Corridor

		CORRIDOR

		Working group on evaluation and synthesis of information on tree cover to balance productivity and biodiversity in agricultural landscapes along the Mesoamerican Biological Corridor

Key findings


	Trees are associated with changes in productivity and biodiversity in both coffee and pasture systems. There was a suggestion that low levels of tree cover (<20%) favoured productivity of animals on pastures, and that in general higher levels of tree cover (>20%) favoured biodiversity of key forest taxa in both pastures and coffee, indicating the existence of trade-offs between agricultural productivity and biodiversity. Constraints in defining and exploring these trade-offs more fully included:


	1. There were many individual published studies of tree cover, biodiversity and productivity for pastures and coffee systems in Central America (over 400 published articles) but they were mainly conducted in one or two countries at either end of the MBC, concentrated on a few plant and animal taxa and were rarely integrated.


	2. There were virtually no measurements of pasture productivity in the region because standing biomass rather than growth was assessed and there were no discernible overall relationships between tree cover and coffee productivity because tree shade (that varies seasonally) was not comparatively measured nor were management variations controlled for.


	3. Meta analyses of species responses to tree cover in pastures and coffee systems were precluded, even for taxa where there were many studies, because of differences in sampling methods and intensities used in different studies.


	4. For both pasture and coffee systems, there were very few places where biodiversity and productivity had been measured simultaneously, allowing direct assessment of trade-offs and synergies.

	5. While biodiversity measurements in coffee were often located in proximity to remaining forest cover, those in pasture were not, and so it was difficult to assess from existing information the contribution of trees to habitat connectivity in the coffee, pasture and forest land use mosaics, that presently make up the key parts of the forest corridor where connectivity is required. See Technical reports page for more details.