Flora of herbaceous and arboreous plants in Komaba Campus of the University of Tokyo, Japan

Background

Recent studies revealed that green spaces in urban areas are critical for conservation of native biodiversity and that assessment of the present flora of green spaces in urban areas is critical for protection of the native biodiversity. The Komaba Campus of the University of Tokyo embraces a relevant green area, located in a highly urbanised area in Tokyo Metropolis (35.66 N 139.68 E, Japan). The total area of this Campus is 25.4 ha, from which, 4.5 ha are covered by vegetation. Although intense urbanisation can be observed around the Campus, new insect species had been reported for the Campus area, suggesting that the biodiversity on the Campus still demands some attention. Differently from fauna surveys, no flora survey has been done for more than 30 years on the Campus. In this study, we have extensively surveyed the plants diversity on the Komaba Campus of the University of Tokyo, aiming for an update of the plants list on this green urban area in Tokyo.

New information

The survey covered all herbaceous and arboreous plants growing wild on the Campus. Garden plants were excluded in this survey because these plants were supposed to be cultivated. The final dataset contained, in total, 324 taxa, from which 234 were herbaceous plants and 90 were arboreous plants. The top three taxa are as follows: Poaceae (38 taxa), Asteraceae (34 taxa) and Rosaceae (14 taxa), respectively. This is the first update to the Flora of the Komaba Campus of the University of Tokyo in 30 years and represent an important contribution to conservation of native species in the Tokyo metropolis.

Refugia within refugium of Geranium yesoense (Geraniaceae) in Japan were driven by recolonization into the southern interglacial refugium

Recent studies have found that geographical fragmentation and recurrent colonization result in complex genetic structures in refugial areas. This phenomenon, known as ‘refugia within refugium’, has been identified from many geographical locations. In Japan, the high-elevation mountains of central Honshu provided an interglacial refugium for alpine plants. Here we focused on the Geranium yesoense complex, which exhibits increased morphological variation in the refugial area, to determine whether this variation was shaped by recurrent colonization, range fragmentation or phenotypic changes independent of population history. We analysed single nucleotide polymorphism data and chloroplast genome sequences. Diversification in the G. yesoense species complex occurred in the mid-Pleistocene. The varieties are distinct entities and suggest the presence of a genetic cluster with highly disjunct distributions, occurring both in northern Japan and in southern refugial areas in central Honshu. Demographic analysis suggests that a single ancestral variety (var. nipponicum) evolved in the alpine region of central Honshu, and that subsequent migration from one of the two diverged northern varieties (var. pseudopratense) led to secondary contact with var. nipponicum during the last glacial period. Recolonization into refugial populations in central Honshu and hybridization between diverged populations have resulted in complex genetic structures among refugial populations.

Inventory of the Heteroptera (Insecta: Hemiptera) in Komaba Campus of the University of Tokyo, a highly urbanized area in Japan

Background

The Heteroptera, or true bugs, forms one of the major insect groups with respect to the very diverse habitat preferences, including both aquatic and terrestrial species, as well as a variety of feeding types. The first comprehensive inventory of the Heteroptera at Komaba Campus of the University of Tokyo, or an urban green space in the center of the Tokyo Metropolis, Japan, was conducted.

New information

A total of 115 species in 29 families of the suborder Heteroptera were identified. The area had a high species richness compared with other urbanized and suburbanized localities in Tokyo. The campus is found to show a substantial difference in heteropteran species compositions, despite being close to the other localities surrounded by highly urbanized zones in central Tokyo.