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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    ABSTRACT: The management of multi-functional landscapes warrants better knowledge of environment-richness associations at varying disturbance levels and habitat gradients. Intensive land-use patterns for agricultural purposes lead to fragmentation of natural habitat resulting in biodiversity loss that can be measured using landscape metrics to assess mammalian richness. Since carnivores and herbivores are likely to show different responses to disturbance, we calculated carnivore, non-carnivore, and total mammal species richness from camera surveys using a first order Jackknife Estimator. Richness was compared along a habitat gradient comprising coastal forest, Acacia thicket, and highland in KwaZulu-Natal, South Africa. We used standardized OLS regression models to identify climatic and disturbance variables, and landscape metrics as predictors of species richness. The estimated total and non-carnivore species richness were highest in coastal forest, while carnivore species richness was highest in highland followed by coastal forest and Acacia thicket. Average monthly maximum temperature was a significant predictor of all richness groups, and precipitation of the wettest month and isothermality determined total and non-carnivore species richness, respectively. These climatic variables possibly limit species distribution because of physiological tolerance of the species. Total mammal richness was determined by mean shape (+) and habitat division (−) while diversity (+) and patch richness (−) explained carnivore species richness. Mean shape index (+) influenced non-carnivore richness. However, habitat division and patch richness negatively influenced total mammal richness. Though habitat patch size and contiguity had a weak positive prediction, these metrics demonstrated the importance of habitat connectivity for maintaining mammal richness. The identification of these climatic and landscape patterns is important to facilitate future landscape management for mammal conservation in forest-mosaics.
    Ecological Indicators 08/2016; 60:385-393. DOI:10.1016/j.ecolind.2015.07.011 · 3.44 Impact Factor
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    • "Another 16 families are mostly frugivores (Jordano 2000; Kissling, et al. 2012; Wenny, et al. in press), however only a few species are exclusively frugivorous (Izhaki and Safriel 1989; Jordano 2000; Wenny, et al. in press). Fruits are such a key resource for birds that the diversity of fruiting plants may play a role in determining avian diversity (Kissling, et al. 2007). In tropical and subtropical forests, figs (Ficus spp.) are particularly important and eaten by over 1,200 species of birds in 92 families, including birds that are typically carnivorous. "
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    ABSTRACT: Birds are ubiquitous and highly interactive members of forest communities. As insect predators, birds influence tree growth by reducing the effect of folivorous arthropods. Coffee plantations, for example, benefit from insectivorous birds and have increased productivity as a result of bird control of insect pests. As frugivores that can move large distances, birds are the most important seed dispersers in tropical forests. Many crows and jays play critical roles as nut dispersers in temperate forests. Large vertebrate predators, such as hawks, may affect seedling establishment by preying on scatter-hoarding mammals or affecting their behavior. Pollination by birds is an important element in influencing the genetic structure of tree populations. Many of these ecosystem functions vary by latitude and by season. In return, forests provide food, nesting sites, and, in some cases, thermal refugia for birds. Forest structure, particularly in tropical sites, is closely tied to avian species richness on local and regional scales. Major threats to forest birds include deforestation, forest fragmentation, and urbanization. Invasive predators on nests and adults are also an important threat to island birds and climate-related changes.
    Handbook of Forest Ecology, Edited by Richard Corlett, Kelvin Peh, Yves Bergeron, 12/2015: chapter Birds in Forest Ecosystems: pages 281-296; Routeledge Press.
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    • "To investigate whether guild composition differed between sun and shade coffee, we classified birds into guilds (i.e., insectivore, granivore, frugivore, nectarivore, or omnivore) based on the first and second major diet preferences following Kissling et al. (2007). We then re-classified 12 species (mostly Sunbirds: Nectariniidae to either nectarivores or omnivores) based on our own foraging observations and published data from East Africa (Borghesio and Laiolo, 2004; Ndang'ang'a et al., 2013). "
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    ABSTRACT: Agricultural expansion to meet rising crop demand is one of the greatest threats to terrestrial biodiversity. Coffee, one of the most valuable trade items in tropical countries, can provide both economic livelihood and wildlife habitat. Previous work, conducted primarily on Neotropical coffee farms, indicates that birds are generally more abundant and diverse in farms with a canopy of shade trees, though regional variation exists. To date, few studies have examined birds on coffee farms in Africa, which contains 20% of the world's coffee acreage. We studied differences in the bird communities between sun and shade monoculture coffee in central Kenya, and we examined effects of vegetation on bird abundance and diversity. Sun coffee had higher species richness and abundances of all major guilds (omnivores, insectivores, and granivores), and showed low community similarity to shade. Unlike findings from the Neotropics, canopy cover appeared to have a negative influence on all guilds, while understory volume of weeds increased bird abundance and species richness with a similar magnitude as canopy cover. These differences highlight the need for further studies in the general East Africa region with a wider variety of shade coffee systems.
    Global Ecology and Conservation 09/2015; DOI:10.1016/j.gecco.2015.09.004
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