Phylogenetic Relationship of Physocarpus insularis (Rosaceae) Endemic on Ulleung Island: Implications for Conservation Biology

Abstract

Ulleung Island is a biodiversity hot spot harboring approximately 700 species of vascular plants with high number of endemic taxa. Physocarpus insularis, one of the 41 endemic species, has an extremely restricted distribution range on the very small, geologically young oceanic island. Phylogenetic relationship of P. insularis, however, remained highly controversial whether it is conspecific with Spiraea chamaedryfolia or a distinct species in Physocarpus, making it difficult to establish necessary conservation programs. We examined comparative morphology of Physocarpus and Spiraea and reconstructed the phylogeny of the rbcL, matK, ndhF, and trnL-trnF regions from the exemplars of Rosaceae. The results strongly supported the placement of P. insularis within Spiraea. Further phylogenetic analyses of tribe Spiraeeae based on the trnL-trnF and internal transcribed spacer data showed that P. insularis is closely related to S. chamaedryfolia. Morphological analysis revealed that P. insularis differs from S. chamaedryfolia by having larger leaf blades that are subcordate or truncate at base. Results of this study suggest that P. insularis should be recognized as a distinct taxon in Spiraea and that conservation efforts on Ulleung Island should focus on protecting its natural environment to conserve evolutionary patterns and processes in addition to specific conservation programs for species in peril.

Anagenetic speciation in Ullung Island, Korea: genetic diversity and structure in the island endemic species, Acer takesimense (Sapindaceae)

“…One of the important characteristics of the endemics is that most of them are single representatives of different genera that appear to have diverged via simple anagenetic change from continental progenitors (Sun and Stuessy 1998). The relationships between progenitors in continental areas and endemic species in Ullung Island have been confirmed in several genera by phylogenetic studies (Oh et al 2010; Pfosser et al 2002, 2005, 2011; Yang and Pak 2006; Yang et al 2012), indicating that most of the progenitor species are distributed in the Korean peninsula and/or Japanese Archipelago.…”

Phylogenetic Relationships in the Genus <i>Spiraea</i> (Rosaceae) Inferred from the Chloroplast DNA Region, <i>trn</i>L-<i>trn</i>F

“…It is a general principle that the higher the genetic divergence among phylogenetic lines, the earlier the many taxa diverged. This has been widely applied in the interpretation of biogeographical history using sequence data [19]. A possible explanation might be that different areas with different environments will vary in mutation accumulation or divergence maintenance and consequently differ in detectable evolutionary rate.…”

Analysis of the Phylogenetic Relationships in the Genus Spiraea Based on the Nuclear Ribosomal DNA ITS Region

“…Morphologically, the complex is very diverse with diagnostic characters separating varieties combined in different ways within it, resulting in taxonomic confusion and difficulty in determining boundaries of varieties [8,19]. Taxonomic problems are further compounded because some varieties, especially taxa in Korea, are geographically sympatric and appear to hybridize readily [9].…”