Macroecology
of Avian Frugivore Diversity
Little
is known about the factors that constrain the broad-scale occurrence
of ecological specialists such as avian frugivores – a guild
of mainly tropical bird species specialized on fleshy–fruited
plants as food resources. In my PhD project, I examined the spatial
distribution of avian frugivores at different spatial scales using
comprehensive species distribution databases and advanced statistical
modelling. I was particularily interested in whether the diversity
of food plants, contemporary climate and energy, or habitat heterogeneity
determine species richness. At a global scale, the distribution of
avian frugivory was best explained by climate, especially water-energy
dynamics, productivity and seasonality, whereas topographic heterogeneity
played a minor role. Cross-continental comparisons indicated that
major biogeographic regions show distinct differences in species diversity
supporting an important role of historical processes in shaping avian
frugivore distribution. Across sub-Saharan Africa, path modeling indicated
that species richness of Ficus trees (their fruits being one
of the major food resources for frugivores in the tropics) had the
strongest direct effect on richness of avian frugivores whereas the
influences of variables related to water-energy and habitat heterogeneity
were mainly indirect. At a regional scale, I showed that not only
trophic interactions but also vegetation structural complexity shapes
the spatial distribution of frugivorous birds. Overall, I demonstrated
the interplay of biotic, environmental, and historical constraints
on bird assembly and species distributions over broad geographic scales.
Keywords:
biogeography, co-evolution, community assembly, macroecology, plant-frugivore
interactions, species-energy theory.
Publications:
- Kissling,
W.D., Rahbek, C. & Böhning-Gaese, K. (2007): Food plant
diversity as broad-scale determinant of avian frugivore richness.
Proceedings of the Royal Society B 274: 799-808. [Abstract
+ free PDF]
- Kissling,
W.D., Field, R. & Böhning-Gaese, K. (2008): Spatial
patterns of woody plant and bird diversity: functional relationships
or environmental effects? Global Ecology and Biogeography
17: 327-339. [Abstract]
- Kissling,
W.D., Böhning-Gaese, K. & Jetz, W. (2009): The global
distribution of frugivory in birds. Global Ecology and Biogeography
18: 150-162. [Abstract]
Figure
- Geographic patterns of avian frugivore species richness in Sub-Saharan
Africa are spatially congruent with those figs (Ficus spp.)
- a keystone plant resource for frugivores in the tropics. A:
Obligate frugivores (92 species). B: Partial frugivores (200
species). C: All Ficus trees (86 species). D:
Opportunistic fruit-eaters (290 species). E: All breeding birds
(1771 species). See Kissling et al. (2007) for more details.
