The formation of the Indo-Pacific montane avifauna

• Published in: Nature communications Vol. 14; no. 1; p. 8215
• Main Authors: Reeve, Andrew Hart, Kennedy, Jonathan David, Pujolar, José Martín, Petersen, Bent, Blom, Mozes P. K., Alström, Per, Haryoko, Tri, Ericson, Per G. P., Irestedt, Martin, Nylander, Johan A. A., Jønsson, Knud Andreas
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 11-12-2023; Nature Publishing Group; Nature Portfolio
• Subjects: 45; 45/22; 45/23; 631/158/670; 631/158/852; 631/181/457; 631/181/759; Archipelagoes; Avifauna; Biodiversity; Brittleness; Colonization; Ecosystems and species history; Ekosystem och arthistoria; Humanities and Social Sciences; Hypotheses; Lowlands; Mountains; multidisciplinary; Phylogeny; Population studies; Populations; Science; Science (multidisciplinary); Species
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-43964-y

The processes generating the earth’s montane biodiversity remain a matter of debate. Two contrasting hypotheses have been advanced to explain how montane populations form: via direct colonization from other mountains, or, alternatively, via upslope range shifts from adjacent lowland areas. We seek to reconcile these apparently conflicting hypotheses by asking whether a species’ ancestral geographic origin determines its mode of mountain colonization. Island-dwelling passerine birds at the faunal crossroads between Eurasia and Australo-Papua provide an ideal study system. We recover the phylogenetic relationships of the region’s montane species and reconstruct their ancestral geographic ranges, elevational ranges, and migratory behavior. We also perform genomic population studies of three super-dispersive montane species/clades with broad island distributions. Eurasian-origin species populated archipelagos via direct colonization between mountains. This mode of colonization appears related to ancestral adaptations to cold and seasonal climates, specifically short-distance migration. Australo-Papuan-origin mountain populations, by contrast, evolved from lowland ancestors, and highland distribution mostly precludes their further colonization of island mountains. Our study explains much of the distributional variation within a complex biological system, and provides a synthesis of two seemingly discordant hypotheses for montane community formation.
The mechanisms generating montane biodiversity remain incompletely understood. Here, the authors study the passerine avifauna of Indo-Pacific island mountains, finding that Eurasian-origin species colonized directly from other mountains, while Australo-Papuan-origin species made upslope range shifts from the lowlands.