/kloc-Modern industrial civilization since the 0/8th century has not only created enormous material wealth for human society, but also caused unprecedented damage to the natural environment, resulting in the deterioration of the relationship between man and the natural environment. Especially since 1950s, with the development of economy and the acceleration of industrialization, environmental pollution and ecological destruction have become increasingly serious. A series of environmental problems, such as greenhouse effect, ozone layer destruction, acid rain area expansion, natural resource shortage, soil erosion, land degradation, soil desertification, flood disaster, water pollution and air pollution, and environmental pollution incidents in developed countries, make our planet face more and more serious challenges and threats of ecological environmental problems and become the earth. The ecological environment has become one of the most concerned problems of mankind in the new century. In order to solve these problems, human beings began to understand the structure, function and process of ecosystem more deeply, and gradually carried out ecological environment research at different scales. In recent years, with the deepening of the understanding of ecological environment problems and the development of modern information technology, some new development trends have appeared in ecological environment research.

1. The problems studied are more complicated and comprehensive.

Ecosystem is a complex system of nature, society and economy, which is influenced by many factors and shows complexity and uncertainty. With the growth of population and social economy, the progress of science and technology and the enhancement of human ability to develop resources, the pressure on the ecological environment system is increasing day by day, the ecological environment balance is destroyed, and the ecological environment crises faced by people are endless, and various ecological environment problems are intertwined, making the ecological environment problems more complex and comprehensive. Therefore, the study of ecosystem should be a comprehensive study. Only through comprehensive research can we correctly understand the relationship between different time and space scales and different types of ecosystems, and make an accurate evaluation, thus guiding human beings to make wise ecological decisions (Tian Yongzhong, Yue Tianxiang, 2003).

2. The long-term and regionalization of the space-time scale of the ecological environment research object.

Since the publication of UN Agenda 2 1.992, the sustainable development strategy combining environmental issues with economic and social development has been widely accepted by all countries in the world. In the face of complex and comprehensive ecological environment problems, short-time scale and ecological environment research aimed at local problems or a scheme can no longer explain complex and comprehensive ecological environment problems and phenomena, and can not meet the needs of regional economic development and social coordination (HarropDO, NixonJA, 1999.FortlageCA,1990); It is required to carry out long-term ecological environment positioning research and network research, succession analysis and early warning research, and carry out large-scale sustainable ecosystem research, including global, national, provincial or regional spatial levels (Wang Genxu et al., 200 1). At present, people's focus is mainly on regional ecological environment (such as soil erosion, desertification, water resources, water environment and sustainable development). ), and the study of regional ecological environment has gradually become the focus of many scholars.

3. The research methods tend to be quantitative and modern.

In the past, the research on ecological environment was mainly qualitative description. With the development of ecological research from the study of system structure, state and function to the study of ecological process, the research problems are more complex and comprehensive, the space-time scale of research objects is expanding and information technology is improving, and the ecological environment research based on ecosystem and region is gradually becoming quantitative. Traditional statistical methods have been unable to complete this work, and some new technical means are urgently needed to support ecological research (JocelynKaiser, 200 1). Researchers hope to simulate and predict the present situation and future development trend of ecological environment system with the help of mathematical models; It is hoped that modern remote sensing technology and GIS technology can be used to monitor and analyze ecological environment phenomena.

4. The purpose of the study turned to the management and decision-making of eco-environmental system.

In the past, the main purpose of ecological environment research was to explain the phenomena and laws of ecological environment and analyze the structure and function of ecological environment system. At present, ecological environment research pays more and more attention to the study of ecological process, the value of ecological environment system and its service function, and the sustainable utilization and protection of ecological environment resources. Therefore, the purpose of research began to shift from adapting to ecosystem to scientific management and decision-making of eco-environmental system.

The above-mentioned development trend of ecological environment research makes modern ecological environment research gradually enter a stage based on long-term networked observation, with quantitative and modern information technology as the research means and the goal of establishing a regional sustainable ecological environment system. Modern "3S" theories and technologies-remote sensing (RS), geographic information system (GIS) and global positioning system (GPS) are being deeply and widely applied to the study of ecological environment at different time and space scales. In particular, it has become an important development trend to establish a digital ecological monitoring system in a large-scale watershed (the spatial scale is greater than 10000km2 or even the whole continent) and build a digital watershed (Liu Yingmin, 2006).

The ecological environment is rich in information and covers a wide range. Ecological problems are closely related to geographical factors and usually have strong geographical or geographical distribution characteristics. Therefore, it is difficult to grasp the comprehensive information of the ecological environment and make systematic dynamic monitoring and scientific decision only by conventional investigation, monitoring and data collation. The application of "3S" technology in ecological environment monitoring has the following advantages (Xie Tracking, 2003):

(1) Remote sensing technology can quickly, accurately and objectively reflect the historical and realistic changes of ecological environment from macro to micro, and obtain accurate synchronous data. GPS technology can realize air-ground registration and accurate positioning, overcome the shortcomings of traditional ecological environment monitoring technology and methods, such as small scope, poor status, insufficient information and low positioning accuracy, obtain comprehensive and rich information, and realize the integration of various elements of ecological environment.

(2)GIS technology can comprehensively manage, comprehensively analyze, predict and timely release ecological environment information, which overcomes the shortcomings of traditional technical analysis methods, realizes the integrated analysis and comprehensive processing of ecological environment information space and attribute information, improves the accuracy of ecological environment analysis and evaluation, and also realizes the simulation and prediction of ecological environment evolution, so as to timely adjust management schemes and formulate corresponding management measures to curb the development of ecological environment damage.

(3) "3S" technology has the advantages of high efficiency, low cost, high precision and wide application in ecological environment monitoring and analysis, and is superior to traditional methods in all aspects.