Peninsular patterns in biological diversity: historical arrangement, methodological approaches and causal processes

Abstract

Prior research has indicated that peninsula(r) effects appear to be idiosyncratic, depending on context, taxa, scales, and taxonomic levels. In this review (87 papers; 1950 to 2013) I report a historical arrangement of causal processes inducing diversity patterns that may be grouped as: (1) recent stochastic processes (equilibrium and derived island biogeography theories); (2) historical events (palaeoclimatic and palaeogeographic changes); (3) recent deterministic processes with a geographical base–tip gradient; and (4) anthropogenic recent processes. Patterns in species diversity have also been reported for ecological habitat peninsulas on the mainland. Here, mainly anthropogenic causal mechanisms at landscape/patch scale may be hypothesized, with implications in multiscale conservation strategies and applied biogeography. Peninsular studies must overcome weaknesses in methodological approaches regarding the definition of peninsular border and scales, the procedures of setting data and analyses, inadequate data and taxonomic uncertainty, and standardized sampling efforts.

Keywords:

• patterns
• processes
• habitat peninsulas
• alpha diversity
• gamma diversity

Acknowledgements

This work was started more than 15 years ago by Longino Contoli of the Evolutionistic Genetic Centre of National Research Centre (CNR Italy), as part of the eco-biogeographic research programme entitled ‘Origin and evolution of biological diversity and ecological complexity’. I would like to thank Longino Contoli and Marzio Zapparoli for their critical analysis of the draft. I am also grateful to Alessandro Zocchi for his thorough English revision of the manuscript and the Co-Editor (Journal of Natural History) Louise Allcock. Three reviewers (two of them anonymous) largely improved a first draft of the manuscript. Among them, I particularly appreciate the contribution of Dave Jenkins (University of Central Florida), a peninsular researcher and ‘inhabitant’ (as the author), who added a large number of useful and original comments.