19世纪前柬埔寨由盛到衰的原因分析

本文主要从泰国和越南对柬埔寨的入侵、吴哥王朝的大肆挥霍和穷兵黩武、宗教因素、民族心理因素等方面入手 ,对柬埔寨沦为法国殖民地以前的衰败过程进行了分析 ,揭示了柬埔寨由东南亚地区一个较为强大的国家逐步走向衰落的深刻根源。

Tests to evaluate the ecological impact of treated ballast water on three Chinese marine species

Ballast water has been a topic of concern for some time because of its potential to introduce invasive species to new habitats. To comply with the International Convention for the Control and Management of Ships' Ballast Water and Sediments, members of the International Maritime Organization(IMO) must equip their ships with on-board treatment systems to eliminate organism release with ballast water. There are many challenges associated with the implementation of this IMO guideline, one of which is the selection of species for testing the ecological impacts of the treated ballast water. In the United States, ballast water toxicity test methods have been defined by the United States Environmental Protection Agency. However, the test methods had not been finalized in China until the toxicity test methods for ballast water were established in 2008. The Chinese methods have been based on species from three trophic levels: Skeletonema costatum, Neomysis awatschensis, and Ctenogobius gymnauchen. All three species live in broad estuarine and open sea areas of China; they are sensitive to reference toxicants and acclimatize easily to different conditions. In this paper, the biological characteristics, test processes and statistical analysis methods are presented for the three species. Results indicate that the methods for evaluating these three organisms can be included in the ecological toxicity tests for treated ballast water in China.

Invasion and Morphological Variation of the Non- Indigenous Barnacle Chthamalus challengeri(Hoek, 1883) in Yangshan Port and its Surrounding Areas

Invasive species generally possess unique characteristics that allow them to survive the invasion process in order to es- tablish and spread in new habitats. Successful invaders must resist both physical and physiological stresses associated with the changing environment. A common littoral barnacle, Chthamalus challengeri Hoek, 1883 （Crustacea, Cirripedia）, which is native to Japan, South Korea and northern China, has become established in the high-littoral zone adjacent to Yangshan Port, Shanghai, China. A comparison of the morphology of Chthamlus species from Zhoushan archipelago with previous description indicates the occur- rence of C. challengeri. The new immigrant becomes a dominant species in certain high-intertidal habitats of the adjacent area to of Yangshan Port. C. challengeri was found in part of sampling sites in Zhoushan in 2010; however, it dispersed to all the eleven sam- piing sites in 2012. Densities of C.challengeri had increased over 10 times in the last 2 years, with the highest mean value reaching 39533 ± 6243 ind. m-2 in the new habitat. The specific ratios of both operculum area （Sa） to base area （SA） and average height of pa- rietal plates （H） to length of base （L） revealed that C. challengeri displays morphological changes to resist stronger currents in the new habitats for invasion.

Ballast Water Treatment Methods of International Vessels Docking in Loboc Port, Iloilo City, Philippines

This study delved on the ballast water management methods among international vessels docking at Loboc Port, Iloilo City, Philippines and other factors that are considered during ballast operation. The respondents of this study were the seafarers from the 15 international vessels docking at Loboc Port. The findings of the study revealed that the international vessels docking at Loboc Port used the sequential method, flow-through method, chlorination method, hydrogen peroxide, UV （ultraviolet） irradiation and filtration method in ballasting. In order to prevent transfer of alien invasive species, government authorities such as MARINA （Maritime Industry Authority） and Philippine Coast Guard should strictly monitor and implement the ballast water management methods used by international vessels based on the guidelines set by the IMO （International Maritime Organization）.

Status, Impact and Management of Certain Alien Plant Pests Proven to Be Invasive to Thailand＇s Ecology

Introduction of foreign plants and animals into Thailand＇s ecology has a long history, some arrived accidentally and others had a purpose. As global commerce increases, the issue of invasive alien species has become more urgent in Thailand. These agents are increasingly seen as a threat not only to biodiversity and ecosystem, but also to economic development and human well-being. They reduce yields of agricultural crops, forests and fisheries, decrease water availability, cause costly land degradation, block transport routes and contribute to the spread of disease. It is clear that since trade will not stop, dangerous alien species need to be controlled and managed and the strategies and control measures are to prevent, eradicate, contain, or effectively control the invaders. Implementation of these measures requires appropriate legislation, regulation and procedures. The impact of some invasive alien pests and their management on the agricultural sector of Thailand are presented.

Alien woody plant invasions in natural forests across China

Aims Alien plant invasion has become a major global environmental issue,causing severe economic and ecological damages.Severe invasions have been reported in some regions of China.However,most studies have been conducted at local and provincial levels,and the overall degree of invasion in natural forests across China remains unclear.Here,we explored the biogeographic patterns and their environmental and socioeconomic controls of the invaded alien woody plants in natural forests across the country.Methods We compiled the data of 3573 natural forest plots across the China's Mainland and mapped spatial distribution of alien woody plant invasion.We also used logistic regression models to identify the key socioeconomic and environmental factors that were associated with the observed invasion patterns.Important Findings We found that only 271 plots among 3573 natural forest plots were invaded by alien woody plants,accounting for 7.58%of all plots.Among all 2825 woody plant species across all plots surveyed,only 5 alien species(0.177%)were found.Both human activities and climate factors were related to the observed invasion patterns.Since China’s natural forests are mostly located in remote mountainous areas with limited human disturbance,alien woody plant invasions are less than those reported in North America and Europe.However,with the development of transportation and increased economic activities in mountainous areas,more invasions by alien plants may be expected in the future.Therefore,proactive management and policy making are desired to prevent or slow down the invasion processes.

Landscape Characterization of Sariska National Park (India) and Its Surroundings

Landscape characterization gives an overall information on the status of Land Use and Land Cover （LULC）, changes in its composition and the impact of natural and human influences operating at different spatial and temporal scales. This information can be used to monitor changes in natural forest resources and protected areas, delineate potential conservation areas and can serve in effective management of ecologically fragile landscapes. In the present study, geo-spatial tools were used to characterize the landscape of Sariska National Park and its surroundings. Satellite data was used to prepare LULC maps for 1989 and 2000, change detection analysis and computation of landscape metrics. Climatic data, field records and modeling tools were used to map the potential spread of two invasive species, Prosopis juliflora and Adhatoda vasica. The results show that the forest area increased from 1989 to 2000, indicating better management practices. Landscape metrics （PAFRAC, PLADJ and AI） also support this argument. Improvements in the degraded forest can further enhance this effect. The entire reserve however is suitable for the invasion of P. juliflora and A. vasiea but is more pronounced in Boswellia serrata and Anogeissus pendula - Acacia catechu （open） forests. A detailed landscape characterization map can help forest managers to make important policy decisions concerning issues such as invasive species.