The Role of DNA Barcodes in Understanding and Conservation of Mammal Diversity in Southeast Asia

Background

Southeast Asia is recognized as a region of very high biodiversity, much of which is currently at risk due to habitat loss and other threats. However, many aspects of this diversity, even for relatively well-known groups such as mammals, are poorly known, limiting ability to develop conservation plans. This study examines the value of DNA barcodes, sequences of the mitochondrial COI gene, to enhance understanding of mammalian diversity in the region and hence to aid conservation planning.

Methodology and Principal Findings

DNA barcodes were obtained from nearly 1900 specimens representing 165 recognized species of bats. All morphologically or acoustically distinct species, based on classical taxonomy, could be discriminated with DNA barcodes except four closely allied species pairs. Many currently recognized species contained multiple barcode lineages, often with deep divergence suggesting unrecognized species. In addition, most widespread species showed substantial genetic differentiation across their distributions. Our results suggest that mammal species richness within the region may be underestimated by at least 50%, and there are higher levels of endemism and greater intra-specific population structure than previously recognized.

Conclusions

DNA barcodes can aid conservation and research by assisting field workers in identifying species, by helping taxonomists determine species groups needing more detailed analysis, and by facilitating the recognition of the appropriate units and scales for conservation planning.     

Linking Plant Specialization to Dependence in Interactions for Seed Set in Pollination Networks

Studies on pollination networks have provided valuable information on the number, frequency, distribution and identity of interactions between plants and pollinators. However, little is still known on the functional effect of these interactions on plant reproductive success. Information on the extent to which plants depend on such interactions will help to make more realistic predictions of the potential impacts of disturbances on plant-pollinator networks. Plant functional dependence on pollinators (all interactions pooled) can be estimated by comparing seed set with and without pollinators (i.e. bagging flowers to exclude them). Our main goal in this study was thus to determine whether plant dependence on current insect interactions is related to plant specialization in a pollination network. We studied two networks from different communities, one in a coastal dune and one in a mountain. For ca. 30% of plant species in each community, we obtained the following specialization measures: (i) linkage level (number of interactions), (ii) diversity of interactions, and (iii) closeness centrality (a measure of how much a species is connected to other plants via shared pollinators). Phylogenetically controlled regression analyses revealed that, for the largest and most diverse coastal community, plants highly dependent on pollinators were the most generalists showing the highest number and diversity of interactions as well as occupying central positions in the network. The mountain community, by contrast, did not show such functional relationship, what might be attributable to their lower flower-resource heterogeneity and diversity of interactions. We conclude that plants with a wide array of pollinator interactions tend to be those that are more strongly dependent upon them for seed production and thus might be those more functionally vulnerable to the loss of network interaction, although these outcomes might be context-dependent.     

Eden in the East: The Drowned Continent of Southeast Asia

Eden in the East: The Drowned Continent of Southeast Asia. Stephen Oppenheimer. London: Orion (Weidenfeld and Nicolson), 1998.560 pp.     

Changing Perceptions of Risk: The Development of Agro-Ecosystems in Southeast Asia

New long-term environmental sequences for Southeast Asia provide a basis for reevaluating the development of agroecosystems. Previous models depict agricultural development as a singular, relatively rapid response to various stimuli such as climate change and population growth. In contrast, the Southeast Asian data indicate that the development of tropical agro-ecosystems are the result of stresses separated in time and not part of a unitary developmental process. Two phases are evident: At the end of the Pleistocene, environmental data indicate a significant climatic change that would have affected the distribution of food resources. In some areas, this encouraged food production as previous food resources decreased or disappeared. In the second phase, during the mid- Holocene, increased cultural and social risks led to shifts in strategies that created agro-ecosystems—a more fundamental transformation of landscape ecology. This distinct two-phase pattern suggests groups were responding to very different challenges in each period These findings underscore the need to reexamine agricultural models that conflate separate and distinct processes of cultural change. [Keywords: Southeast Asia, tropical land use, phytoliths, agriculture, Thailand]     

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.     

Combatting Piracy and Armed Robbery Against Ships in Southeast Asia: The Way Forward

According to the Annual Reports of the International Maritime Bureau on Piracy and Armed Robbery Against Ships for calendar years 1998, 1999, and 2000, there has been a dramatic increase in the number of reported incidents of piracy and armed robbery against ships in waters in Southeast Asia, especially in the Malacca Strait and in Indonesian waters. Very few of the incidents in Southeast Asia are "piracy" as defined in international law because they took place in waters under the sovereignty of a coastal state. Nevertheless, many of the incidents posed serious threats to the safety of international maritime navigation. Some were offences under the 1988 Convention for the Suppression of Acts Against the Safety of International Maritime Navigation. Some were also major criminal hijacks involving international organized crime. There has been considerable action at both the global and regional levels to attempt to deal with this threat to the safety of international navigation. This article analyzes the reported incidents and the attempts by the international community to deal with the problem. The article concludes with various recommendations on steps that should be taken by the international community and States in Southeast Asia to combat piracy and armed robbery against ships.     

Linking Community and Ecosystem Processes: The Role of Minor Species

The link between species and ecosystem functioning is a central issue in ecology. In natural plant communities, the dominant species determine most of the productivity-related processes but what is the function of minor species? A recent hypothesis suggests that after disturbance, minor species facilitate the recruitment and abundance of dominants during re-colonization, thus indirectly determining ecosystem function. We tested this hypothesis using a long-term dataset of annual plant communities in a semiarid shrubland by comparing plant density and biomass from plots in which all vegetation had been removed; plots from which only the dominant (the annual grass Stipa capensis) had been removed, and control plots. In the absence of vegetation, the dominant failed to re-establish during the following growing season. After being removed the dominant re-established similarly to the controls. An ant exclosure experiment excluded the possibility that this was due to seed predation. In an experiment with individual dispersal units of S. capensis, we demonstrated the mechanism by which minor species can control the dominant’s abundance. Minor species indirectly govern ecosystem processes by providing structures facilitating seed soil penetration and thus recruitment of the dominant.     

Marine environmental issues of Southeast Asia: state and development

The seas of Southeast Asia play an important role in the economy of the surrounding countries. The region's constantly expanding coastal population and development has made great demands on marine resources, with growing evidence seen in the further degradation of the marine environment and continued exploitation of living as well as non-living resources. Integrated coastal area management has never been considered in the past while environmental protection measures and policies have largely been at local or national levels. Implementation of regional study programmes less than 10 years ago and ratification of international as well as regional agreements aimed at protecting the marine environment in recent times indicate a more enlightened approach to the problem.