Status and dynamics of Kobresia pygmaea ecosystem on the Tibetan plateau

This paper provides information about the distribution, structure, and ecology of the world's largest alpine ecosystem, the Kobresia pygmaea pastures in the southeastern Tibetan plateau. The environmental importance of these Cyperaceae mats derives from the extremely firm turf, which protects large surfaces against erosion, including the headwaters of the Huang He, Yangtze, Mekong, Salween, and Brahmaputra. The emphasis of the present article is on the climate-driven evolution and recent dynamics of these mats under the grazing impact of small mammals and livestock. Considering pedological analyses, radiocarbon datings, and results from exclosure experiments, we hypothesize that the majority of K. pygmaea mats are human-induced and replace forests, scrub, and taller grasslands. At present, the carrying capacity is increasingly exceeded, and reinforced settlement of nomads threatens this ecosystem especially in its drier part, where small mammals become strong competitors with livestock and the removal of the turf is irreversible. Examples of rehabilitation measures are given.

Arsenic in groundwater and its influence on exposure risks through traditionally cooked rice in Prey Vêng Province, Cambodia

Arsenic (As) contamination of communal tubewells in Prey Vêng, Cambodia, has been observed since 2000. Many of these wells exceed the WHO As in drinking water standard of 10 µg/L by a factor of 100. The aim of this study was to assess how cooking water source impacts dietary As intake in a rural community in Prey Vêng. This aim was fulfilled by (1) using geostatistical analysis techniques to examine the extent of As contaminated groundwater in Prey Vêng and identify a suitable study site, (2) conducting an on-site study in two villages to measure As content in cooked rice prepared with water collected from tubewells and locally harvested rainwater, and (3) determining the dietary intake of As from consuming this rice. Geostatistical analysis indicated that high risk tubewells (>50 µg As/L) are concentrated along the Mekong River's east bank. Participants using high risk tubewells are consuming up to 24 times more inorganic As daily than recommended by the previous FAO/WHO provisional tolerable daily intake value (2.1 µg/kgBW/day). However, As content in rice cooked in rainwater was significantly reduced, therefore, it is considered to be a safer and more sustainable option for this region.

Rice versus fish revisited: On the integrated management of floodplain resources in Bangladesh

Disproportionately little attention has been paid to the dry season trade-off between rice and (inland capture) fish production on the floodplains of Bangladesh, compared to the same trade-off during the flood season. As the rural economy grows increasingly dominated by dry-season irrigated rice production, and floodplain land and water come under ever-increasing pressure during the dry winter months, there is an urgent need to focus attention on these dry months that are so critical to the survival and propagation of the floodplain resident fish, and to the poor people that depend on these fish for their livelihood. This article examines three important dry-season natural resource constraints to floodplain livelihoods in Bangladesh, and finds a common factor at the heart of all three: rice cultivation on lands at low and very low elevations. The article articulates the system interlinkages that bind these constraints and the long-run trend towards irrigated rice cropping on lower-lying lands, and suggests a management approach based on locally tailored strategies to arrest this trend. Apart from its direct relevance to the floodplains of Bangladesh, which support more than 100 million people, these lessons have relevance for river floodplain systems elsewhere in the developing world, notably the Mekong Delta.

A comparative analysis of projected impacts of climate change on river runoff from global and catchment-scale hydrological models

We present a comparative analysis of projected impacts of climate change on river runoff from two types of distributed hydrological model, a global hydrological model (GHM) and catchment-scale hydrological models (CHM). Analyses are conducted for six catchments that are global in coverage and feature strong contrasts in spatial scale as well as climatic and development conditions. These include the Liard (Canada), Mekong (SE Asia), Okavango (SW Africa), Rio Grande (Brazil), Xiangu (China) and Harper's Brook (UK). A single GHM (Mac-PDM.09) is applied to all catchments whilst different CHMs are applied for each catchment. The CHMs typically simulate water resources impacts based on a more explicit representation of catchment water resources than that available from the GHM, and the CHMs include river routing. Simulations of average annual runoff, mean monthly runoff and high (Q5) and low (Q95) monthly runoff under baseline (1961-1990) and climate change scenarios are presented. We compare the simulated runoff response of each hydrological model to (1) prescribed increases in global mean temperature from the HadCM3 climate model and (2)a prescribed increase in global-mean temperature of 2oC for seven GCMs to explore response to climate model and structural uncertainty. We find that differences in projected changes of mean annual runoff between the two types of hydrological model can be substantial for a given GCM, and they are generally larger for indicators of high and low flow. However, they are relatively small in comparison to the range of projections across the seven GCMs. Hence, for the six catchments and seven GCMs we considered, climate model structural uncertainty is greater than the uncertainty associated with the type of hydrological model applied. Moreover, shifts in the seasonal cycle of runoff with climate change are presented similarly by both hydrological models, although for some catchments the monthly timing of high and low flows differs.This implies that for studies that seek to quantify and assess the role of climate model uncertainty on catchment-scale runoff, it may be equally as feasible to apply a GHM as it is to apply a CHM, especially when climate modelling uncertainty across the range of available GCMs is as large as it currently is. Whilst the GHM is able to represent the broad climate change signal that is represented by the CHMs, we find, however, that for some catchments there are differences between GHMs and CHMs in mean annual runoff due to differences in potential evaporation estimation methods, in the representation of the seasonality of runoff, and in the magnitude of changes in extreme monthly runoff, all of which have implications for future water management issues.

Climate change projections and selected impacts for Vietnam

In September 2013, the 5th Assessment Report (5AR) of the International Panel on Climate Change (IPCC) has been released. Taking the 5AR cli-mate change scenarios into account, the World Bank published an earli-er report on climate change and its impacts on selected hot spot re-gions, including Southeast Asia. Currently, dynamical and statistical-dynamical downscaling efforts are underway to obtain higher resolution and more robust regional climate change projections for tropical South-east Asia, including Vietnam. Such initiatives are formalized under the World Meteorological Organization (WMO) Coordinated Regional Dynamic Downscaling Experiment (CORDEX) East Asia and Southeast Asia and also take place in climate change impact projects such as the joint Vietnam-ese-German project “Environmental and Water Protection Technologies of Coastal Zones in Vietnam (EWATEC-COAST)”. In this contribution, the lat-est assessments for changes in temperature, precipitation, sea level, and tropical cyclones (TCs) under the 5AR Representative Concentration Pathway (RCP) scenarios 4.5 and 8.5 are reviewed. Special emphasis is put on changes in extreme events like heat waves and/or heavy precipita-tion. A regional focus is Vietnam south of 16°N. A continued increase in mean near surface temperature is projected, reaching up to 5°C at the end of this century in northern Vietnam un-der the high greenhouse-gas forcing scenario RCP8.5. Overall, project-ed changes in annual precipitation are small, but there is a tendency of more rainfall in the boreal winter dry season. Unprecedented heat waves and an increase in extreme precipitation events are projected by both global and regional climate models. Globally, TCs are projected to decrease in number, but an increase in intensity of peak winds and rain-fall in the inner core region is estimated. Though an assessment of changes in land-falling frequency in Vietnam is uncertain due to difficul-ties in assessing changes in TC tracks, some work indicates a reduction in the number of land-falling TCs in Vietnam. Sea level may rise by 75-100 cm until the end of the century with the Vietnamese coastline experienc-ing 10-15% higher rise than on global average. Given the large rice and aquaculture production in the Mekong and Red River Deltas, that are both prone to TC-related storm surges and flooding, this poses a challenge to foodsecurity and protection of coastal population and assets.

Yield, growth and mortality rate of the Thai river sprat, Clupeichthys aesarnensis, in Sirinthorn Reservoir, Thailand

The Thai river sprat, Clupeichthys aesarnensis Wongratana, is a clupeid with a short life span, and supports artisanal fisheries in a number of reservoirs in the Mekong Basin. The growth parameters, mortality rates and the status of the Thai river sprat in Sirinthorn Reservoir (28 800 ha), NE Thailand (15°N; 105°E), are presented. The fishery is based on lured lift-nets, operated 7–14 days in the new moon period, September to April each year. It was shown that the von Bertalanffy growth function (VBGF) model was L_t (mm) = 78.43[1 − exp{−0.211[t − (−0.7996)]}] and its growth conformed to an isometric pattern. Natural mortality rate (month−¹) was 0.13 month−¹. Total mortality rates ranged from 0.69 to 1.53 month−¹ depending on the weather and the fishing season. Recruitment was continuous throughout the year but peaked in June and July. The yield per recruit model indicated that the exploitation rate of this fishery is probably too high.

Endemic freshwater finfish of Asia : distribution and conservation status

Freshwater finfish species richness and level of endemism in East, and South and South-East Asia that included 17 nations were studied using available databases, and included nation-wise distribution, habitat types, and conservation status. The number of endemic finfish species in the region was 559, belonging to 47 families. Families Cyprinidae and Balitoridae accounted for 43.5% and 16.2% of the total number of endemic species in the region, respectively, followed by Sisoridae (25), Gobiidae (20), Melanotaeniidae (19), and Bagridae (16), and the other 41 families had at least one endemic species. Nation-wise the most number of endemic freshwater finfish species occur in India (191), followed by China (88), Indonesia (84), and Myanmar (60). In India, the endemic species accounted for 26.4% of the native freshwater fish fauna, followed by South Korea (16.9%), the Philippines, (16.3%) and Myanmar (15.7%).

Statistically significant relationships discerned between the number of indigenous and endemic species richness to land area (X_la in 10³ km²) of the nations in the region were, Y_in = 218.961 Ln(X_la) – 843.1 (R² = 0.735; P < 0.001) and Y_e = 28.445 Ln X_la−134.47 (R² = 0.534; P < 0.01), respectively, and between indigenous and endemic species richness was Y_e = 0.079X_n− 1.558 (R² = 0.235; P < 0.05).

The overall conservation status of endemic finfish in Asia was satisfactory in that only 92 species were in some state of vulnerability, of which 37 species (6.6%) are endangered or critically endangered. However, the bulk of these species (83.7%) were cave- and or lake-dwelling fish. However, nation-wise, the endemic freshwater finfish fauna of the Philippines and Sri Lanka, based on the imperilment index, were found to be in a highly vulnerable state. Among river basins, the Mekong Basin had the highest number of endemic species (31.3%). The discrepancies between databases are highlighted and the need to consolidate information among databases is discussed. It is suggested that the Mekong Basin be considered as a biodiversity hotspot, and appropriate management strategies be introduced in this regard.

Microsatellites revealed no genetic differentiation between hatchery and contemporary wild populations of striped catfish, Pangasianodon hypophthalmus (Sauvage 1878) in Vietnam

Aquaculture of the striped catfish, Pangasianodon hypophthalmus (Sauvage 1878), in Vietnam has become one of the fastest growing primary food production sectors in the world. Although a demand on quantity of fingerlings is currently reached, it is likely that the long term quality of the stocks may be uncertain due to lacking of genetic broodstock management measures. The present study employed five microsatellite loci to investigate levels of genetic variation of the stripped catfish of the current wild stocks as well as of the selected hatcheries in Vietnam. The study included four hatchery populations and two wild populations spawned in 2005 in the Mekong and Bassac Rivers, and one wild population (spawned in 2006) in the Bassac River. The results showed no genetic differentiation among populations as revealed by F_ST and a model-based clustering method. AMOVA also showed no genetic differentiation between pooled wild and pooled hatchery populations while variation within groups was significant. Genetic variation of wild (mean number of alleles per locus, A = 4.80–6.20; allelic richness, A_r = 4.54–5.06; mean effective number of alleles per locus, A_e = 2.86–3.20; observed heterozygosity, H_o = 0.62–0.65; expected heterozygosity, H_e = 0.62–0.64) and hatchery populations (A = 4.60–5.20; A^_r = 4.10–4.83; A_e = 2.80–3.11; H_o = 0.61–0.66; H_e = 0.61–0.64) were not statistically different. There were no evidences for recent genetic bottleneck in all populations. Therefore it is implied that the hatchery stocks of striped catfish in Vietnam were founded from sufficient numbers of brooders and current population size is large. The domestication process is in an early stage.

Patterns of use and exchange of genetic resources of the striped catfish Pangasianodon hypophthalmus (Sauvage 1878)

The present paper reviews the use and exchange of genetic resources of the migratory freshwater fish Pangasianodon hypophthalmus (Sauvage 1878) (the striped or sutchi catfish). This species is naturally distributed in the Mekong River and Chao Phraya River basins, and is cultured in several countries, but current production occurs predominantly in the Mekong Delta, Vietnam. Catfish aquaculture in Vietnam has evolved from extensive systems using wild-caught seed to an intensified farming system that is entirely dependent on hatchery-produced seed. Genetic improvement programmes on catfish have started in Vietnam, but are still in their infancy. Genetic studies have revealed several subpopulations of the species. Apart from selective breeding and the production of hybrids with closely related species, no other technologies have been applied to improve the performance of catfish. The use and exchange of P. hypophthalmus genetic resources have brought benefits to rural communities. Aquaculture development of catfish has evolved from being seen as an exploitation of natural resources to an activity that can reduce pressure on wild fish populations. Management of aquaculture stocks need to be rationalised to minimise the potential impacts it might cause to wild populations.

Thai river sprat : biology and management in Sirinthorn Reservoir, Thailand

The Thai river sprat (Clupeichthys aesarnensis) is a short-lived clupeid, which supports an artisanal fishery in a number of reservoirs in the Lower Mekong Basin. This study presents the C. aesarnensis biology, population dynamics and its fishery in Sirinthorn Reservoir, NE Thailand. C. aesarnensis fishery management schemes are also proposed.

Strong population genetic structure and its management implications in the mud carp Cirrhinus molitorella, an indigenous freshwater species subject to an aquaculture and culture-based fishery

This study investigated population genetic structure and diversity of mud carp Cirrhinus molitorella, a species widely used in aquaculture and culture-based fisheries in China and Mekong River riparian countries. Seven newly developed and one published microsatellite DNA markers were used to analyse samples from six wild locations, four hatchery broodstocks and one farmed site from the Mekong, Red and Pearl Rivers. Significant genetic structure was detected in C. molitorella, with isolation-by-distance being a strong force in the Mekong. Pair-wise F_ST, Fisher's exact tests for population differentiation, permutation tests and individual-based structure analysis all support the recognition of a sample originating from Toul Krasaing Lake (Cambodia) and one between Kratie and Stung Treng (Cambodia) as distinct from the remainder of the sampled range. Samples from the main upper Mekong and the Nam Khan River were significantly differentiated, but on a time scale inferred to be short (i.e. by genetic drift, not sufficient for evolution of new microsatellite alleles). The Mekong stock of C. molitorella was strongly differentiated from those from the Red and Pearl Rivers, inferred to be on an evolutionary time scale. Finer-scale sampling is warranted to further improve the understanding of genetic interactions among fish from the Mekong and its tributaries. Detailed studies on the ecology of C. molitorella (e.g. migration pathways and preferred spawning habitats) would provide useful information to explain the patterns of genetic structure detected here, and deepen insights about evolutionary distinctiveness of the population units.

Cultural heritage and development in South East Asia

This chapter discusses research undertaken into the developmental role of museums and heritage sites in Thailand and the Greater Mekong Subregion, a geographical area that also includes Cambodia, Laos PDR and Myanmar. It contextualizes an international project, the Lampang Temples Project, to explore the potential role that museums and heritage sites can play in place-based development work, particularly in an Asian context where sacred places are simultaneously valued by local members of the community and as desinations for religious pilgrims and international tourists. The discussion of the Lampang Temples Project is located within an understanding of the international discourse concerning the roles of museums in development, including those contributions to the discourse that have originated in the Asia-Pacific region. It is also situated within an understanding of the roles of international agencies and local governments in the promotion of programmes and infrastructure for the preservation of Buddhist heritage and the relationship of this development strategy with tourism. Furthermore, due to the participatory and observational experience of the authors in the Lampang Temples Project, the chapter also considers the issues involved in applying cross-cultural pedagogies to the management of cultural tourism sites, including UNESCO World Heritage Sites. The results of the Lampang Temples Project support the contention that colaborative training models and pedagogies can be adapted, provided that differing cultural contexts and suppositions are appropriately articulated and integrated. Further, it suggests that this type of collaborative approach to the management of cultural tourism sites has the potential to play an important role in Buddhist heritage development processes.

Climate change impacts : challenges for aquaculture

In spite of all the debates and controversies, a global consensus has been reached that climate change is a reality and that it will impact, in diverse manifestations that may include increased global temperature, sea level rise, more frequent occurrence of extreme weather events, change in weather patterns, etc., on food production systems, global biodiversity and overall human well being. Aquaculture is no exception. The sector is characterized by the fact that the organisms cultured, the most diverse of all farming systems and in the number of taxa farmed, are all poikilotherms. It occurs in fresh, brackish and marine waters, and in all climatic regimes from temperate to tropical. Consequently, there are bound to be many direct impacts on aquatic farming systems brought about by climate change. The situation is further exacerbated by the fact that certain aquaculture systems are dependent, to varying degrees, on products such as fishmeal and fish oil, which are derived from wild-caught resources that are subjected to reduction processes. All of the above factors will impact on aquaculture in the decades to come and accordingly, the aquatic farming systems will begin to encounter new challenges to maintain sustainability and continue to contribute to the human food basket. The challenges will vary significantly between climatic regimes. In the tropics, the main challenges will be to those farming activities that occur in deltaic regions, which also happen to be hubs of aquaculture activity, such as in the Mekong and Red River deltas in Viet Nam and the Ganges-Brahamaputra Delta in Bangladesh. Aquaculture in tropical deltaic areas will be mostly impacted by sea level rise, and hence increased saline water intrusion and reduced water flows, among others. Elsewhere in the tropics, inland cage culture and other aquaculture activities could be impacted by extreme weather conditions, increased upwelling of deoxygenated waters in reservoirs, etc., requiring greater vigilance and monitoring, and even perhaps readiness to move operations to more conducive areas in a waterbody. Indirect impacts of climate change on tropical aquaculture could be manifold but are perhaps largely unknown. The reproductive cycles of a great majority of tropical species are dependent on monsoonal rain patterns, which are predicted to change. Consequently, irrespective of whether cultured species are artificially propagated or not, changes in reproductive cycles will impact on seed production and thereby the whole grow-out cycle and modus operandi of farm activities. Equally, such impacts will be felt on the culture of those species that are based on natural spat collection, such as that of many cultured molluscs. In the temperate region, global warming could raise temperatures to the upper tolerance limits of some cultured species, thereby making such culture systems vulnerable to high temperatures. New or hitherto non-pathogenic organisms may become virulent with increases in water temperature, confronting the sector with new, hitherto unmanifested and/or little known diseases. One of the most important indirect effects of climate change will be driven by impacts on production of those fish species that are used for reduction, and which in turn form the basis for aquaculture feeds, particularly for carnivorous species. These indirect effects are likely to have a major impact on some key aquaculture practices in all climatic regimes. Limitations of supplies of fishmeal and fish oil and resulting exorbitant price hikes of these commodities will lead to more innovative and pragmatic solutions on ingredient substitution for aquatic feeds, which perhaps will be a positive result arising from a dire need to sustain a major sector. Aquaculture has to be proactive and start addressing the need for adaptive and mitigative measures. Such measures will entail both technological and socio-economic approaches. The latter will be more applicable to small-scale farmers, who happen to be the great bulk of producers in developing countries, which in turn constitute the “backbone’ of global aquaculture. The sociological approaches will entail the challenge of addressing the potential climate change impacts on small farming communities in the most vulnerable areas, such as in deltaic regions, weighing the most feasible adaptive options and bringing about the policy changes required to implement these adaptive measures economically and effectively. Global food habits have changed over the years. We are currently in an era where food safety and quality, backed up by ecolabelling, are paramount; it was not so 20 years ago. In the foreseeable future, we will move into an era where consumer consciousness will demand that farmed foods of every form will have to include in their labeled products the green house gas (GHG) emissions per unit of produce. Clearly, aquaculture offers an opportunity to meet these aspirations. Considering that about 70 percent of all finfish and almost 100 percent of all molluscs and seaweeds are minimally GHG emitting, it is possible to drive aquaculture as the most GHG-friendly food source. The sector could conform to such demands and continue to meet the need for an increasing global food fish supply. However, to achieve this, a paradigm shift in our seafood consumption preferences will be needed.

Flood forecasting in large rivers with data-driven models

Results from the application of adaptive neuro-fuzzy inference system (ANFIS) to forecast water levels at 3 stations along the mainstream of the Lower Mekong River are reported in this paper. The study investigated the effects of including water levels from upstream stations and tributaries, and rainfall as inputs to ANFIS models developed for the 3 stations. When upstream water levels in the mainstream were used as input, improvements to forecasts were realized only when the water levels from 1 or at most 2 upstream stations were included. This is because when there are significant contributions of flow from the tributaries, the correlation between the water levels in the upstream stations and stations of interest decreases, limiting the effectiveness of including water levels from upstream stations as inputs. In addition, only improvements at short lead times were achieved. Including the water level from the tributaries did not significantly improve forecast results. This is attributed mainly to the fact that the flow contributions represented by the tributaries may not be significant enough, given that there could be large volume of flow discharging directly from the catchments which are ungauged, into the mainstream. The largest improvement for 1-day forecasts was obtained for Kratie station where lateral flow contribution was 17 %, the highest for the 3 stations considered. The inclusion of rainfall as input resulted in significant improvements to long-term forecasts. For Thakhek, where rainfall is most significant, the persistence index and coefficient of efficiency for 5-lead-day forecasts improved from 0.17 to 0.44 and 0.89 to 0.93, respectively, whereas the root mean square error decreased from 0.83 to 0.69 m.