Phytochemical and pharmacological properties of the genus Pseudotsuga.

Why red‐dominated autumn leaves in America and yellow‐dominated autumn leaves in Northern Europe?

<p>Interannual variation of tropical cyclone (TC) landfall frequency is not consistent along the coast of East Asia, with large contrast of north and south East Asia coast regions in boreal summer. This study examines interannual variations of TC landfall frequency over north and south East Asia and identifies roles of the western North Pacific subtropical high (WNPSH) and TC genesis frequency associated with these variations. Although the total number of landing TC of north and south East Asia is similar, interannual variations of TC landfall frequency are relatively independent to each other, with the corresponding correlation coefficient north and south of 25°N is only –0.024 from 1979 to 2017. TC landfall over north East Asia is largely modulated by the circulation related to the WNPSH, while TC landfall in the south has no significant relationship with the WNPSH or other remote large-scale circulations. The WNPSH effectively regulates TC landfall in the north by modulating TC genesis east of the Philippines and steering flows. Nonetheless, the two factors have weak contradictory effects on TC landing in the south region. The frequency of TC genesis around the South China Sea directly connects to the TC landfall over south East Asia, which is modulated by the surrounding genesis environment, including relative humidity and relative vorticity. This work favors for a better understanding of the seasonal forecasts of TC landfall frequency and the subsequent climate service over East Asia.</p>

Much information on distribution and taxonomy of North American trees with relationships in eastern Asia, including atlases and monographs, is now available.Eastern Asia is the world's largest and richest source of temperate deciduous hardwoods.Because of splitting of genera and species, relationships are becoming obscured and are primarily generic.Eastern Asia is the geographic region

Similarities in the temperate floras of eastern Asia and North America have been appreciated for more than 200 yr, but the generality of the floristic relationships among eastern Asia (EAS), eastern North America (ENA), and western North America (WNA), postulated by Asa Gray about 150 yr ago, has not been tested until now. In this article, floristic relationships based on genera shared among EAS, ENA, and WNA were examined at different spatial scales for different phylogenetic groups using complete floras. Floristic similarity between EAS and ENA is higher than that between EAS and WNA, and the floras of ENA and WNA are more closely related to each other than are the floras of EAS and ENA. Compared with ENA and WNA, the number of genera common to EAS and ENA is significantly higher in basal angiosperms and significantly lower in asterids. Floristic similarities tend to decrease from more basal to more modern lineages between EAS and ENA and between EAS and WNA but not between ENA and WNA. Similarly, from more basal to more modern divisions, the fraction of shared genera decreases between EAS and ENA and between EAS and WNA, whereas the floristic similarity between ENA and WNA tends to increase. Furthermore, floristic similarity between EAS and ENA increases with latitude. The causes of the observed patterns of floristic similarity between EAS, ENA, and WNA are discussed.

Carex sect. Paniceae sensu lato (s.l.) exhibits two major disjunct centers of diversity: eastern North America and East Asia. This pattern, commonly observed in other plant groups, has been associated with trans‐Pacific dispersal from Asia to America and subsequent local extinctions in western North America. This study reconstructed a phylogenetic tree using two nuclear (external transcribed spacer and internal transcribed spacer) and three plastid (matK, trnL‐F, and rpl32‐trnLUAG) regions, along with 474 nuclear loci from high‐throughput sequencing (Hyb‐Seq). Dating analysis and ancestral area reconstruction were used to investigate the evolutionary and biogeographic history of sect. Paniceae s.l. A broader circumscription of sect. Paniceae s.l., incorporating sects. Bicolores and Laxiflorae, is established. Two primary clades were identified: one clade predominantly diversified in North America and the other in East Asia. Biogeographic analyses suggested a likely origin of sect. Paniceae s.l. in the Palearctic during the Late Miocene. The most probable scenario involved dispersal to eastern North America via the Western Palearctic, followed by subsequent dispersal into western North America, other parts of the continent, and back to the Old World. Within East Asia, the group was inferred to have diversified during the Pliocene and Pleistocene, with the basalmost nodes inferred in mainland China. Multiple dispersal events from this region to the Russian Far East, Korea, and Japan were inferred. This study highlights the underexplored role of East Asia in the biogeography of grass‐like plants and the existence of alternative migration routes in explaining the East Asia–eastern North America pattern of disjunction.

Hong De-Yuan, The Distribution of Scrophulariaceae in the Holarctic With Special Reference to the Floristic Relationships Between Eastern Asia and Eastern North America, Annals of the Missouri Botanical Garden, Vol. 70, No. 4 (1983), pp. 701-712

During the 1970s, there was a great deal of interest in the discourse on the law of the sea and ocean policy. However, since the adoption of the United Nations Convention on the Law of the Sea (UNCLOS) in 1982 that discourse has been on the wane. Ratification of the Convention by the United States can increase the chances of the Convention enjoying universal acceptance. The Convention serves as the basis for settlement of competing claims, mostly unilateral claims made by states on the uses and resources of the ocean. One positive development in recent years is the global trend toward international adjudication. However, solving disputes through adjudication is not yet part of the legal culture of East Asian countries. In view of the increasing tension in the East Asia region, both in the Northeast and Southeast Asian seas, all states concerned need to return to the path of dialogue. Keywords:international adjudication; North East Asia; South East Asia; UNCLOS

Understanding and forecasting species’ response to climate change is a critical need for future conservation and management. Two expansion hypotheses, the glacial expansion versus the interglacial expansion, have been proposed to interpret how cold-adapted organisms in the northern hemisphere respond to Quaternary climatic fluctuations. To test these two hypotheses, we originally used two pairs of high-low elevation firs from North America (Abies lasiocarpa and Abies balsamea) and East Asia (Abies chensiensis and Abies nephrolepis). Abies lasiocarpa and Abies chensiensis are widely distributed in high-elevation regions of western North America and central China. Abies balsamea and Abies nephrolepis occur in central North America and northeast China, with much lower elevations. These fir species are typical cold-adapted species and sensitive to climate fluctuations. Here, we integrated the mtDNA and cpDNA polymorphisms involving 44 populations and 585 individuals. Based on phylogeographic analyses, recent historical range expansions were indicated in two high-elevation firs (Abies lasiocarpa and Abies chensiensis) during the last glaciation (43.8–28.4 or 21.9–14.2 kya, 53.1–34.5 or 26.6–17.2 kya). Such glacial expansions in high-elevation firs were further confirmed by the evidence of species distribution modelling, geographic-driven genetic patterns, palynological records, and current distribution patterns. Unlike the north American firs, the SDM models indicated unremarkable expansion or contraction in East Asia firs for its much more stable conditions during different historical periods. Taken together, our findings highly supported that high-elevation firs experienced glacial expansion during the Quaternary climate change in East Asia and North America, as interglacial expansion within low-elevation firs. Under this situation, the critically endangered fir species distributed in high elevation would have no enough higher elevational space to migrate. Facing the increasing global warming, thus we proposed ex-situ conservation of defining conservation units as the most meaningful strategy.

The hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), is an introduced pest of unknown origin that is causing severe mortality to hemlocks (Tsuga spp.) in eastern North America. Adelgids also occur on other Tsuga species in western North America and East Asia, but these trees are not significantly damaged. The purpose of this study is to use molecular methods to clarify the relationship among hemlock adelgids worldwide and thereby determine the geographic origin of the introduction to eastern North America. Adelgids were collected from multiple locations in eastern and western North America, mainland China, Taiwan, and Japan, and 1521 bp of mitochondrial DNA was sequenced for each sample. Phylogenetic analyses suggest that the source of A. tsugae in eastern North America was likely a population of adelgids in southern Japan. A single haplotype was shared among all samples collected in eastern North America and samples collected in the natural range of T. sieboldii in southern Honshu, Japan. A separate adelgid mitochondrial lineage was found at higher elevations in the natural range of T. diversifolia. Adelgids from mainland China and Taiwan represent a lineage that is clearly diverged from insects in North America and Japan. In contrast to eastern North America, there is no conclusive evidence for a recent introduction of A. tsugae into western North America, where multiple haplotypes are found. Implications for hemlock woolly adelgid control, taxonomy, and plant–insect coevolution are discussed.

A new species of Pseudotsuga (Pinaceae) from the lower Miocene of Lesvos, Greece, and its palaeogeographical and palaeoclimatic implications

The nuclear ribosomal DNA (nrDNA) internal transcribed spacer (ITS) region has been characterized in the sister genera Larix and Pseudotsuga (Pinaceae). Complete sequences were obtained for seven species of Larix from North America and Eurasia and five species of Pseudotsuga from western North America and eastern Asia. ITS region lengths ranged from 1759 to 1770 bp in Larix and from 1564 to 1571 bp in Pseudotsuga. In both genera, ITS1 is three times as long as the 5.8S plus ITS2 and contains subrepeats as observed in other genera of Pinaceae. Secondary structure models predicted that the subrepeats fold into terminal stem and loop domains. ITS polymorphism detected within individuals of Larix and Pseudotsuga suggests a slow rate of concerted evolution among nrDNA loci. Except for the placement of L. sibirica, phylogenetic analyses of the ITS region agreed with previously reported restriction site analyses of Larix and Pseudotsuga. The data were not consistent with phylogenetic hypotheses for Larix based primarily upon ovulate cone characters, failing to support a derivation of the North American L. laricina from a short-bracted Eurasian lineage. The phylogenetic hypothesis did not conflict with a stepping stone model of evolution for Pseudotsuga, but a basal lineage could not be inferred for either genus.

T Z a HE WORLD iS considered as having three major regions: Western Europe, North America and East Asia. Unlike the other two regions, however, East Asia is not as well defined as an economic region. While Western Europe and North America are economically institutionalized by the European Union (EU) and the North American Free Trade Agreement (NAFTA) respectively, East Asia has no comparable regional arrangement. This paper argues that East Asia is a globally defined economic region different from the other major regions. While cultural and economic diversity prevents formal integration, regional integration has been achieved by informal means such as regional production networks, ethnic business networks and subregional economic zones. The case of economic integration in East Asia also adds to conventional theories of economic integration by providing an alternative to the EU-type formal integration. This paper studies the regional production network (RPN), a major regional element of Asian economic integration. These networks, driven by the foreign direct investment (FDI) from Japan and based on a multi-tier division of labor, are stitching together the disparate economies of Asia, integrating them with one another.' They helped to launch first the East Asian newly industrialized economies (EANIEs) and then those of the ASEAN Four (Thailand, Malaysia, Indonesia and the Philippines) and China. The RPN has created a trade triangle amongJapan, East Asia and North America (In this paper, East Asia is referred as Northeast Asia and Southeast Asia, but when it is used in parallel to Japan, Japan is not included.). In this triangle, Japan provides capital goods and technology to East Asia, East Asia exports consumer goods to North America, and North America is a major market for both Japan and East Asia. However, while the RPN was the dominant form of informal integration in the past, its weakness has also recently become

Species are distributed heterogeneously, and different regions have contrasting numbers of species, producing species richness anomalies. More than 100 angiosperm genera demonstrate disjunct distributions in at least two of these regions: Europe, eastern North America, western North America, and East Asia, and commonly between East Asia and eastern North America. These regions have similar climates but usually exhibit species richness anomalies; however, the underlying causes of species richness anomalies in disjunct intercontinental regions remain poorly understood. In this study, we investigated the drivers of anomalies in ash tree (genus Fraxinus L.) species richness anomalies among disjunct intercontinental regions based on distribution data, macrofossil records, and corresponding evolutionary and environmental variables. Generalized linear regression and pathway model analyses incorporating environmental and evolutionary processes indicated that global cooling has contributed to low species richness in Europe, whereas evolutionary divergence, shaped the distinct species distribution patterns in East Asia (which was identified as an evolutionary cradle) and North America (which was identified as an evolutionary museum). Environmental heterogenies and evolutionary divergence have resulted in a significant diversity anomaly between these regions. This study emphasizes the important role of evolution in the formation of species richness distribution patterns.

The origin and evolution of tertiary relict floras

The Younger Dryas (YD) climate event is the preeminent example of abrupt climate change in the recent geologic past. Climate conditions during the YD were spatially complex, and high-resolution sediment cores in the North Atlantic, western Europe, and East Asia have revealed it unfolded in two distinct stages, including an initial stable climatic period between ~ 12.9 and 12.2 ka associated with a weakened Atlantic Meridional Overturning Circulation (AMOC) and a second phase characterized by variable conditions until 11.7 ka as the AMOC recovered. Decades of investigations into the climate of western North America during the YD have failed to identify this stepped phenomenon. Here we present hydroclimate data from paleospring deposits in Death Valley National Park (California, USA) that demonstrate unequivocal evidence of two-stage partitioning within the YD event. High groundwater levels supported persistent and long-lived spring ecosystems between ~ 13.0 and 12.2 ka, which were immediately replaced by alternating wet and dry environments until ~ 11.8 ka. These results establish the mid-YD climate transition extended into western North America at approximately the same time it was recorded by hydrologic systems elsewhere in the Northern Hemisphere and show that even short-lived changes in the AMOC can have profound consequences for ecosystems worldwide.