There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.
Abstract
Although numerous factors are postulated to be responsible for the gradient of increasing
taxon richness towards lower latitudes, it has recently been suggested that the primary
determinant is geographic area. This area model is appealing in its logic, but there
is little empirical evidence to support it and several other mechanisms might also
interact to obscure its effects. Nonetheless, the model has highlighted several fundamental
issues concerning range size, speciation and extinction that, despite their considerable
significance, remain poorly understood.