Birds and other biodiversity

Background information / Birds and other biodiversity

Coffee and biodiversity hotspots

The image above (click to enlarge) is from the May 2002 issue of Scientific American (“Rethinking Green Consumerism” pdf) and shows the overlap of coffee growing areas and biodiversity hotspots (defined as spots housing 44% of all vascular plant species and 35% of all land-dwelling vertebrate animal species). I think this handily illustrates the importance of encouraging — through our purchasing power — coffee farms that preserve habitat, do not use harmful chemicals, and cultivate coffee in a way that is as close as practical to nature.

In 2007, resolve to buy coffee that protects and and cherishes the health of the people who grow it and the environment in which it is grown.  Happy New Year.

Birds and other biodiversity / Research on coffee growing

Research: Biodiversity and profitability in coffee agrosystems

Gordon, C., R. Manson, J. Sundberg, and A. Cruz-Angon.  2006. Biodiversity, profitability, and vegetation structure in a Mexican coffee agrosystem. Agriculture Ecosystems & Environment 118:256-266.

This study looked at coffee grown in various types of shade in central Mexico, and any correlation between biodiversity (in birds and mammals) and profits. The conversion of plantations to sun coffee is generally believed to increase yield (and therefore profits), while the preservation of shade and forest tree species is thought to be costly in terms of decreased yield.  However, the additional costs of chemical inputs and labor in sun coffee may offset any increases in yield.  This study sought to examine this purported trade-off.

They found no support for a trade-off between biodiversity and profitability. Biodiverse, large shade plantations were highly profitable under all price scenarios, even profit calculations did not include any price premiums, such as those received if a farm is certified organic.  The authors concluded that farms and the environment both stand to gain…

“…by dispelling the notion that high-input, low biodiversity and sun and specialized shade coffee cultivation systems are the most economically sensible ways to grow coffee.”

Sites that were shade monoculture (or “specialized shade”) — with a low diversity and density of shade trees — were indistinguishable from sun coffee in terms of abundance and diversity of forest birds.  This emphasizes the point that not all shade coffees preserve biodiversity. These farms have shade trees, could market their coffee as “shade grown,” and may appear to non-biologists as having a lot of birds (which tend to be common, open-area generalists like grassquits and sparrows), but really do not preserve the diversity of species that were present before the native forest was cut down.

Many farmers have the erroneous belief that epiphytes parasitize shade trees, and they remove them. Biodiversity and profitability could immediately increase if farmers stopped this practice (called “destencho”). See this post on the value of epiphytes in coffee farms. Compared to intact forest, even the shaded farms lacked a number of bird and mammal species, in particular those that utilize the understory and ground level.  These are the layers most managed and disturbed in coffee farms.  Diverse shade coffee farms are best at preserving species that live in the upper layers and canopy.

Birds and other biodiversity / Research on coffee growing

Research: Nesting birds in shade coffee

Gleffe, J.D., J. A. Collazo, M. J. Groom, and L. Miranda-Castro.  2006.  Avian reproduction and the conservation value of shaded coffee plantations.  Ornitologia Neotropical 17: 271-282.

Most of the research on birds and coffee farms focuses on migrant birds which breed in North America and winter in the tropics.  This is the first study to examine the nesting success of resident birds in shade coffee plantations compared to secondary forest.  The study took place in north-central Puerto Rico, and the shade coffee farms were in the Ciales area (map).

The majority of bird nests (72%) were found in shade coffee, and 26 species were recorded in coffee, versus 22 in secondary forest. Six species were found only in coffee, two only in forest.

Thirty-two different plant species were used as nest sites in coffee, with the two most common plants used for nesting Inga vera and Andira inermis.  Coffee trees themselves were host to 26% of the nests, many of which were of the Bananaquit (Coereba flaveola), shown here at right. However, it was the canopy trees that were the most important and harbored most of the bird species in both the coffee and forest habitats. The stunning Puerto Rican Woodpecker (Melanerpes portoricensis), an endemic species, is one example of a bird that needs mature canopy trees for nesting. These canopy trees, of course, would not be present in sun coffee plantations, and the authors emphasize that it is the value of shade coffee plantations for preserving birds depends on the shade canopy layer, not the coffee itself.

The study also looked at reproductive success, and discovered that it was similar between coffee and forest, an important finding.  The authors suggest restoration of native shade canopy in existing and new coffee farms to conserve avian diversity in Puerto Rico.  This is especially important because Puerto Rico is experiencing both deforestation due to urban sprawl and development, and the majority of coffee grown there (59%) is sun coffee, with more being converted.  Consumers should choose their Puerto Rican coffee very carefully.  One source I found from the area where the study took place was Finca Cialitos (web site in Spanish, store in English).

Birds and other biodiversity / Research on coffee growing

Research: The value of wild coffee

Hein, L. and F. Gratweiler. 2006.  The economic value of coffee (Coffea arabica) genetic resources. Ecological Economics 60:76-185.

This fascinating paper is not about the sort of ecological research I usually summarize here, but absolutely keeps with the theme of preserving biodiversity, as well as the recent Ethiopian thread that has come up here lately.

First, the authors introduce the importance of ancestral/wild genetic resources in agricultural crops, since careful breeding can impart in existing cultivars genes that can increase yields, confer disease resistance, and improve quality.  Wild coffee, and therefore its genetic resources, are only found where the species originated, in the highland forests of Ethiopia.  The paper highlights two urgent facts:

  • These forests are disappearing at an alarming rate, a rate at which, if it continues, will eliminate the forests in fewer than ten years.
  • Unlike many other plant seeds, coffee seeds are sensitive to cold and maintain their germination potential for only a couple of months.  Therefore, wild varieties are not candidates for seed banks. They must be preserved growing in the wild.

Although the benefits of preserving genetic resources is widely acknowledged, putting a monetary figure on these resources is difficult. The authors of this paper examined the potential economic benefits of preserving the genetic resources of coffee by looking at several characteristics that are known to occur in wild Ethiopian coffees: resistance to three major coffee pests/diseases, a variety with a lower caffeine content, and a higher yield variety.

They concluded that the economic value of Ethiopian coffee genetic resources is between US$420 million up to $1.45 billion (the variation reflects uncertainty in the coffee markets over the period of time it would take to incorporate wild genes into cultivars).  This does not take into account other beneficial characteristics that might be found in wild coffees, such as heat resistance that will be needed in the face of global climate change.

Current inventories of the genetic diversity in Ethiopian forests are inadequate to determine how much forest needs to be preserved in order to maintain the coffee gene pool, conclude the authors.  Certainly, we do not need to be replacing native forest and wild coffee with large plantations of nursery-grown plants. This paper provides significant economic evidence that preserving Ethiopian forests, and their wild coffee resources, are nearly priceless.