Deforestation in the Brazilian Amazon is occurring at alarming rates and is resulting in heavily fragmented landscapes (Lindquist et al. 2012). This threat will be exacerbated by climate change, as species ranges shift in response to changing climatic conditions (Huntley et al. 2008, Hole et al. 2009, Barbet-Massin et al. 2009, Doswald et al. 2009, Huntley et al. 2012, Bagchi et al. 2013, Langham et al. 2015). The difficulties of dispersing across matrices of unsuitable habitat in fragmented landscapes may in part be alleviated by the creation of forested corridors.

The benefits of habitat corridors for avian diversity was determined in the Brazilian Amazon using 37 riparian corridors (Lees and Peres 2008). Corridors were either connected to habitat patches, unconnected or control patches within undisturbed forest. A total of 365 bird species were recorded in the study period with species specific responses to corridors being commonplace.

Primary forest sensitive species were positively associated with corridorwidth, the size of the source forest patch and the forest basal area. Less sensitive species were negatively affected by canopy cover but positively by source patch size and the abundance of mauritia palm (an important food source of some species). Large forest patches held over 60% more species than unconnected and narrow corridors.

The benefit of forest corridors appears therefore to depend mainly on how closely it mimics the connecting habitat and requirements of the species in question. Generally, habitat corridors will benefit habitat generalists over specialists, as corridors are unlikely to match the requirements of multiple highly specialized species.

The number of species to benefit from habitat corridors varies greatly between studies, with just 28% of 76 species (across tropics and temperature regions) experiencing increased occurrence or abundance (Pearce-Higgins and Green 2014). Corridor quality will be important in ensuring effective connectivity between habitat patches for some species, and willikely prove an important approach in climate change adaptation.

This case study is taken from ‘The Messengers: What birds tell us about threats from climate change and solutions for nature and people’. To download the report in full click here.