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.