Biogeography and Biotic Assembly of Indo-Pacific Corvoid Passerine Birds

Abstract

The archipelagos that form the transition between Asia and Australia were immortalized by Alfred Russel Wallace's observations on the connections between geography and animal distributions, which he summarized in what became the first major modern biogeographic synthesis. Wallace traveled the island region for eight years, during which he noted the marked faunal discontinuity across what has later become known as Wallace's Line. Wallace was intrigued by the bewildering diversity and distribution of life he discovered. But even today we ask ourselves how species formed within the region and why they are not evenly distributed. Biogeography, phylogeny, dispersal, biotic interactions, and abiotic factors affect the assembly of diversity. On the basis of a decade of research on the ecology, evolution, and systematics of corvoid passerine birds, we summarize what we have learned about the biogeography and assembly of island bird diversity. Corvoid passerine birds include nearly 800 species and 2,300 named taxa and thus represent a large, well-described, and globally distributed clade. Understanding the processes influencing biodiversity in this group is certain to deepen our general understanding of ecology and evolution in the context of biogeography and faunal assembly. 231

Phylogeography of a ‘great speciator’ (Aves:Edolisoma tenuirostre) reveals complex dispersal and diversification dynamics across the Indo‐Pacific

“…Such evolutionary cycles of shifting range and dispersal ability have been inferred in various island taxa (e.g. Jønsson et al., , ; Ricklefs & Cox, ; Wilson, ). Here, we draw on patterns of elevational distribution, dispersal ability and species age of Edolisoma taxa to discuss the diversification dynamics of this radiation in the context of taxon cycles.…”

“…Such evolutionary cycles of shifting range and dispersal ability have been inferred in various island taxa (e.g. Jønsson et al, 2014Jønsson et al, , 2017Ricklefs & Cox, 1972;Wilson, 1961).…”

“…Based on well-supported phylogenetic relationships from the BEAST analyses, the geographic affinities of these relationships and the structure of the haplotype network, we defined nine major putative phylogeographic populations within the complex (Figure 1). Uncorrected pairwise p-distances based on the ND2 gene were calculated using MEGA 6 (Tamura, Stecher, Peterson, Filipski, & Kumar, 2013), and we used a Mantel test to test for a correlation between genetic distance and geographic distance between sample locations (using IBDWS 3.23, Jensen, Bohonak, & Kelley, 2005) within the E. tenuirostre complex. We removed eight samples found within the species' non-sedentary range (Eastern Australia, Taylor, 2005) to remove confounding effects of seasonally migrating individuals.…”

Reconciling supertramps, great speciators and relict species with the taxon cycle stages of a large island radiation (Aves: Campephagidae)

“…Although this suggests direct competition between species, young sympatric species pairs occurred within 1.6 Myr in each genus indicating rapid stages of differentiation and colonization (Weir & Price, ). Competition with species outside of the Campephagidae, in particular with other members of the Corvides (see Jønsson et al., ), might also have affected distributions (as suggested for the African clades) and morphological adaptations.…”

The association between morphological and ecological characters across a global passerine radiation

“…wings, bills, feet, tarsi; Figure ). Second, the Corvides are globally distributed, being found throughout the world's major continental landmasses and many island archipelagos (Jønsson et al, , ; Kennedy et al, ). Third, species of the Corvides together encompass the vast majority of passerine morphological space (Jønsson et al, ; Kennedy et al, ), with their extensive morphological and behavioural variation commonly inferred to correspond with extensive ecological diversity.…”