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111.
Effects of Karst Forest Degradation on Pulmonate and Prosobranch Land Snail Communities in Sabah, Malaysian Borneo 总被引:1,自引:0,他引:1
MENNO SCHILTHUIZEN‡ THOR-SENG LIEW BERJAYA BIN ELAHAN† ISABELLE LACKMAN-ANCRENAZ† 《Conservation biology》2005,19(3):949-954
Abstract: Limestone (karst) outcrops in Southeast Asia are rich in land snails. Certain groups of land snails, in particular Prosobranchia species, are restricted to limestone and show a high degree of short-range endemism. Karst habitats are, however, seriously degraded by quarrying, logging, agriculture, and burning. The effect of these disturbances on land snail fauna is unknown, so we studied paired primary and secondary forest localities on six separate limestone hills in Sabah, Malaysian Borneo. Land snails were sampled with a standard protocol and identified to species level. More than 16,000 individuals, belonging to 74 species, were recorded. In most sites, snail diversities did not differ between disturbed and undisturbed plots. However, pulmonate snails were significantly more abundant at disturbed localities than prosobranch snails, whereas abundances for both groups were similar at undisturbed sites. Because Prosobranchia contain many site-endemic species, our findings suggest that continued exposure to these disturbances will eventually lead to extinctions in this group. 相似文献
112.
Multi-temporal satellite imagery from the Moderate Resolution Imaging Spectrometer (MODIS) was used to map the different ecosystems of Southeast Asian (SEA) rice paddies. The algorithm was based on temporal profiles of vegetation strength and/or water content, using MODIS surface reflectance in visible to near-IR range. The results obtained from the analysis were compared to national statistics. Estimated SEA regional rice area was 42 × 106 ha, which agrees with published values. The model performance was dependent on rice ecosystems. Good linear relationships between the model results and the national statistics were observed for rainfed rice. High linear coefficients of determination, R2, were also found for irrigated rice and upland rice, but the model tended to underestimate irrigated rice and overestimate upland rice. However, these high R2 values indicated that the model effectively simulated spatial distribution of these rice areas. These R2 values were either of similar magnitude or larger than those reported in literature, regardless of the rice ecosystem. Poor correlation was observed for deepwater rice. 相似文献
113.
The transparency framework of the Paris Agreement (PA) will be elaborated from the existing arrangements under the UN Framework Convention on Climate Change (UNFCCC). Yet, the capacities of developing countries to regularly report national GHG inventories vary, and their needs for capacity building are closely linked with efforts and achievements of previous inventory preparation. The purpose of this study was to analyze the status and changes in the capacity of 37 developing countries in Asia by using a matrix of capacity-indicators. Indicators were composed for four assessment categories: (1) international engagement of a country in the GHG inventory-related process; (2) institutional capacity to produce a GHG inventory; (3) existing technical capacity available to develop a GHG inventory; and (4) actual technical capacity applied to produce a GHG inventory. The paper also analyzed the scale of international support and variations in meeting with capacity building needs. Eleven countries were identified as having low capacity over time, while 9 improved their capacity. Seventeen countries, including 7 countries with established capacity, continuously had relatively high capacity over time. International support was scarce in the majority of Asian developing countries with the most capacity building needs. Improvements in basic technical capacity available for GHG inventory preparation, such as statistics and the scientific expertise, were found to be a key necessity for countries to respond to the PA’s enhanced transparency framework. Based on these findings, the study recommended increasing support for improvements in basic technical capacity, especially in countries where existing capacity is low and support is limited. Such capacity building efforts are also beneficial for countries to form and implement nationally determined contributions (NDCs) and other economic and development policies. 相似文献
114.
115.
Farmers attempting to subsist in tropical uplands often rely upon unsustainable resource use practices that lead to soil erosion, declining crop yields, and a loss of soil productivity capacity. Other uses of tropical uplands, including logging and conversion of forest to rangelands, have similar results. The undesirable effects of these actions are felt on-site, at the watershed level, and even nationally. Ecological cause-effect relationships are poorly understood, and few examples exist of the successful integration of ecological knowledge with upland development. It is hypothesized that recent results of ecological research could be applied to uplands management so that stable sustainable systems of human use may be established. A second hypothesis is that statistically reliable data can be obtained from experiments in upland situations, although natural variations of soils, weather, and vegetation are great. To test these hypotheses, research involving multinational collaboration among American and Southeast Asian scientists has begun. The objective of the work is to provide credible quantitative information to help policy and decision makers and resident farmers to plan and implement improved practices based on ecological principles.Some findings to date include:
相似文献
1. | Ecological principles are difficult to relate to the practical context of upland agroecosystems. Indeed, the null hypothesis is necessary for planning experiments and demonstrations. |
2. | The signal-to-noise ratio in these field experiments is low, and the detection of changes due to human intervention in soil erosion, nutrient movement, and plant productivity is difficult. |
3. | Obstacles to field research in developing countries include logistic, cultural, political, and institutional factors. It is essential that local land managers participate from the start with scientific researchers in designing experiments. |
4. | Planned collaboration among academic and government scientists facilitates design of relevant research and the implementation of results. |
5. | The idea of ecologically based management has been well received by researchers and government officials in Asia. There is little argument with the logic of the approach. |
6. | Pressures for quick responses to urgent problems in the uplands conflict with the need for careful, long-term, statistically valid scientific research. |
7. | Ecological principles are vaguely understood and poorly articulated in the scientific literature. The transfer and application of ecological science to the developing world would be enhanced by clearer statements of principles. |
116.
于2018年12月(冷季),结合水体现场理化参数和入湖河流,湖泊表层,湖泊垂直分层及出水口各样点水样分析结果对其水化学组成和分布特征以及影响因素进行了研究.结果表明,冷季巴松措水体呈弱碱性.湖区TDS含量较低,平均值仅达107mg/L.湖区平均水温为5.7℃,在水深45~60m范围内存在温度跃变,但变化梯度较小.空间上,各现场理化参数值从入湖河流到湖泊表层且沿垂直方向至最深处均有一定的变化规律,但是这些变化并无显著性差异(P>0.05).巴松措湖泊水体溶解相中,Ca2+和HCO3-为主导离子,分别占阳离子和阴离子总量的80.35%和72.95%.各主要离子浓度在平面空间分布上表现为入湖河流高于湖泊表层,汇入湖泊后趋于平稳的趋势.在垂直空间分布上却呈随水深增加而轻微增大的趋势.巴松措水化学类型为HCO3·SO4-Ca型.流域内受岩石风化作用的影响,特别是碳酸盐岩的风化过程是影响巴松措水化学组成和分布特征的主要控制因素. 相似文献
117.
Surface water pollution in three urban territories of Nepal, India, and Bangladesh 总被引:10,自引:0,他引:10
In South Asian countries such as Nepal, India, and Bangladesh, pollution of rivers is more severe and critical near urban
stretches due to huge amounts of pollution load discharged by urban activities. The Bagmati River in the Kathmandu valley,
the Yamuna River at Delhi, and peripheral rivers (mainly Buriganga River) of Dhaka suffer from severe pollution these days.
The observed dry season average of biochemical oxygen demand (BOD) in all these rivers is in the range of 20–30 mg/liter and
total coliform are as high as 104–105 MPN/100 ml. Per capita pollution load discharge of urban areas has been estimated to be about 31, 19, and 25 gBOD/capita/day
in Bagmati, Yamuna, and the rivers of Dhaka, respectively. Regression analysis reveals pollution loads steadily increasing
nearly in step with the trend in urbanization. The dissolved oxygen (DO) level of the Bagmati and Buriganga rivers is declining
at an average annual rate of nearly 0.3 mg/liter/year. Unplanned urbanization and industrialization occurring in these cities
may be largely responsible for this grave situation. Inadequate sewerage, on-site sanitation, and wastewater treatment facilities
in one hand, and lack of effective pollution control measures and their strict enforcement on the other are the major causes
of rampant discharge of pollutants in the aquatic systems. 相似文献
118.
Land-Use and Land-Cover Change in Montane Mainland Southeast Asia 总被引:12,自引:1,他引:12
This paper summarizes land-cover and land-use change at eight sites in Thailand, Yunnan (China), Vietnam, Cambodia, and Laos
over the last 50 years. Project methodology included incorporating information collected from a combination of semiformal,
key informant, and formal household interviews with the development of spatial databases based on aerial photographs, satellite
images, topographic maps, and GPS data. Results suggest that land use (e.g. swidden cultivation) and land cover (e.g. secondary
vegetation) have remained stable and the minor amount of land-use change that has occurred has been a change from swidden
to monocultural cash crops. Results suggest that two forces will increasingly determine land-use systems in this region. First,
national land tenure policies—the nationalization of forest lands and efforts to increase control over upland resources by
central governments—will provide a push factor making it increasingly difficult for farmers to maintain their traditional
swidden land-use practices. Second, market pressures—the commercialization of subsistence resources and the substitution of
commercial crops for subsistence crops—will provide a pull factor encouraging farmers to engage in new and different forms
of commercial agriculture. These results appear to be robust as they come from eight studies conducted over the last decade.
But important questions remain in terms of what research protocols are needed, if any, when linking social science data with
remotely sensed data for understanding human-environment interactions. 相似文献
119.
亚洲地区环境教育实践的探讨与借鉴 总被引:2,自引:0,他引:2
从环境教育的目标和任务,课程,教材,师资培训,公众参与等角度,分析了亚洲各国际环境教育发展的政策,方法,内容等方面的特色和经验,为我国的地区环境教育事业发展提供借鉴。 相似文献
120.
A. Heil B. Langmann E. Aldrian 《Mitigation and Adaptation Strategies for Global Change》2007,12(1):113-133
Numerical modelling of fire-related smoke haze episodes in Southeast Asia is important for both prediction and assessment of atmospheric impacts, especially when observational data are fragmentary, as is the case in Indonesia. This work describes the atmospheric fate of smoke particles emitted during the 1997 Indonesian fires modelled with a regional atmospheric chemistry model. We established a new fire emission inventory and calculate that 55 teragram (Tg) of particulate matter and 1098 Tg of carbon were released during this fire episode. Our emission estimate is an intermediate value compared with other studies. Utilising different scenarios, we demonstrate the variable atmospheric impacts of surface vegetation fires and peat soil fires separately and also investigate the sensitivity of smoke dispersion to the differing meteorological conditions of an El Niño and a normal year. When peat fires are included in the emission inventory, modelled ambient particle concentrations exceed the ambient air quality standard across transboundary scales. In a scenario including only surface vegetation fires, ambient air quality standards are exceeded only in areas close to the main fires. This scenario demonstrates the prominent role of fires in peat areas in causing regional air pollution episodes. In years with normal meteorological conditions, intermittent precipitation and associated wet deposition during the dry season are predicted to remove most of the particulate emissions close to the sources. Strongly reduced rainfall and generally stronger southeasterly winds during El Niño years provide favourable conditions for larger scale smoke haze pollution. 相似文献