Biogeology of Wallacea: geotectonic models, areas of endemism, and natural biogeographical units

Abstract

The concepts of biogeographical regions and areas of endemism are briefly reviewed prior to a discussion of what constitutes a natural biogeographical unit. It is concluded that a natural biogeographical unit comprises a group of endemic species that share a geological history. These natural biogeographical units are termed Wallacean biogeographical units in honour of the biogeographer A.R. Wallace. Models of the geological development of Indonesia and the Philippines are outlined. Areas of endemism within Wallacea are identified by distributional data, and their relationship to each other and to the adjacent continental regions are evaluated using molecular phylogenies from the literature. The boundaries of these areas of endemism are in broad agreement with earlier works, but it is argued that the Tanimbar Islands are biologically part of south Maluku, rather than the Lesser Sundas, and that Timor (plus Savu, Roti, Wetar, Damar, and Babar) and the western Lesser Sundas form areas of endemism in their own right. Wallacean biogeographical units within Wallacea are identified by congruence between areas of endemism and geological history. It is concluded that although Wallacea as a whole is not a natural biogeographical region, neither is it completely artificial as it is formed from a complex of predominantly Australasian exotic fragments linked by geological processes within a complex collision zone. The Philippines are argued to be an integral part of Wallacea, as originally intended. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101, 193–212.

Biogeographical modules and island roles: a comparison of Wallacea and the West Indies

“…, 2001; Jønsson et al. , 2008, 2010; Carstensen & Olesen, 2009; Michaux, 2010) and the West Indies (Bond, 1948; Hedges, 1996; Trejo‐Torres & Ackerman, 2001; Vázquez‐Miranda et al. , 2007; Presley & Willig, 2008; Ricklefs & Bermingham, 2008; Willig et al.…”

Tropical Asian species show that the Old World clade of ‘spiny solanums’ (SolanumsubgenusLeptostemonum pro parte: Solanaceae) is not monophyletic

“…This focused on the relationships of African and Malagasy spiny solanums. With the western Pacific, the region is well known as a centre of marine and terrestrial biodiversity (Michaux, 2010) and distribution patterns there have long intrigued biologists (e.g. Parenti & Ebach, 2010;Hall, 2012).…”

Determinants of bird species richness, endemism, and island network roles in Wallacea and the West Indies: is geography sufficient or does current and historical climate matter?

“…For Wallacea, we used Australia, New Guinea, and Borneo as potential extra-Wallacean colonization “mainland” sources (Carstensen and Olesen 2009; Michaux 2010; Jønsson et al 2012), whereas for the West Indies, we used North America, Central, and South America as mainland sources. Isolation effects may also depend on the distance to large source islands within an archipelago.…”

“…For all analysis, MAP, MAT anomaly, and MAT/MAP velocities were Log 10 -transformed, whereas MAT and MAP anomaly were untransformed. Due to the geographic extent of the datasets, we did not attempt to estimate other historical factors that may also potentially affect contemporary bird distributions, such as plate tectonics, volcanic history, island age, or Pleistocene sea-level changes (Murphy et al 2004; Dalsgaard et al 2007; Kreft et al 2008; Presley and Willig 2008; Ricklefs and Bermingham 2008; Whittaker et al 2008; Michaux 2010; Lohman et al 2011; Jønsson et al 2012). Hence, our analyses take the pre-Quaternary diversity and distribution as a given and asks how these have responded to subsequent climate change.…”