DNA Barcodes Confirm the Taxonomic and Conservation Status of a Species of Tree on the Brink of Extinction in the Pacific

Abstract

The taxonomic status of a single island, narrow range endemic plant species from Palau, Micronesia (Timonius salsedoi) was assessed using DNA barcode markers, additional plastid loci, and morphology in order to verify its conservation status. DNA barcode loci distinguished T. salsedoi from all other Timonius species sampled from Palau, and were supported by sequence data from the atpB-rbcL intergenic spacer region. Timonius salsedoi was only known from two mature individual trees in 2012. Due to its extremely narrow range and population size, it had previously been recommended to be listed as Critically Endangered Status under three separate IUCN Criteria. In 2014 a second survey of the population following a typhoon revealed that the only two known trees had died suggesting that this species may now be extinct. Comprehensive follow up surveys of suitable habitat for this species are urgently required.

Plant DNA barcodes: Applications today and in the future

“…Even though the earth may be undergoing its sixth major extinction with extinction rates over 1000 times normal (Wilson, ), observing a species extinction event is rare. Plant DNA barcodes were used to verify that a narrow range endemic tree in the family Rubiaceae, known only from two mature individuals on the island of Palau in Micronesia, was most likely a distinct species in the genus Timonius (Costion et al, ). Additional morphological and molecular data verified that this taxon was T. salsedoi Fosberg & Sachet described in the 1980s.…”

“…In 2014 after a survey of the island where these two individuals were known to occur it was discovered that both trees had succumbed when a typhoon hit the area. Previously recommended as Critically Endangered by IUCN criteria, it is now suspected that this species is extinct (Costion et al, ).…”

The Expanding Role of DNA Barcodes: Indispensable Tools for Ecology, Evolution, and Conservation

“…For plants the extinction of only 571 species over the last several hundred years has been carefully documented [180]. On the island of Palau in Micronesia, plant DNA barcodes were used to verify that a narrow range endemic tree described in the 1980s known from only two mature individuals was Timonius salsedoi Fosberg and Sachet in the family Rubiaceae [181]. Subsequently, after a typhoon hit the area, a survey of the island revealed that both trees had perished.…”

A Concise Review of Dendrocalamus asper and Related Bamboos: Germplasm Conservation, Propagation and Molecular Biology

“…Thereafter, trnH-psbA and ITS (or ITS2) were suggested as complementary markers to the core barcode of rbcL + matK [259]. Later, some studies concentrated on evaluating the identification capability of specific groups using these four barcode loci [260][261][262][263][264], and others have focused on the discovery of new markers suitable for a given taxa [265][266][267].…”