Dendrochronology in Southeast Asia

Dendrochronological research in Southeast Asia is under development; however, the amount of tress with potential for dendrochronological studies is restricted. For example, teak trees from India, Myanmar, Thailand, and Java are valuable dendrochronologic studies for ready climate response. Teak from Java is best suited for studying the El Niño-Southern Oscillation and sea-surface temperatures, whereas Indian teak is used to reconstruct periods of drought in India. Further, Thai teak and Vietnamese cypress trees captured the long drought period that led to the demise of the Angkor reign (fourteenth–fifteenth century). Diverse techniques including anatomical observation, cambial markings, cell differentiation, and isotopic analysis prove the age and growth of invisible tropical tree rings. A number of invisible growth rings in trees from both tropical and subtropical forests have been identified, resulting in the advancement of dendrochronology. Climate change is a substantial challenge for most living things and natural resources. A greater understanding of tree species adaptation in this region is necessary. The understanding of long-term paleoclimate can be gained by researching old samples and archaeological materials from this region.     

Microbial control in Southeast Asia

Beginning in the 1980s, concerns about the deleterious effects of synthetic pesticides have driven a significant Southeast Asian research and development effort directed towards alternative pest control strategies, including the use of microbial control agents. Despite this effort, use of microbial control agents has grown slowly in the region. This is the result of an interplay between internal factors such as economics, national research programs, farmer education, manufacturing capabilities and regulatory frameworks, and external factors such as the influence of neighboring countries (particularly China), the availability of competitive pest control products, import regulations on pesticide residues and the activities of donor agencies. The role of these factors in providing both incentives and barriers to the adoption of microbial control are explored, and examples of promising projects are examined as a means of pointing the way forward towards increased progress in the future.     

Surface area of woody organs of an evergreen broadleaf forest tree in Japan and Southeast Asia

Architecture of evergreen broadleaf trees in evergreen warm-temperate and tropical forests was analyzed with a ratio (U/Ac) of total surface area of aboveground woody organs to leaf area (one-sided surface area) of each felled tree. The ratio,U/Ac, tended to decrease with the increasing ofdbh. There was little difference in a range of the ratio at eachdbh class between a warmtemperate forest and a tropical rainforest. The ratios of larger trees correlated with their relative growth rates ofdbh among similar sized trees. Canopy trees tended to stop their growth at some value of a ratio, a threshold value being about 1.5, irrespective of forest types. The threshold value showed the critical condition that annual respiration of woody organs of a tree consumed nearly all surplus production. On the basis of the pipe model, an ideal maximum tree height was considered with the ratio, and was estimated at 110 m and 70 m in a tropical rainforest and a warm-temperate forest, respectively.     

Development of microsatellite markers for Dryobalanops aromatica (Dipterocarpaceae), a tropical emergent tree in Southeast Asia

Eight polymorphic microsatellite markers were developed in Dryobalanops aromatica, an emergent tree in tropical rain forests in Southeast Asia, using an enriched library method. For the assessment of microsatellite variation, 36 individuals from a natural population were analysed. The number of alleles per locus ranged from three to 16, with observed heterozygosity of 0.056–0.833 and expected heterozygosity of 0.054–0.882. These microsatellite markers will be useful for studies of population genetics, reproductive ecology and regeneration dynamics of D. aromatica.     

Biodiversity inventory and informatics in Southeast Asia

Rapidly changing land use in Southeast Asia threatens plant diversity, and reduces the time we have left to document it. Despite over 200 years of scientific plant exploration, many plant species have yet to be discovered. Moreover, we still have a very poor understanding of the distribution of known taxa in this biogeographically complex region. We review the current state of biodiversity exploration, using plants in Indonesia as an example. Traditional methods of collecting and describing species have provided a solid foundation for our understanding of plant biodiversity, but are insufficient for the pragmatic task of rapidly discovering and documenting today’s biodiversity before it is gone, because general collecting expeditions tend to be infrequent, and documentation of most new species must await taxonomic revisions many years in the future. Solutions to this exploration and documentation crisis (i) could use the abundant resource of enthusiastic, networked, national biology students, (ii) should employ biodiversity informatics tools to efficiently engage both specialists and parataxonomists, and (iii) might require adoption of new types of α-taxonomy, utilizing increasingly low-cost molecular methods and high resolution photographs. We describe emerging technologies that will facilitate this taxonomic development. We believe that a new golden age of biodiversity exploration may be dawning, just as biodiversity itself is most threatened, and are hopeful that increasing knowledge of biodiversity will be a positive force to slow its loss.     

Low genetic variation detected within the widespread mangrove species Nypa fruticans (Palmae) from Southeast Asia

Genetic diversity within and among six natural populations of Nypa fruticans from China, Vietnam, and Thailand was assessed using SSR and ISSR analysis. Our results showed an extremely low level of genetic diversity of N. fruticans (at the species level, P = 11.76% and 2.88%, He = 0.0279 and 0.0113, I = 0.0470 and 0.0167 by SSRs and ISSRs, respectively) across a total of 183 individuals. No genetic variation was detected within any population except for the Thailand population by SSRs (P = 11.76%, He = 0.0417; I = 0.0622). The bottlenecks during glacial epochs, founder effects, and propagation pattern may be responsible for the extremely low level of genetic diversity of N. fruticans.     

Characteristics of Pleistocene megafauna extinctions in Southeast Asia

The extinction of large-bodied taxa from the Pleistocene in Southeast Asia is examined. Although the chronological resolution of these extinctions is poor, and number of excavations in the region relatively few, broad characteristics of these extinctions can be described. Many taxa which became extinct appear to have been endemic to regions within Southeast Asia, while some taxa which experienced extinction or severe range reduction occurred in several regions. Members of the latter group include proboscideans (Stegodon and Palaeloxodon), the pygmy hippopotamus (Hexaprotodon), the orangutan (Pongo), hyenas (Crocuta and Hyaena), the giant panda (Ailuropoda), tapirs (Tapirus and Megatapirus), rhinoceroses (Rhinoceros), and the giant Asian ape Gigantopithecus. The loss of these species cannot be assigned to a single cause. Rather their disappearance is likely tied to both climatic and human agents. Unlike other regions which experienced megafauna extinctions, eustatic changes in sea level in Southeast Asia seems to have been an important factor.     

Biogeography of polypores in Malesia,Southeast Asia

Biogeography of polypores distributed in the Malesian region is reviewed. Some of the species reported from this region are pantropical or paleotropical and widely distributed along the equator. Several species are restricted to lowland areas of Malesia and adjacent regions, and can be classified as Asian or Asian-Oceanian tropical species. Some species have only been recorded from lowland areas of Malesia at present, but detailed distributions are unclear for many of them. Some lowland Malesian species are also distributed in temperate areas of East Asia; among them, few species are circumglobal in the Northern Hemisphere, whereas many others are tropical species showing continuous distributions up to the warm temperate areas of East Asia. Species recorded from highland areas of Malesia include tropical species common to lowland Malesia, temperate species common to temperate Asia, and endemic species in highland areas of Malesia and adjacent regions. Regarding the factors that delimitate distribution of the Malesian polypores, I discuss polypore host preference, response to physical environmental factors, and dispersal ability. Systematics and ecological characteristics are briefly discussed for selected Malesian polypores: Corneroporus subcitrinus, Paratrichaptum accuratum, Postia stellifera and Roseofavolus eos.     

Options to Combat Maritime Piracy in Southeast Asia

Modern maritime piracy has become one of the major threats to safety at sea. How to combat maritime piracy in Southeast Asia effectively is the major concern of this contribution. It is argued that some form of government cooperation involving most of the governments of the Southeast Asian region is the best way to combat maritime piracy, although it is not an easy task due to various political, economical, and historical reasons. A unilateral and expedient arrangement by one or a few governments to combat maritime piracy may be convenient but may also encounter resistance or raise suspicion from other governments.