sumatra. Last year, the World Wildlife Fund reported that 30% of the park has been lost to illegal agriculture, mainly coffee which was documented as having been purchased by Kraft and other large roasters (this post summarizes the report’s findings; more on the status of these farms later in this post).

This study looked at differences in vegetation, ants, birds, and crop characteristics between forest in the park, and coffee plots both within and outside the park. These farms all cultivate robusta, not arabica, coffee. Robusta is typically grown in full sun, but it has been shown to benefit (via higher yields) from some shade, especially in poor soil conditions.

Not surprisingly, and consistent with other studies, coffee plots, whether inside or outside the park, had fewer species of trees, ants, and birds than the forest. The forest had far more canopy cover, denser canopy thickness, taller trees, and more epiphytes than any of the coffee plots.

The Oriental White-Eye (Zosterops palpeborsus) was one of the most commonly encountered species in forest, but it was not found in coffee plots either within or outside the park.

Various metrics between coffee plots within or outside the park were actually quite similar, including amount of canopy cover (around 32%), and number of species of trees, ants, and birds. However, although the number of species was similar, there was very little similarity in the species composition of all taxa between coffee plots and forests. This is in contrast with studies looking at the same variables in Chiapas, Mexico, which found much higher similarity between forests and coffee plots. It indicates that these robusta coffee farms in Sumatra do not maintain most forest species.

There are some contributing factors that make coffee farms in this area poor reserves for biodiversity. Sumatran coffee farms use very few species of shade trees, including the non-native Gliricidia sepium, which may not provide proper resources for native fauna. In general, the farms had very poor soil conservation practices, no use of organic fertilizers or compost, and minimal ground cover. Farmers will need help in sustainable agriculture management to help alleviate these problems.

This will be challenging enough for the legal farms outside the park. As for the ones inside, some of the 15,000 families which have illegal plots in the park have been there for up to 20 years, and there is little place in the surrounding landscape for them to farm if they are removed — even if they are provided incentives for farming outside the protected area. Sadly, other studies have indicated that even if they are removed, forest recovery is slow in this area and expensive restoration efforts would likely be required in order to rehabilitate agricultural encroachments.

It sounds like the bulk of this coffee is sold to the large multinational roasters for grocery store blends, who could well afford to assist in developing sustainable agricultural in the area that supports biodiversity and farm family income. These results also suggest to me that consumers should be looking to buy sustainably-grown arabica coffee from Sumatra, purchased via roasters who have relationships with their farmers.

Photo by Lip Kee under a Creative Commons license.

Research on coffee growing

Blogging bird and coffee research

At the Partners in Flight 4th International Conference

Background
Wearing my occupational hat as an ornithologist, I just attended the Partners in Flight (PIF) conference in south Texas. PIF is a consortium of conservation agencies and organizations that partner to conserve birds — the emphasis is often on migratory landbirds. Because these birds do not recognize human boundaries, cross-border cooperation is a hallmark of PIF.

Coffee in the paper sessions
The first day, I attended a full-day symposia on conservation projects in Central America. Several described the identification of Important Bird Areas (IBAs) in countries such as Nicaragua, El Salvador, and Guatemala. Each speaker identified “sustainable agriculture” and “promotion of high-value cash crops” as a priority means of conserving these key bird conservation sites. Maps of the regions all showed IBAs which included areas whose primary land use was coffee production.

Another researcher looked at whether shade coffee might be a threat to forest birds. She examined whether chickens, always a familiar site wandering around in diverse farms in the tropics, could harbor disease that is passed on to forest birds. The chickens in her study did harbor various signs of diseases (though at a much lower level than “industrial” fowl), and some species of forest birds also showed evidence of exposure to them. However, there was no sign that there was increased mortality or an effect on population, since contact between chickens and forest birds was pretty limited.

The highlight of the meeting for me was an entire morning devoted to a dedicated shade coffee symposia, led by Robert Rice of the Smithsonian Migratory Bird Center. I have written up the abstracts on the papers presented (download as a Word doc), and will incorporate this information in future posts.

Here I’d like to mention a theme that popped up in much of the research and dominated the discussion section: the importance of forest fragments in coffee farms and coffee-growing regions in general.

There was wide agreement that remnants of forest in or adjacent to coffee farms were vital to the preservation of biodiversity. These can be more important than the managed shade on the farm, especially if shade trees are sparse or of only one or a few species.  A researcher from Costa Rica talked about how many farms there planted small plots of sun coffee and used forested strips (planted or natural) as windbreaks. A Colombian researcher said that in some regions there was so much cloud cover that coffee could not be grown under any type of canopy, but the forested patches owned by the farmers harbored many forest birds. Neither of these farm types would qualify for shade certification, but the forest fragments were critical refugia for birds and other fauna.

The question that arose was how could farmers be rewarded for preserving these patches? And what if they did not own adjacent forest, such as protected areas owned by the government? So many tropical parks are “protected” only on paper, and local people do not see the benefit in a hands-off approach. Could there be away to provide incentive for stewardship of these forests as well, by incorporating that into shade certification criteria as well?

Other certification challenges were discussed as well, but I will leave some for future posts.

As I have written about before, Cerulean Warblers are a declining migratory species often associated with shade coffee, and they have been the subject of several papers. Both the American Bird Conservancy and their Colombian partner ProAves have booths in the exhibit hall. I have written about their efforts to preserve Cerulean Warbler habitat, including shade coffee farms, and their Cerulean Warbler Conservation Coffee. This coffee has been sold out for quite awhile, but they now have a new crop which has just been roasted by Thanksgiving Coffee Company, the roaster partner in this worthy endeavor.

And, yes — this conference only served sustainable coffee. Caffe Ibis is the exclusive provider, and all participants were told to bring their own mugs! Randy Wirth, co-owner and roaster of Caffe Ibis, gave a talk about his work in sustainable coffee, from visiting many of his sources (often multiple times), and his tireless work with both consumers and the coffee industry to promote and inform about sustainable coffee. We have many similar ideas about this issue, and I hope to have an opportunity to interview him for C&C some time in the future.

Look for other news and thoughts coming out of the PIF conference in future posts!

Birds and other biodiversity / Research on coffee growing

Research: Spiders on Indian coffee farms

Kapoor, V. (2008). Effects of rainforest fragmentation and shade-coffee plantations on spider communities in the Western Ghats, India. Journal of Insect Conservation, 12(1), 53-68.

Ants and butterflies are often the two most studied arthropods on coffee farms, so it was nice to see a paper looking at spiders. The study took place in Tamil Nadu and Kerala states in areas of mid-elevation tropical wet evergreen rainforest that had tea, coffee, and cardamom plantation surrounded by the Indira Gandhi Wildlife Sanctuary. The authors examined the community structure of spiders in two organic shade coffee farms and ten rainforest fragments of various sizes that were also under varying degrees of degradation.

Most of the study discussed the impact (or lack thereof) of fragment size on spider communities. Results regarding the shade coffee farms were limited. First, both of the coffee farms had similar spider density. The species composition in the two farms were more similar to each other than to other fragment types, but one farm did have higher species richness than the other. The author began by noting that the farm with higher richness had more native shade trees, versus the monoculture of non-native Eucalyptus in the other farm. That would be notable, except that the author went on to say that the first farm adjoined two forest fragments, while the other had poor connectivity. This is likely to have a strong effect on spiders with their relatively limited dispersal ability. Another factor mentioned by the author was that the coffee trees in the first (richer) farm were “much taller” than in the other farm. However, the sampling took place in the herbaceous and shrub layer up to 1.6 m, which is not very tall for a coffee tree, so it is unclear to me how this variable may have influenced the results.

One spider species was noted as being commonly found in undisturbed sites but absent from the coffee farms, while three types of spiders were more common in disturbed sites and the coffee farms. Unfortunately, “disturbance” was not specifically defined. Finally, the author admitted there is virtually no information on the natural history of spiders in the Western Ghats, and said this lack of data hindered using them as indicators of habitat disturbance.

Spiders do have many life-history features that should make them good habitat barometers. Despite some shortcomings, this study was a first step in examining spider communities in forested agrosystems. The results also at least suggested that shade coffee farms in this region are utilized more like “disturbed” than pristine sites by spiders, and that these spider communities may show responses similar to those documented for other organisms to forest connectivity and shade management of coffee farms.

Photo of Nephila pilipes, one of the spiders found in this study, by amateur_photo_bore; thanks for publishing under a Creative Commons license.

V. Kapoor. (2007). Effects of rainforest fragmentation and shade-coffee plantations on spider communities in the Western Ghats, India Journal of Insect Conservation, 12 (1), 53-68 DOI: 10.1007/s10841-006-9062-5

Birds and other biodiversity / Research on coffee growing

Research: Butterflies in Indian coffee farms

Adult butterfly communities in coffee plantations around a protected area in the Western Ghats, India. J. Dolia, M. S. Devy, N. A. Aravind, and A. Kumar. 2008. Animal Conservation 11:26-34.

Butterfly diversity was examined in 12 coffee plantations in India’s Western Ghats, a region of high biodiversity. Distance from a protected area, the Bhadra Wildlife Sanctuary, was the most influencial variable for the abundance and richness of butterfly fauna. The closer the coffee farms to the sanctuary, the higher the species richness and abundance. The composition of butterfly species on coffee farms also became less similar to that of native forest as distance from the sanctuary increased.

The proportion of Australian Grevillea robusta, often called silver oak, a fast-growing, sparse shade timber species now being planted in place of native species on Indian coffee farms, did not seem to effect butterfly abundance or diversity (more on silver oak on coffee farms here). However, the authors stated that three or four species of shade trees dominated at the coffee farms, and none seemed attractive to butterflies.  Coffee has traditionally been grown under native, rustic shade, but there has been an increasing use of fewer, often exotic, species and less shade in recent years.

There were some limitations to this study. It took place during the dry season, when there were not many trees and plants in flower in the sanctuary, but some (mostly non-native species) in the coffee farms. Nectar-feeding butterflies of larger species, which are strong fliers, may have therefore been disproportionally represented at farms farther from the sanctuary. The authors also noted a lack of information on host plants for butterfly larvae, but that many feed on understory shrubs and plants, which tend to be absent from coffee farms. Pesticide use also has a detrimental effect on butterflies. Although coffee farms may serve as corridors or provide roosting or basking sites, they may not have adequate resources for reproducing butterflies.

Photo of Blue Tiger (Tirumala limniace), a common south India species, by Challiyan.

J. Dolia, M. S. Devy, N. A. Aravind, A. Kumar. (2008). Adult butterfly communities in coffee plantations around a protected area in the Western Ghats, India Animal Conservation, 11 (1), 26-34 DOI: 10.1111/j.1469-1795.2007.00143.x

Research on coffee growing

Research: Tree species diversity in Veracruz coffee farms

Tree species diversity and vegetation structure in shade coffee farms in Veracruz, Mexico. A. M. LÁ³pez-GÁ³meza, G. Williams-Linera, and R. H. Manson. 2008. Agriculture, Ecosystems and Environment 124:160-172. 10.1016/j.agee.2007.09.008

Fifteen shade coffee farms, under different types of shade management, and two forest reserves in the Coatepec-Huatusco region of Veracruz were compared. Some of the results were as expected, e.g., there were fewer tree species in shade monocultures and the most tree species in diverse polycultures; some of these diverse polyculture farms actually had more species than the two forest reserves sampled.

One of the most interesting revealations in this paper was that the proportion of native tree species was similar across all farms, regardless of management type, at around 79%. Many of these species (71%) were rare, found on only one or two farms. This highlights the importance of coffee farms for preserving native species diversity in this important coffee-growing area, which is becoming highly fragmented and losing forest rapidly. One of the authors found in a previous study that 27 native tree species were no longer found in regional forests, but still existed on shaded coffee farms.

The authors noted that high tree species richness and functional diversity is linked to the fates of many other plant and animal taxa, and that further multi-taxa studies are needed to better evaluate the role of coffee farms in biodiversity preservation. They also suggested that it is imperative for shade coffee agrosystems be explicitly included in regional conservation strategies.

Birds and other biodiversity / Research on coffee growing

Research: Mammals in coffee plantations in India’s Western Ghats

The mammalian communities in coffee plantations around a protected area in the Western Ghats, India. A. Balia, A. Kumarb, and J. Krishnaswamy. 2007. Biological Conservation 139: 93-102.
This study looked at the number of mammal species found in 15 coffee plantations around the Bhadra Wildlife Sanctuary in the Western Ghats of India, and any correlation between the number of species and distance from the park or vegetation characteristics.

First, a bit of background. Climate conditions in India — monsoon seasons followed by long dry periods — require coffee to be grown under a protective canopy of shade trees, usually under a three-tier system. Although coffee plantations have replaced much of the mid-elevation moist deciduous and evergreen forests in India, coffee has at least traditionally used native forest tree species for shade, such as Ficus glomerata (Doomar, Gular, or Cluster Fig), Dalbergia latifolia (Rosewood), Sapindus laurifolius (Soapnut), and Artocarpus integrifolia (Jackfruit tree).

More recently, non-native species have been used in Indian coffee plantations. In the lowest layer, nitrogen fixing species such as Erythrina lithosperma (Dadap; native to the Philippines and Java) and Gliricidia maculata/sepium (native to Mexico and Central America) are planted. The middle layer, trees that shed their leaves in the monsoon and maintain a dense canopy during the summer, are often native Ficus species. For the canopy layer of hardwood, many coffee farmers are now planting a fast-growing, sparse shade timber species from Australia, Grevillea robusta, often called silver oak although not related to North American oak species.

Twenty-eight species of mammals were recorded in the plantations; this included a number of large carnivores (e.g., tigers and leopards) and herbivores (e.g., elephants and deer). Not surprisingly, more species were found in plantations nearer to the sanctuary. The authors concluded that coffee estates act as a buffer around the park for large mammals, protecting them from the direct effects of more intensive agriculture and higher-density human settlements.

The study did not find any negative correlation with Grevillea abundance, but the fact that the estates with the highest proportion of Grevillea were the closest to the sanctuary may have diluted the effect. The percentage of Grevillea was about 30%; a high percentage of this species is usually avoided, because they drop their leaves during the monsoon, a situation which can cause rot.

Nonetheless, the authors noted that the non-native timber species provide few or no resources for resident wildlife and cautioned that “Such conversions not only lead to the loss of biodiversity values of these plantations, but also severely affect the integrity of the adjoining protected areas.”

Certifications / Research on coffee growing

Research: Evaluating benefits of coffee certification programs


Field-testing ecological and economic benefits of coffee certification programs. S. M. Philpot, P. Bichier, R. Rice, and R. Greenberg. 2007. Conservation Biology 21:975-985.

This study looked at the ecological (vegetation, ants and birds) and economic (yield, revenue) aspects of coffee growing for eight cooperatives in Chiapas, Mexico. Farms were certified organic, organic and Fair Trade, or uncertified. None were certified shade-grown, so farms were examined to see if they would meet shade certification criteria.

The authors found no significant differences in vegetation, bird or ant diversity, or percent of forest fauna on farms based on what type of certification they had. While none of the farms had the necessary complexity of vegetation layers that shade certification required, but the other vegetation criteria met by those farms nonetheless corresponded with higher ant and bird diversity. I think this emphasizes the importance of the specific criteria known as “vertical stratification,” or the percent of leaf volume in each of the three layers of vegetation in shaded coffee. I’ll talk a bit more about this in a follow-up post.

Organic farms had a higher number of tree species, and shared more tree, bird, and ant species with forests than uncertified farms or (curiously) those that were certified both organic and Fair Trade.

There was no difference in yield based on certification, contradicting a common perception that without chemical pesticides and fertilizers, yield will decrease.

Farmers with organic or organic and fair trade certification did not always have higher revenues than uncertified farms. Partly this was due to the costs associated with certification programs. Another factor was the differing market prices between the two years of the study. When market prices increased, the premiums for organic coffee rose, but the premium for Fair Trade coffee did not. This can dilute the relative increase for farmers in Fair Trade co-ops, and exposes a previously-discussed weakness in the Fair Trade model. I think the overall lack of substantially higher revenues in certified organic coffee also illustrates the need for some type of a) reform in the cost of certifications and/or b) an increase in the premiums paid to farmers for sustainable coffee — which would require willingness by consumers to pay more.

Research on coffee growing

Research: Ants eat more coffee borers on shade farms

Testing ant predation on the coffee berry borer in shaded and sun coffee plantations in Colombia. I. Armbrecht and M. C. Gallego. Entomologia Experimentalis et Applicata 124:261-267.

The study took place in Apia, Colombia (Risaralda dept.). Prior to the 1990s, this was primarily a shade coffee region, but outside owners came converted farms to sun coffee. Annually about 5% of the crop is lost to the coffee borer or broca, Hypothenemus hampei, an African pest which arrived in Colombia in 1988.

Three shaded and three sun coffee plantations were examined. Canopy cover averaged 79% with 302 shade trees per hectare in shade farms, and 29% and 33 trees per ha in sun farms. A previous study in the same farms found a higher leaf litter ant
diversity in shaded farms than sun farms (32.3 species per square meter
versus 24.3). Although most of the life of the broca is spent inside the coffee cherry, fallen infected cherries are an important source of infestation, so studying the impact of ground ants is relevant. Previous studies in Colombia have also found that ants feed on broca at all their life stages.

More ant species (16) were attracted to broca in shade farms than sun farms (12). More broca adults were removed from traps by ants in shade farms (30.5%) than in sun farms (15.5%).  This provides strong evidence that native ground-dwelling ants are attracted to and feed on broca adults, and that shade management has a positive effect on this biocontrol. The introduction of the broca in Colombia has led to a dramatic increase in pesticide use, which may also be negatively impacting ant biodiversity.

The two shade plantations that had greater than 10 species of shade trees and used no pesticides in this study are la Playita and la Esperanza (not to be confused with the better-known Esperanza estate from Huila, Colombia, H on map). I did not find any sources of coffee from these specific farms, so they may only be contributing to a cooperative.

Birds and other biodiversity / Coffee regions / Research on coffee growing

Research: Forest birds using Costa Rican coffee farms

Persistence of forest birds in the Costa Rican agricultural countryside. C. H. Sekercioglu, S. R. Loarie, F. Oviedo Brenes, P. R. Ehrlich, and G. C. Daly. 2007.  Conservation Biology 21:482-494.

This study radiotracked several species of resident forest birds in the Coto Brus province of southern Costa Rica, now "dominated by sparsely-shaded coffee farms" — recall that in my post on coffee growing in Costa Rica that most farms, including those marketed as "shade" coffee, have few shade trees of only a couple of species, and lack the structural complexity necessary for true biodiversity preservation.  Two of the three species studied, Silver-throated Tanager (Tangara icterocephala) and White-throated Thrush (Turdus assimilis) are more habitat-sensitive and utilized the coffee farms, but were highly dependent on the remaining trees, and spent more time in remnant forest. The third species, Orange-billed Nightingale-Thrush (Catharus aurantiirostris), is more tolerant of deforestation, and preferred coffee farms and second-growth areas. The authors concluded that agricultural areas have high potential conservation value, which can be enhanced with even modest increases in tree cover. Imagine what true shade coffee would do!