Bioscience
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Bird dietary guild richness across latitudes, environments and biogeographic regions
Article first published online: 27 MAY 2011
DOI: 10.1111/j.1466-8238.2011.00679.x
© 2011 Blackwell Publishing Ltd
Additional Information
How to Cite
Kissling, W. D., Sekercioglu, C. H. and Jetz, W. (2012), Bird dietary guild richness across latitudes, environments and biogeographic regions. Global Ecology and Biogeography, 21: 328–340. doi: 10.1111/j.1466-8238.2011.00679.x
Publication History
- Issue published online: 9 FEB 2012
- Article first published online: 27 MAY 2011
Keywords:
- Aves;
- biogeography;
- birds;
- ecology;
- food;
- guild assembly;
- niche;
- species diversity;
- species–energy theory;
- tropics
ABSTRACT
Aim To integrate dietary knowledge and species distributions in order to examine the latitudinal, environmental, and biogeographical variation in the species richness of avian dietary guilds (herbivores, granivores, frugivores, nectarivores, aerial insectivores, terrestrial/arboreal insectivores, carnivores, scavengers, and omnivores).
Location Global.
Methods We used global breeding range maps and a comprehensive dietary database of all terrestrial bird species to calculate guild species richness for grid cells at 110 × 110 km resolution. We assessed congruence of guild species richness, quantified the steepness of latitudinal gradients and examined the covariation between species richness and climate, topography, habitat diversity and biogeographic history. We evaluated the potential of current environment and biogeographic history to explain global guild distribution and compare observed richness–environment relationships with those derived from random subsets of the global species pool.
Results While most guilds (except herbivores and scavengers) showed strong congruence with overall bird richness, covariation in richness between guilds varied markedly. Guilds exhibited different peaks in species richness in geographical and multivariate environmental space, and observed richness–environment relationships mostly differed from random expectations. Latitudinal gradients in species richness were steepest for terrestrial/arboreal insectivores, intermediate for frugivores, granivores and carnivores, and shallower for all other guilds. Actual evapotranspiration emerged as the strongest climatic predictor for frugivores and insectivores, seasonality for nectarivores, and temperature for herbivores and scavengers (with opposite direction of temperature effect). Differences in species richness between biogeographic regions were strongest for frugivores and nectarivores and were evident for nectarivores, omnivores and scavengers when present-day environment was statistically controlled for. Guild richness–environment relationships also varied between regions.
Main conclusions Global associations of bird species richness with environmental and biogeographic variables show pronounced differences between guilds. Geographic patterns of bird diversity might thus result from several processes including evolutionary innovations in dietary preferences and environmental constraints on the distribution and diversification of food resources.