The level of diet specialization has a significant impact on spatial distribution of bird species. This is because diet specialization is correlated with a species' overall risk of extinction and can profoundly affect ability of birds to disperse and colonize.
Study of Morelli's team, recently published in the Journal of Biogeography, aimed to identify the key factors that influence the distribution range of avian species on a global scale. Findings based on the analysis of the worldwide distribution range of 7416 species (67% of known bird species) demonstrate that the global range in which bird species live is negatively associated with their specialization in the diet. On the other hand, bigger range positively associates with body mass and evolutionary uniqueness of birds.
Overall, diet specialist species displayed a distribution range of 60% smaller than generalist species. These significant findings underscore the critical impact of species' dietary specialization on their survival and ability to expand into new areas. This global evidence provides new insights for enhancing conservation efforts, particularly for more vulnerable species - avian specialists.
Citation: Benedetti, Y., & Morelli, F. (2024). Global distribution range of birds is negatively correlated with their level of diet specialization. Journal of Biogeography, 00, 1–8.
https://doi.org/10.1111/jbi.14970