Food plant diversity as broad-scale determinant of avian frugivore richness

Community and Macroecology Group, Department of Ecology, Institute of Zoology, Johannes Gutenberg-University, 55099 Mainz, Germany.
Proceedings of the Royal Society B: Biological Sciences (Impact Factor: 5.05). 04/2007; 274(1611):799-808. DOI: 10.1098/rspb.2006.0311
Source: PubMed


The causes of variation in animal species richness at large spatial scales are intensively debated. Here, we examine whether the diversity of food plants, contemporary climate and energy, or habitat heterogeneity determine species richness patterns of avian frugivores across sub-Saharan Africa. Path models indicate that species richness of Ficus (their fruits being one of the major food resources for frugivores in the tropics) has the strongest direct effect on richness of avian frugivores, whereas the influences of variables related to water-energy and habitat heterogeneity are mainly indirect. The importance of Ficus richness for richness of avian frugivores diminishes with decreasing specialization of birds on fruit eating, but is retained when accounting for spatial autocorrelation. We suggest that a positive relationship between food plant and frugivore species richness could result from niche assembly mechanisms (e.g. coevolutionary adaptations to fruit size, fruit colour or vertical stratification of fruit presentation) or, alternatively, from stochastic speciation-extinction processes. In any case, the close relationship between species richness of Ficus and avian frugivores suggests that figs are keystone resources for animal consumers, even at continental scales.

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    • "The use of species richness models at smaller spatial scales is now benefiting local conservation actions. Other potential determinants of species richness include food availability, trophic interactions, predator pressure, hunting for bush meat and traditional medicine and expansion of invasive predators such as feral dogs and cats (Hawkins and Porter, 2003; Karanth et al., 2004; Kissling et al., 2007; Jetz et al., 2009; Greve et al., 2012; Kiffner et al., 2015). Previous assessments on the distribution of mammalian biodiversity in South Africa relied on secondary sources such as range maps (Siegfried and Brown, 1992; Freitag and Van Jaarsveld, 1995) and museum specimen records (Gelderblom et al., 1995; Mugo et al., 2005; Rowe-Rowe and Taylor, 1996). "
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