Ancestral range reconstruction of remote oceanic island species of Plantago (Plantaginaceae) reveals differing scales and modes of dispersal

Abstract

Aim The aim of this study was to resolve the phylogenetic placement of island taxa, reconstruct ancestral origins and resolve competing hypotheses of dispersal patterns and biogeographical histories for oceanic island endemic taxa within subgenus Plantago (Plantaginaceae). Location Juan Fernández Islands, the Auckland Islands, Lord Howe Island, New Amsterdam Island, New Zealand, Tasmania, Falkland Islands, Rapa Iti and the Hawaiian Islands. Taxon Island endemics within Plantago (Plantaginaceae), a globally distributed taxonomic group comprising approximately 250 species. Methods We use Bayesian phylogenetic and divergence time analyses and historical biogeographical analysis of molecular sequence data to infer the ancestral origins of the oceanic island species in Plantago . Results Taxa within subgenus Plantago form clades based on geographic proximities and challenge previous phylogenetic relationships and classification based on morphology. We infer that biogeographic histories of oceanic island taxa from multiple islands were shaped by dispersal at different scales and possibly by different types of birds. The highly remote Hawaiian Islands and Rapa Iti were colonized from North American taxa in a pattern corresponding to known migration routes of large marine birds, rather than from New Zealand as previously hypothesized. The island endemics of Juan Fernández, the Falkland Islands, Lord Howe, Auckland Islands and New Zealand are found to have sources in the nearest continental areas. The analyses confirm recent speciation within subgenus Plantago – which is particularly heightened in island lineages in Hawaii and Rapa Iti – but show slightly older divergence times than previous molecular dating studies. Main conclusions Using molecular data to infer ancestral ranges for plants with uncertain taxonomic relationships can greatly improve our understanding of biogeographical histories and help elucidate origins, dispersal modes and routes in widespread lineages with complex distribution patterns such as Plantago . We improve understanding of important floristic exchange areas between continents and islands as a result of long‐distance dispersal. We infer that a combination of both stepping stone dispersal and extreme long‐distance dispersal can shape insular floras, and that multiple floristic areas can be the sources of closely related island taxa. However, despite the successful dispersal of Plantago , radiation in island archipelagos is generally limited suggesting specific traits may limit diversification.

Expanded inverted repeat region with large scale inversion in the first complete plastid genome sequence of Plantago ovata

“…S6). Similar results were reported by Iwanycki Ahlstrand et al 45 on the basis of various genes that subgenus Plantago diverged about 8.8 Mya (95% HPD, 17.4-2.5 Mya). These results are also consistent with the divergence time estimation of family Plantaginaceae where its crown age was estimated 31.42 Mya 46 .…”

How to map a plantain: phylogeny of the diverse Plantagineae (Lamiales)

“…Carpophorae species are sister to P. fernandezia + P. barbata. This group likely has an Andean origin, and P. fernandezia might, therefore, arrive at Juan Fernández from South America (Stuessy et al, 2017;Iwanycki Ahlstrand et al, 2019). Position of P. fernandezia, P. tehuelcha, and sect.…”

“…This situation has shown signs of improvement lately, and several publications which cover the complicated Plantago subg. Plantago (e.g., Hassemer et al, 2019;Iwanycki Ahlstrand et al, 2019) and subg. Coronopus (Höpke et al, 2019;Hassemer et al, 2017;Hassemer 2018b) are now available.…”

Travel tales of a worldwide weed: genomic signatures reveal colonial trade routes and prior adaptation are key to the success of Plantago major

“…Plantago major has been extensively studied in its native range and a wealth of ecological, physiological and genetic information is available for the species (Mølgaard, 1976;Kuiper & Bos, 1992;Morgan-Richards & Wolff, 1999). It possesses many of the traits that are common amongst the most successful introduced plants (Pysek et al, 2009;Hejda et al, 2014;Pysek et al, 2015), including high phenotypic plasticity, large ecological amplitudes, a high tolerance to human disturbance, rapid growth rates, and the production of propagules with specialized adaptations for long-distance dispersal such as mucilaginous seeds and wind pollination (Young & Evans, 1973;Hawthorn, 1974;van Dijk, 1984;Rahn, 1996;Samuelsen, 2000;Kreitschitz, Kovalev, & Gorb, 2016;Iwanycki Ahlstrand et al, 2018;Iwanycki Ahlstrand et al, 2019). Furthermore, the species is capable of self-fertilizing, meaning that a single propagule can putatively establish sexually reproducing populations in new ranges (Baker, 1974;Wolff, 1991).…”

“…Plants could have been introduced to southern Africa and then further dispersed to Australia. Alternatively, plants could have arrived with the Portuguese to Timor in the 16 th century (Mancall, 2006), approximately 650 km from the Australian coast, and later dispersed by birds to Australia (Iwanycki Ahlstrand et al, 2019). The first record for the species in Australia is in 1770 (GBIF.org), around the same period the English made their first voyages there, which indicates that plant may have arrived with earlier explorers such as the Dutch, who arrived in Australia (and New Zealand) in the 17 th century (Mancall, 2006).…”