Asian Ecosystems Research Articles

The regional carbon budget of East Asia simulated with a terrestrial ecosystem model and validated using AsiaFlux data

The regional-scale carbon budget of East Asia was evaluated using a process-based model of terrestrial carbon cycle driven by high-resolution input data. The model was developed for integrating observational data and validated with net ecosystem CO 2 exchange (NEE) data from AsiaFlux sites. For each 30-s × 30-s (about 1 km 2) grid cell, the ecosystem model was used to simulate daily photosynthesis, respiration, decomposition, and ecosystem growth. Such high-resolution simulation allowed us to explicitly capture land surface heterogeneity and to ameliorate the scale-gap in comparison between simulated and observed fluxes. The simulated NEE was compared with data from three AsiaFlux sites (Tomakomai, Fujiyoshida, and Takayama) during the period 2000–2005, with results suggesting that the model retrieved the carbon budget characteristics, such as differences in seasonal sink/source variation among biome types. The regional simulation indicated that terrestrial ecosystems in East Asia had a net primary productivity of 996 Tg C year −1 and a net ecosystem productivity of 58 Tg C year −1 (1 Tg = 10 12 g), indicating a net carbon sink equivalent to 11% of regional anthropogenic emissions. Interannual variability in the carbon budget was evident: East Asian ecosystems absorbed more carbon in 2002, the warmest year with a longer growing period. Based on the regional result, the spatial representativeness of the AsiaFlux sites was investigated with regard to climatic condition and carbon budgets. This model provides a reliable means for scaling-up from site to regional scales, and the findings have implications for observational studies and ecosystem management related to carbon sequestration and climate change mitigation.

Climate Change and Ecosystems of Asia With Emphasis on Inner Mongolia and Mongolia

Climate Change and Ecosystems of Asia With Emphasis on Inner Mongolia and Mongolia

“The Cretaceous Tetori biota in Japan and its evolutionary significance for terrestrial ecosystems in Asia” [Cretaceous Research 27 (2006) 199–225]—Discussion

Matsukawa et al. present a new interpretation of the age and geological correlation within the Tetori Group. Comparison of their data with our own studies and literatures, we comment on some problems remain unsolved in their paper, such as (1) stratigraphy of the Takinamigawa area, where various fossils including dinosaurs were recovered; (2) recognition of the Akaiwa and Tamodani floras, constituents of the Tetori-type flora; (3) geological correlation of the Tetori Group between the Mt. Hakusan and Kuzuryugawa regions. Further combination of lithostratigraphy and other correlation methods is required to improve the understanding of the stratigraphy of the Tetori Group.

Wetlands Ecosystems in Asia: Function and Management ‐ Edited by M. H. Wong

Wetlands Ecosystems in Asia: Function and Management ‐ Edited by M. H. Wong

The Cretaceous Tetori biota in Japan and its evolutionary significance for terrestrial ecosystems in Asia

Cretaceous nonmarine deposits are widely distributed on the Asian continent and include various kinds of zoo- and phyto-assemblages. The Tetori Group is one of the most important Mesozoic terrestrial deposits in East Asia, and for this reason its geology, stratigraphy, and biota have been studied intensively by our group for more than a decade. We present the main results herein. We confirm that formations as lithostratigraphic units are the best geological correlation tools for the Tetori Group and the best tools for a geological mapping of the group. Although subgroups have previously been used for correlation, proper designation and evaluation of subgroups is required if they are to be used effectively, and we show that previous geological correlation of the Tetori Group has been confused by inappropriate definition of these subgroups. We located fossil localities including reported zoo- and phyto-assemblages in the framework of formations correlated by our stratigraphy. The occurrence of zoo-assemblages was probably controlled by environments (i.e., most are in situ), but phyto-assemblages were mostly transported and rapidly buried by high-energy river systems. Although two distinct dinosaur faunas and four floras have been named for the zoo- and phyto-assemblages in the Tetori Group, in reality there is only one Tetori Dinosaur Fauna and one Tetori Flora, as proved by careful correlation. Two types of zoo-assemblages co-occur in the Tetori Group: vertebrate species whose ancestors flourished in the Jurassic (as found in China), and their descendants from the Late Cretaceous. As the latter modern type of assemblage is more abundant than the former, changeable environments at the continental margin probably accelerated evolution of more modern species. We can employ nonmarine molluscan species as geological correlation tools in some cases, i.e., when their taxon ranges are well-confirmed by independent evidence. However, because freshwater molluscan species and terrestrial vertebrate species had many opportunities to move to optimum habitat as environments changed through time on the Cretaceous Asian continent, their correlation potential is uncertain. Many nonmarine molluscan species from the Japanese and Chinese Cretaceous had their stratigraphic occurrences controlled by changing environments.

Regional carbon dynamics in monsoon Asia and its implications for the global carbon cycle

Data on three major determinants of the carbon storage in terrestrial ecosystems are used with the process-based Terrestrial Ecosystem Model (TEM) to simulate the combined effect of climate variability, increasing atmospheric CO 2 concentration, and cropland establishment and abandonment on the exchange of CO 2 between the atmosphere and monsoon Asian ecosystems. During 1860–1990, modeled results suggest that monsoon Asia as a whole released 29.0 Pg C, which represents 50% of the global carbon release for this period. Carbon release varied across three subregions: East Asia (4.3 Pg C), South Asia (6.6 Pg C), and Southeast Asia (18.1 Pg C). For the entire region, the simulations indicate that land-use change alone has led to a loss of 42.6 Pg C. However, increasing CO 2 and climate variability have added carbon to terrestrial ecosystems to compensate for 23% and 8% of the losses due to land-use change, respectively. During 1980–1989, monsoon Asia as a whole acted as a source of carbon to the atmosphere, releasing an average of 0.158 Pg C per year. Two of the subregions acted as net carbon source and one acted as a net carbon sink. Southeast Asia and South Asia were sources of 0.288 and 0.02 Pg C per year, respectively, while East Asia was a sink of 0.149 Pg C per year. Substantial interannual and decadal variations occur in the annual net carbon storage estimated by TEM due to comparable variations in summer precipitation and its effect on net primary production (NPP). At longer time scales, land-use change appears to be the important control on carbon dynamics in this region.

Conservation of freshwater biodiversity in Oriental Asia: constraints, conflicts, and challenges to science and sustainability

Freshwater ecosystems in Asia are under grave threat. Large and growing human populations and the rapid pace of development have led to the degradation of natural environments throughout the region. Conservation of freshwater biodiversity faces particular challenges because of a lack of public awareness of its magnitude and importance. Even taxa with high public-relations value, such as fishes, are rather poorly known, and the variety of other animals associated with lakes and riverine wetlands, including charismatic and endangered megafauna, seems to have escaped wide attention. The rate and extent of environmental change in Asia are having impacts on the aquatic biota that may be greater than anywhere else on the planet. Particular threats include water pollution, from point and nonpoint sources, which is almost ubiquitous; overharvest of fishes, turtles, and crocodilians; flow regulation and impoundment of rivers; as well as drainage basin degradation and climate change. Many lakes have been so modified by human activities that they function as enormous fishponds, and the introduction of exotic species (especially, but not only, fishes) or the translocation of native taxa has contributed to the extinction of endemic species in isolated drainage basins. The prognosis is grim, and we can anticipate a loss in biodiversity and homogenization of the regional biota. Reversal of these trends will require a change in focus by limnologists and water-resource managers, and the urgent adoption of a conservation agenda for freshwater science in Asia.

Biogeochemical approaches to assessment of East Asian ecosystem sensitivity to acid depositon

We used the critical load (CL) concept to calculate ecosystem response to acid deposition in East Asia. The calculation of critical loads to assess the sensitivity of ecosystems to acidic deposition was made using a biogeochemical approach, which took into consideration both rates of biogeochemical cycling and temperature responses. On the basis of these data the soil-biogeochemical mapping has been carried out for the area of East Asia and the CL values for acid-forming compounds have been calculated using modified steady-state mass balance (SSMB) equations. In the north-eastern ecosystems of the Asian part of Russia these values of critical loads for N [CL(N)] and S [CL(S)] compounds are shown to be less than in Europe due to peculiarities of climate, soil and vegetation. The minimum values of both CL(N) and CL(S) are 300 eq/ha/yr. These values are occasionally lower than for corresponding European ecosystems. For the south-eastern ecosystems of the northern part of Thailand the minimum values are 700 eq/ha/yr. The minimum CL values (<200 eq/ha/yr) occur in more than 75% of the studied Thai area.

Variation of Ecosystems over East Asia in Association with Seasonal, Interannual and Decadal Monsoon Climate Variability

Nearly half of the global low latitudes are characterized by a monsoon climate. This paper first analyzes the global spatial distribution of the rate of climate variation based on precipitation data. Results show that the monsoon regions in Asia and West Africa, and to a lesser extent in Australia, have the highest rate of climate variation on all time scales. These variations are manifested as seasonal jumps, high interannual and interdecadal variabilities, and abrupt changes between climate regimes. The monsoon regions are covered by various types of ecosystems which account for a large portion of the global biomass. Further analyses of the variations of ecosystems in the Asian region and their relationships with the monsoon climate have shown that the spatial and temporal variabilities of ecosystems are characterized by their strong response to variations in monsoon rainfall, one of the major energy flows in terrestrial ecosystems. The high rate of variation in monsoon climate strongly influences variation in Asian ecosystems. Changes in Asian ecosystems seem to be mainly driven by variations in monsoon climate over various time scales. This observation has led to the proposal of ‘monsoon-driven ecosystems’ in Asia.

Termite species richness in fire-prone and fire-protected dry deciduous dipterocarp forest in Doi Suthep-Pui National Park, northern Thailand

Fire is prevalent in the dry deciduous forests of south-east Asia, the majority of fires being man-made (Stott 1988). In Thailand, the 10-19% estimated extent of annual burning of dry deciduous dipterocarp forest (1984-1986 data on total estimated area burned each year; Settarak et al. 1987) is thought to be a severe under-estimate (Kanjanavanit 1992). The interaction of fire and termites is poorly known for Asian ecosystems, but African studies show they have complementary roles in the removal of wood and leaf litter (Collins 1981, Trapnell et al. 1976). Termites are the dominant arthropod decomposers in tropical forests (Collins 1983) and savannas (Collins 1981, Holt 1987), and are important mediators of carbon flux (Jones 1990, Lawton et al. 1996). Furthermore, these functions are dependent on the species assemblage structure of the termite community (Lawton et al. 1996). To date, the only study of the effects of fire on termite species richness and abundance is from Australia (Abensperg-Traun & Milewski 1995). Here, a preliminary survey of species richness of termites in fireprotected and fire-prone deciduous forest in northern Thailand is presented. The study suggests that the fungus-growing Macrotermitinae have a greater species richness, under certain seasonal fire regimes, compared to those in areas under complete fire protection. Species richness estimates were made for two dry deciduous dipterocarp forest sites: A, fire-protected and; B, unprotected, fire-prone, in Doi Suthep-Pui National Park, near Chiang Mai, northern Thailand. Site A covered a 10 ha

Integrated scenarios of acidification and climate change in Asia and Europe

Two integrated assessment models, one for climate change on a global scale (IMAGE 2) and another for the regional analysis of the impacts of acidifying deposition (RAINS), have been linked to assess the impacts of reducing sulphur emission on ecosystems in Asia and Europe. While such reductions have the beneficial effect of reducing the deposition of acidifying compounds and thus the exceedance of critical loads of ecosystems, they also reduce the global level of sulphate aerosols and thus enhance the impact of increased emissions of greenhouse gases, and consequently increase the risk of potential vegetation changes. The calculations indicate that about 70% of the ecosystems in Asia would be affected by either acid deposition or climate change in the year 2100 (up from 20% in 1990) for both sulphur emission scenarios (controlled and uncontrolled), whereas in Europe the impacted area would remain at a level of about 50%, with a dip early next century. More generally, the effects of reducing sulphur emissions and thus enhancing climate change would about balance for the Asian region, whereas for Europe the desirable impact of sulphur emission reductions would greatly outweigh its undesirable effects.

Sustaining Food Security for Rainfed Ecosystems in Asia

Sustaining Food Security for Rainfed Ecosystems in Asia

Asian Perceptions of Nature: A Critical Approach.

Sacred trees and haunted forests - Indonesia sociopolitical structures and the Southeast Asian ecosystems nature as the virgin forest - Sri Lankan farmers' perspective nature conservation in Northern Pakistan Japanese advertising nature - ecology, women, fashion, art culture in Japanese nature Feng-shui and the Chinese perception of nature.