Impacts of climate change on the terrestrial ecosystems of Madeira

Climate change can have severe effects on the natural environment, including water resources and ecosystems. Islands are unique systems more vulnerable to climate change than continental areas. Madeira, an Atlantic subtropical island, has a quite unique flora and fauna and is considered a Mediterranean biodiversity 'hot-spot'. The lower altitudes of Madeira are predominantly occupied by urban areas and agricultural crops; exotic forest plantations are widespread at low- to mid-altitudes. The native forest, Laurissilva, an extremely important and rare ecosystem, occurs up to 1450 m and is replaced in higher altitudes by heaths and other altitude vegetation. The CLIMAT project investigated the impact of climate change in Madeira ecosystems. Using global circulation models downscaled to Madeira, we produced climatic scenarios for 2040-2069 and 2070-2099. Subsequently, we generated future scenarios for hydrology, forest, agriculture, and biodiversity sectors. Future climatic scenarios project reduced rainfall and higher average temperatures across Madeira. The potentially suitable area for the main agricultural crops is expected to expand in altitude. Suitable area for the exotic forests and the Laurissilva is expected to increase as the expansion in altitude will be greater than the retraction in lower reaches. The suitable climatic range for heaths will suffer a severe reduction: it is expected to retract in lower reaches but cannot expand in altitude because it is predominantly in the higher elevations already. These shifts in habitat distributions may translate into large changes in ecosystem services supply. Altitude species, including endemic and rare ones, may suffer range reductions or even disappear. We discuss adaptation measures that should be taken into account in future conservation plans.