University of Michigan researchers Shalene Jha and Christopher Dick discovered that native trees have more genetic diversity in the coffee plantations than they do in other parts of the forest, and that's a very good thing. From the Science Daily article:
A concern in agricultural areas is that increasingly fragmented landscapes isolate native plant populations, eventually leading to lower genetic diversity. But this study shows that shade coffee farms, by being hospitable to birds, support widespread dispersal of native trees, in effect connecting patches of surrounding forest.So, long story short, drink shade grown beans. It's the only way to brew.
In addition, shade coffee farms may serve as reservoirs for future forest regeneration, as the farms typically fall out of production in less than a century. Given that potential---as well as their roles in connecting habitat patches, preserving genetic diversity and sheltering native wildlife---it is important to encourage this traditional style of agriculture, Jha said.