Resurgence of specialized shade coffee cultivation: Effects on pollination services and quality of coffee production

Since the early 2000s, there has been a resurgence in shade coffee production on the island of Puerto Rico. The newly restored specialized shade canopy consists of four native tree species, three of which are nitrogen fixers, and is intended to provide 30% shade cover once the trees are matured. Though much is known about the benefits of rustic and traditional shade plantations to coffee production, there is little information available for specialized shade plantations. Here, we investigate the ways in which fruit set, seed predation, bean weight, proportion of peaberries (i.e., malformed fruits), and beverage quality differ between sun and specialized shade plantations of Coffea arabica and Coffea canephora. Additionally, to assess whether coffee plants were pollen limited, we conducted a pollen supplementation experiment in which we compared pollen deposition and berry production on hand-pollinated branches to those of naturally, open-pollinated ones. We found that there was no evidence of pollen limitation on fruit set between sun and specialized shade plantations of C. arabica or C. canephora. We found that specialized shade benefits the proportion of C. arabica fruit set, without compromising bean weight or the proportion of peaberries produced. In comparison, C. canephora showed no improvement in the proportion of fruits set with specialized shade; however, beans from open-pollinated flowers weighed more in specialized shade than sun. Beverage quality was marginally better under shade, and for hand-pollinated flowers. Our results add to the limited body of work investigating the benefits of specialized shade coffee plantations on ecosystem services.