Fig. 1 Google Earth image of Yayu biosphere reserve.
Site Description
Yayu coffee forest is a National Forest Priority Area, intended for biodiversity conservation and protection of coffee genetic resources. It was decided the most effective method for managing sustainable use of the forest was to establish a biosphere reserve. In 2010, the Yayu Biosphere Reserve was awarded UNESCO world heritage status, due to the genetic value of the Coffea arabica varieties present in the core zone. Over ten years of research has occurred in this area, primarily by the Center for Development Research (ZEF) at the University of Bonn and continued by ECFF. We had to keep this in mind when designing our study as these communities have had considerable scrutiny already.
The biosphere encompasses two weredas (Yayu and Doraani), where we are working in 5 and 4 kebeles respectively.
Yayu coffee forest is a National Forest Priority Area, intended for biodiversity conservation and protection of coffee genetic resources. It was decided the most effective method for managing sustainable use of the forest was to establish a biosphere reserve. In 2010, the Yayu Biosphere Reserve was awarded UNESCO world heritage status, due to the genetic value of the Coffea arabica varieties present in the core zone. Over ten years of research has occurred in this area, primarily by the Center for Development Research (ZEF) at the University of Bonn and continued by ECFF. We had to keep this in mind when designing our study as these communities have had considerable scrutiny already.
The biosphere encompasses two weredas (Yayu and Doraani), where we are working in 5 and 4 kebeles respectively.
Fig. 2 Schematic of sampling strategy across elevation and patch size.
Sampling Design
The Yayu Biosphere Reserve and the surrounding communities cover an elevation range from approx. 1200 m to 1800 m. Also, in contrast to our site in Kakum, the land cover outside of the reserve is patchy with areas of tree cover of various sizes. As Coffea arabica is predicted to suffer with increased temperatures due to climate change, we thought it important to look at coffee yields along an elevation gradient. At each elevation we sampled along a management/shade gradient and a relative patch size measure, to see if placement in a larger forest patch and with greater shade provides some ecosystem service benefits to the coffee. In order to get three replicates of each treatment and at least two reference core forest plots, we established 56 plots, overlapping with ~80 farms.
The Yayu Biosphere Reserve and the surrounding communities cover an elevation range from approx. 1200 m to 1800 m. Also, in contrast to our site in Kakum, the land cover outside of the reserve is patchy with areas of tree cover of various sizes. As Coffea arabica is predicted to suffer with increased temperatures due to climate change, we thought it important to look at coffee yields along an elevation gradient. At each elevation we sampled along a management/shade gradient and a relative patch size measure, to see if placement in a larger forest patch and with greater shade provides some ecosystem service benefits to the coffee. In order to get three replicates of each treatment and at least two reference core forest plots, we established 56 plots, overlapping with ~80 farms.
Plot Design
Due to the number of plots we established, it was not logistically realistic to set up fifty-six 60 m by 60 m plots. Instead, we chose as subset of plots (14) for full tree census, similar to our cocoa plots. While in every plot, we focused on a 20 m by 20 m sub-plot where 7 coffee shrubs were monitored at regular intervals throughout the flowering and fruit maturation process (see Methods).
Due to the number of plots we established, it was not logistically realistic to set up fifty-six 60 m by 60 m plots. Instead, we chose as subset of plots (14) for full tree census, similar to our cocoa plots. While in every plot, we focused on a 20 m by 20 m sub-plot where 7 coffee shrubs were monitored at regular intervals throughout the flowering and fruit maturation process (see Methods).