Projected species turnover of Californian birds by 2070. Colours represent dissimilarity between current and future avian community composition, based on the probability of occurrence for 60 focal species.

SOURCE: Stralberg, D. et al. (2009) Re-shuffling of species with climate disruption: A no-analog future for california birds? PLoS ONE 4: e6825.

Species ranges are shifting in response to climate change (Zuckerberg et al. 2009, Auer & King 2014, National Audubon Society 2014, Virkkala & Lehikoinen 2014, Gillings et al. 2015), and this is expected to continue throughout the century (Huntley et al. 2008, Barbet-Massin et al. 2009, Hole et al. 2009, Araujo et al. 2011, Bagchi et al. 2013, Langham et al. 2015). These shifts are likely to result in new avian community compositions (Bagchi et al. 2013, Hole et al. 2009) and entirely novel avian assemblages are expected in California by the end of the century as species respond to changing climatic conditions (Stralberg et al. 2009). This is likely to have profound effects on ecosystem functioning.

Avian distribution models, climate projections and vegetation distribution data were combined to determine the degree of avian community change for 60 focal species across California, North America (Stralberg et al. 2009).

Depending on the climatic projection and the scale at which a community was defined, completey novel avian assemblages were predicted to cover between 10-57% of California’s land area by 2070. Species turnover was also predicted to occur in regions predicted to retain species, resulting in new, but not completely novel avian compositions. These areas were mainly mountainous regions such as the northern Sierra Nevada foothills.

Novel and altered assemblages could have severe impacts on ecosystem processes, especially since many species may be shifting into unsuitable habitat due to anthropogenic large scale land transformation. Flexible and adaptive management will be vital, as decisions will need to be made on which species or habitats to prioritise efforts and funds.

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.