Gains and losses of birds restricted to Mexico since 1950. Squares show sampled areas from which patterns were interpolated. Green indicates low values, red indicates high values.

SOURCE: Peterson et al. (2015) Sci. Adv. 1: e1400071.

Bird ranges are shifting in response to climate change (Zuckerberg et al. 2009, Auer & King 2014, Environmental Protection Agency 2014, Virkkala & Lehikoinen 2014, Gillings et al. 2015), and whilst considerable species turnover is expected by the end of the century (Hole et al. 2009, Stralberg et al. 2009, Bagchi et al. 2013, Velasquez-Tibata et al. 2013), changes in Mexican avian composition can already be seen (Peterson et al. 2015).

Historical and current Mexican bird range distributions were used to determine the relationship between avifaunal change, human activity and climate change (Peterson et al. 2015). A human impact index incorporated data on nine variables including human population pressure, land use and infrastructure (human population density and distribution of night time lighting, roads and railways), whilst climate change data included average temperature and total annual precipitation.

The biases inherent to large-scale monitoring projects—such as data concentrated in easy to access areas—was overcome by using a modelling approach that used the range of the existing data to evenly fill the gaps.

Of 115 endemic species studied, there were substantially more endemic species that have been lost than gained, with changes being largely driven by temperature change. The patterns of losses, gains and species turnover varied spatially, with losses being wide spread, but gains being concentrated in just two hotspots.  Climate change has therefore had large impacts on avian range dynamics over the past century, with profound effects on avian composition in Mexico.

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.