Yukito Nakamura

A phytosociological survey of the deciduous temperate forests of mainland Northeast Asia

This study represents the first survey of the temperate deciduous forests of mainland Northeast Asia on the territories of the Russian Far East, northeast China and Korea. A total of 1200 relevés are used, representing nemoral broadleaved (Fraxinus mandshurica, Kalopanax septemlobus, Quercus mongolica, Tilia amurensis)-coniferous (Abies holophylla, Pinus koraiensis) forests, and broadleaved Quercus spp. forests. The vegetation is classified into 4 orders, 12 alliances, 50 associations, 36 subassociations and 8 variants. One order, Lespedezo bicoloris-Quercetal ia mongolicae, 4 alliances Rhododendro daurici-Pinion koraiensis , Phrymo asiat icae-Pinion koraiensis , Corylo heterophyllae-Quercion mongolicae and Dictamno dasycarpi-Quercion mongolicae, and 14 associations are described for the first time. The communities are placed into two classes. Quercetea mongolicae reflects monsoon humid maritime climate with the amount of summer precipitation higher than winter precipitation and the lack of a period of moisture deficit. They occur in Korea, montane regions of China east of the Lesser Hingan and the Sikhote-Alin. Querco mongolicae-Betuletea davuricae unites forests in conditions of semiarid subcontinental climate with summer precipitation considerably higher than winter precipitation and with the period of moisture deficit in spring and early summer. They occupy mostly the regions of northeast China and eastern Russia west of the Lesser Hingan and in the low elevation belts of the southern Sikhote-Alin.

Phytosociological study of thePicea jezoensis forests of the far east

Forest communities dominated byPicea jezoensis (Yezo spruce) are described from across their entire distributional range in eastern Asia, including the territories of the Russian Far East and Japan. A total of 476 relevés are used representing the following dominant types of spruce forests: pureP. jezoensis, mixedP. jezoensis andAbies sachalinensis, mixedP. jezoensis andAbies nephrolepis, and purePicea glehnii communities. The vegetation is classified into 11 associations, 2 community types, 6 subassociations, 25 variants and 8 subvariants. Nine associations, including theAsaro heterotropoidis-Abietetum sachalinensis, Weigelo middendorffianae-Piceetum jezoensis, Lysichito-Piceetum glehnii, Swido albae-Piceetum obovatae, Oplopanaco elati-Piceetum jezoensis, Philadelpho tenuifolii-Piceetum jezoensis, Vaccinio-Piceetum jezoensis, Rhododendro aurei-Piceetum jezoensis, andMoneseto uniflorae-Piceetum jezoensis, are described for the first time. The ecology and structure of all communities are described and their syntaxonomy discussed. The communities are placed in three alliances,Piceion jezoensis, Abieti nephrolepidis-Piceion jezoensis andPino pumilae-Piceion jezoensis, all. nov. All of the communities described are considered to belong to the orderAbieti-Piceetalia of the classVaccinio-Piceetea.

Classification of the High-Mountain Coniferous Forests in Taiwan

Vegetation of boreal coniferous forests has been extensively studied in many areas of northern Eurasia and North America, but similar forests in the high mountains of subtropical and tropical eastern Asia have been poorly documented so far. This paper, focusing on such forests, is the first phytosociological study at a national scale in Taiwan. The relevés from the National Vegetation Diversity Inventory and Mapping Project database were used to define vegetation types of the high-mountain coniferous forests and to characterize their distribution in Taiwan. Environmental variables such as aspect, elevation, soil rockiness and slope were related to species composition. Cluster analysis was used to classify vegetation plots and establish groups that were interpreted as nine associations belonging to two alliances. The alliance Juniperion squamatae represents woodlands and forests scattered in the subalpine belt, in which Juniperus squamata dominates the canopy and subalpine meadow species occur in the understorey. The Abieti kawakamii-Tsugion formosanae alliance includes forests dominated by Abies kawakamii and Tsuga chinensis var. formosana with shade-tolerant herb species in the upper montane belt. In addition to regional vegetation description, an identification key for the studied forests was developed based on the classification tree technique.

Phytogeography of higher units of forests and krummholz in North Asia and formation of vegetation complex in the Holocene.

The modern vegetation pattern of Northern Asia has an uninterrupted history of development from Tertiary boreo-nemoral vegetation complex. The most dramatic transformation of this complex took place in the Pleistocene Maximum, when the low temperatures along with severe climatic aridisation caused a qualitative change of the vegetation in the broad areas of mainland Asia and provided an opportunity for migrations of drought- and cold-tolerant species. This paper focuses on the problem of the contributions of major Asian fl oristic centres to the formation of major vegetation types of Northeast Asia in the changing climatic conditions of the Pleistocene and Holocene. The increasing temperature and humidity in the beginning of Holocene caused the formation and expansion of nemoral forests belonging to the order Tilio-Pinetalia koraiensis composed mainly of humidity-dependent Sino-Japanese species, and nemoral Quercus mongolica forests that included drought-tolerant species of Central Asian origin. In the boreal zone, the larch forests reached the coast of the Arctic Ocean in a relatively short period between 10000 and 6000 years BP. Perhaps this period is the time of formation of the order Ledo-Laricetalia cajanderi composed of species adapted to extremely cold winters, hot summers and cold soils lying on top of the layer of permafrost. The ultra-continental climate in conditions of relatively high temperatures caused deepening of the active soil horizons and differentiation of the order Lathyro-Laricetalia, characterised by the presence of drought-tolerant species of Central Asian and Sino-Japanese origin. These climatic and edaphic conditions appeared to be unfavorable for mesic species. Therefore, the areas with an ultra-continental climate represent an important biogeographical limit for mesic Beringian and Sino-Japanese species. Increasing oceanicity in the period of 5000 - 3500 years BP caused forest retreat that led to the formation of the youngest zonal order of Northern Asia, the Larici-Betuletalia divaricatae characterised by domination by cold tolerant shrubs from the genera Betula, Alnus and Salix.

Temperate Rainforests of Japan

With a rich human history dating back to a Paleolithic time some 30,000 years ago, Japan is home to an astonishing array of plant communities that range from alpine to subtropical and temperate rainforest (Hamet-Ahti et al. 1974; Box 1995). The Japanese archipelago (~377,853 square kilometers) occupies a fraction (~0.8 percent) of the earth’s terrestrial surface and is roughly one twenty-fifth the size of the United States. It is located in a transitional zone between subtropical and subboreal at 30 to 45°N latitude (see figure 7-1). Japan’s mountainous island chain rises to 3,000 meters elevation, where forest transitions to alpine tundra. The lack of glacial influence has served as refugia for numerous species, including many endemics that required humid places during the Pleistocene glacial period.

Formation of disjunct plant distributions in Northeast Asia: a case study of Betula davurica using a species distribution model

Repeated climate change during glacial and interglacial periods of the Quaternary led to mass migrations that resulted in disjunct distributions for many species. However, few studies have examined the processes that form disjunct distributions in Northeast Asia (NEA). In this study, we examined the disjunct distribution of Betula davurica Pall. in the Japanese archipelago. This species is a dominant canopy tree found in cool-temperate deciduous broad-leaved forests of continental NEA. We hypothesized that Quaternary climate change caused the present disjunct distribution pattern of this species. To test this hypothesis, we adopted a species distribution model and examined a series of potential habitats in the Last Glacial Maximum (LGM), the mid-Holocene, and the present. We generated models in MaxEnt with B. davurica presence as the response variable and six bioclimatic variables as predictor variables. During the LGM, projected potential habitats were distributed around the Korean Peninsula, East China, and the Japanese archipelago, excluding Hokkaido. In the mid-Holocene, habitats retreated both from East China and western Japan, remained unchanged in the Korean Peninsula and central Honshu mountains, and expanded to northern China, the Russian Far East, as well as northern Japan (Hokkaido). Thus, post-LGM global warming led to an expansion of B. davurica distribution to northern parts of continental NEA, along with a retreat in the Japanese archipelago. This shift in populations formed the present disjunct distribution.

Crosscutting Issues and Conservation Strategies

Throughout this book we have made the case that temperate and boreal rainforests are unique ecosystems globally and therefore worthy of stepped-up efforts for their study and conservation. Because entire ecosystems (and not just species) are at the brink of extinction (e.g., European relicts, old-growth coastal redwoods), a comprehensive vision is needed to ensure the persistence of rainforests in a time of unprecedented change brought about by the cumulative effects of climate change and ongoing land use.