Geographical patterns for relict and young species of birds in Africa and South America and implications for conservation priorities

Fjeldså, Jon

doi:10.1007/bf00055939

Cited by 276 publications

(299 citation statements)

References 39 publications

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“…Stability may increase species richness as more stable areas may have more speciation events and thus higher richness (Stephens & Wiens, 2003), as suggested by positive correlations between stability and the number of recently evolved avian endemics in Africa and South America (Fjeldså, 1994). Stability may also increase the time available for re-colonisation and thus species richness, e.g.…”

Section: (2 ) Seasonalitymentioning

confidence: 99%

Species–energy relationships at the macroecological scale: a review of the mechanisms

2005

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Correlations between the amount of energy received by an assemblage and the number of species that it contains are very general, and at the macro-scale such species-energy relationships typically follow a monotonically increasing curve. Whilst the ecological literature contains frequent reports of such relationships, debate on their causal mechanisms is limited and typically focuses on the role of energy availability in controlling the number of individuals in an assemblage. Assemblages from high-energy areas may contain more individuals enabling species to maintain larger, more viable populations, whose lower extinction risk elevates species richness. Other mechanisms have, however, also been suggested. Here we identify and clarify nine principal mechanisms that may generate positive species-energy relationships at the macro-scale. We critically assess their assumptions and applicability over a range of spatial scales, derive predictions for each and assess the evidence that supports or refutes them. Our synthesis demonstrates that all mechanisms share at least one of their predictions with an alternative mechanism. Some previous studies of species-energy relationships appear not to have recognised the extent of shared predictions, and this may detract from their contribution to the debate on causal mechanisms. The combination of predictions and assumptions made by each mechanism is, however, unique, suggesting that, in principle, conclusive tests are possible. Sufficient testing of all mechanisms has yet to be conducted, and no single mechanism currently has unequivocal support. Each may contribute to species-energy relationships in some circumstances, but some mechanisms are unlikely to act simultaneously. Moreover, a limited number appear particularly likely to contribute frequently to species-energy relationships at the macro-scale. The increased population size, niche position and diversification rate mechanisms are particularly noteworthy in this context.

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Section: (2 ) Seasonalitymentioning

confidence: 99%

Species–energy relationships at the macroecological scale: a review of the mechanisms

2005

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“…The study of geographic speciation patterns in the tropics has traditionally focused on the lowlands, the area often viewed as the main centre of historical species proliferation, and numerous mechanisms, such as the refuge hypothesis (Haffer 1969;Whitmore & Prance 1987), have been proposed to explain the patterns of species distributions we see today (Haffer 1997). However, recent evidence from Afrotropical and Neotropical birds that young species predominantly occur in montane areas, and old species in lowland areas (Fjeldså 1994), suggests that the tropical montane regions of the world may more frequently be acting as the 'species pumps', with the lowlands functioning in part as 'museums', where dispersed older species accumulate (Fjeldså 1994;Fjeldså & Lovett 1997;Roy et al 1997). Clearly, being able to distinguish between speciation centres and areas of species accumulation has considerable implications for several fields, particularly conservation (Fjeldså 1994).…”

Section: Introductionmentioning

confidence: 99%

“…However, recent evidence from Afrotropical and Neotropical birds that young species predominantly occur in montane areas, and old species in lowland areas (Fjeldså 1994), suggests that the tropical montane regions of the world may more frequently be acting as the 'species pumps', with the lowlands functioning in part as 'museums', where dispersed older species accumulate (Fjeldså 1994;Fjeldså & Lovett 1997;Roy et al 1997). Clearly, being able to distinguish between speciation centres and areas of species accumulation has considerable implications for several fields, particularly conservation (Fjeldså 1994).…”

Section: Introductionmentioning

confidence: 99%

Montane speciation patterns in Ithomiola butterflies (Lepidoptera: Riodinidae): are they consistently moving up in the world?

Hall

2005

Proc. R. Soc. B.

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Tropical lowland areas have often been seen as the centres of terrestrial species proliferation, but recent evidence suggests that young species may be more frequent in montane areas. Several montane speciation modes have been proposed, but their relative frequencies and predominant evolutionary sequence remain unclear because so few biogeographic and phylogenetic studies have tested such questions. I use morphological data to generate a phylogenetic hypothesis for all 11 species of the riodinid butterfly genus Ithomiola (Riodininae: Mesosemiini: Napaeina). These species are shown here to be all strictly geographically and elevationally allo-or parapatrically distributed with respect to their closest relatives in lowland and montane regions throughout the Neotropics. The overwhelming pattern in Ithomiola is of repeated upward parapatric speciation across an elevational gradient, and the genus appears to provide the clearest example to date of vertical montane speciation. All of the young derived species are montane and all of the old basal species are confined to the lowlands, supporting the hypothesis of montane regions largely as 'species pumps' and lowland regions as 'museums'. Possible reasons for the post-speciation maintenance of parapatric ranges in Ithomiola are discussed.

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“…Using another approach Fjeldså and coworkers (Fjeldså, 1993(Fjeldså, , 1994Fjeldså & Lovett, 1997) used genetic distance based on the DNA/DNA hybridization data to distinguish areas where ancient species persist from those where diversification is more intense or recent. Moreover, BirdLife International investigated areas where narrowly endemic birds congregate in Endemic Bird Areas (Stattersfield et al, 1998) and developed maps of avian biomes across all of Africa for their Important Bird Area project (Fishpool & Evans, 2001).…”

Section: Introductionmentioning

confidence: 99%

Biogeographical patterns of endemic terrestrial Afrotropical birds

Klerk

Crowe

Fjeldså

et al. 2002

Diversity and Distributions

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Abstract.Biogeographical zones are described for terrestrial bird species endemic to the Afrotropics using up-to-date distributional data and multivariate statistical techniques. This provides an objective basis for a hierarchy of subregions, provinces and districts, based on a set of rules. Results are compared to previous studies at continental and regional scales. Biogeographical zones for passerines and non-passerines are compared and found to be similar. Peaks of species richness and narrow endemism are described for the six major subdivisions (subregions) identified by the cluster analysis. Coincidence of peaks of species richness and narrow endemism is found to be low, such that areas selected to represent high species richness tallies will often fail to represent narrow endemics. Strong regionalization of Afrotropical birds indicates the need to use a biogeographical framework in conservation priority setting exercises to ensure that unique, but species-poor, avifaunas are not neglected.

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Geographical patterns for relict and young species of birds in Africa and South America and implications for conservation priorities

Cited by 276 publications

References 39 publications

Species–energy relationships at the macroecological scale: a review of the mechanisms

Species–energy relationships at the macroecological scale: a review of the mechanisms

Montane speciation patterns in Ithomiola butterflies (Lepidoptera: Riodinidae): are they consistently moving up in the world?

Biogeographical patterns of endemic terrestrial Afrotropical birds

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