Scattered trees: a complementary strategy for facilitating adaptive responses to climate change in modified landscapes?
Facilitating adaptive responses of organisms in modified landscape will be essential to overcome the negative effects of climate change and its interaction with land use change. Without such action, many organisms will be prevented from achieving the predicted range shifts they need to survive. Scattered trees are a prominent feature of many modified landscapes, and could play an important role in facilitating climate change adaptation. They are keystone structures because of the disproportionally large ecological values and ecosystem services that they provide relative to the area they occupy in these landscapes. The provision of habitat and connectivity will be particularly relevant. Scattered trees are declining in modified landscapes due to elevated tree mortality and poor recruitment often associated with intensive land use. The continuing global decline of scattered trees will undermine the capacity of many organisms to adapt to climate change. Synthesis and applications. The sustainable management of scattered trees in modified landscapes could complement other strategies for facilitating climate change adaptation. They create continuous, though sparse, vegetation cover that permits multi-directional movements of biota across landscapes and ecological networks. They have the capacity to span ecosystems and climatic gradients that cannot be captured in formal reserves alone. The management of scattered trees should be an integral part of conservation objectives and agricultural activities in modified landscapes. Public investment, through mechanisms such as agri-environmental schemes, in rotational grazing, temporary set-asides, tree-planting and regulations that reduce clearing and early mortality among standing trees will improve the capacity of biota to adapt to climate change.