In 2006, a study by Sierra and Russman analyzed the additional conservation obtained through PES, over and above the baseline conservation rate. The study concluded that the PES program definitely affected land use decisions because land owners used the payments for other productive activities thus keeping the forest cover intact. However, they also concluded that this was not the most effective use of funds because the majority of these forests would have remained intact even without the payments. The study suggested that it would a better strategy to engage in the protection of more critical habitats instead.