Geographical and temporal origins of terrestrial vertebrates endemic to Taiwan

Abstract

AbstractAimPhylogeographical studies of Taiwan have advanced our knowledge of the origins of its fauna, but the discrepancies raise issues related to the interpretation of single‐taxon studies. Here, we provide a synthesis of the biogeographical histories of multiple terrestrial vertebrates endemic to Taiwan and infer the colonization processes within the context of geological and climatic events.LocationTaiwan and neighbouring land masses.TaxonTerrestrial vertebrates.MethodsWe conducted a meta‐analysis of 28 phylogenetic studies of 33 endemic Taiwanese terrestrial vertebrates to summarize the insights into their source regions and divergence times. We used dispersal–extinction–cladogenesis models to reconstruct the ancestral ranges of 54 endemic species based on a recently published time‐calibrated phylogenetic tree. By constructing a frequency histogram that quantified the number and timing of divergence events within 1 Myr bins, we inferred the spatiotemporal colonization patterns of endemic Taiwanese species.ResultsThe results from 28 phylogenetic studies revealed that South China is the main source region of endemic Taiwanese species. However, based on a more comprehensive time tree, the ancestral area reconstruction analyses indicated that endemic species are predominately of Eastern Himalayan origin. Both datasets highlighted a temporal pattern that the majority of colonization events of terrestrial vertebrates endemic to Taiwan occurred from the early Pliocene (c. 5 Ma) onwards, and these events were temporally congruent with the geological estimates of the emergence of Taiwan Island.Main conclusionsTerrestrial vertebrates endemic to Taiwan reached the island over the last 5 Myr from a variety of zoogeographical regions. In contrast to the traditional notion, the Eastern Himalayas is the most important source region of endemic Taiwanese species, followed by South China and Indochina. In addition to the land bridge, transoceanic dispersal provided another potential mode for species to colonize Taiwan.