Ecology & Environmental Science

Climate change and species ranges of wild birds

two carrots on a gridThe extent to which climate change may diminish the efficacy of protected areas is one of today’s most pressing conservation issues. Many projections suggest that the distribution shifts of climate-driven species will leave protected areas impoverished and these species inadequately protected, while other evidence indicates that intact ecosystems within protected areas will be resilient to change.

We used data from an international database of observations of wild birds to show how recent changes in the distribution of 139 Tanzanian bird species are linked to climate change, protected area status and land degradation. The methodology employed was Bayesian species distribution modelling, accounting specifically for both spatial autocorrelation and detection probability, the latter using information on sampling effort recorded for each survey.

Our results indicated that protected area status tends to be associated with lower local extinction and higher colonisation rates. This suggests that the continued maintenance of existing protected areas is an appropriate conservation response to the challenge of climate and environmental change.

Plot showing predicted presence probability of Fischer’s sparrow-lark (Eremopterix leucopareia), as size of square, for two modelling situations: (a) where the modelling does not take account of observer effort; and, (b) where it does. Squares coloured red correspond to actual sightings; those coloured black indicate no sighting was made (possibly due to zero or low effort). The background green shades represent the proportion of savannah habitat in the square (higher for darker shades). Protected areas are also marked. It can be seen that not accounting for observer effort leads to a severe underestimation of population range in the southern areas where observer effort was lower.

presence probability map Plot showing predicted presence probability of Fischer’s sparrow-lark (Eremopterix leucopareia), as size of square, for two modelling situations: (a) where the modelling does not take account of observer effort; and, (b) where it does. Squares coloured red correspond to actual sightings; those coloured black indicate no sighting was made (possibly due to zero or low effort). The background green shades represent the proportion of savannah habitat in the square (higher for darker shades). Protected areas are also marked. It can be seen that not accounting for observer effort leads to a severe underestimation of population range in the southern areas where observer effort was lower.

Further details from: Mark Brewer

Article date 2015

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