侵蚀地区植被生态动力学模型

研究侵蚀地区的植被在水力侵蚀和各种生态应力以及人类活动影响下的演变规律 ,建立了植被生态动力学模型。将作用于植被的各种生态应力分成长期、短期和瞬时应力 ,给出了它们的定量表达式 ,并且统一在植被生态动力学方程中 ;同时进一步得出了动力学耦合方程组的理论解。该模型应用于金沙江支流小江流域 ,结果较好地描述了流域的植被生态演变过程与侵蚀过程的关系 ,说明了治理强度和控制侵蚀对植被发育的重要性。

The Application of Ecosystem Dynamic Model in Xiamen Bay

This paper is to establish a nitrogen and phosphorus nutrients cycle-based numerical model of ecological dynamics for Xiamen Bay on the basis of the existing three-dimensional barocline hydrodynamic model. The calculation results show that the estuarine district of Jiulongjiang estuary has the highest inorganic nitrogen concentration followed by the West Harbor, which demonstrates that Jiulongjiang River is the main input source of inorganic nitrogen in Xiamen Bay. The West Harbor has relatively high concentration of nutrients caused by the huge land pollution emission and its own poor water exchange capacity; while the distribution rules of phytoplankton biomass correspond with those of phosphates, demonstrating Xiamen Bay＇s phytoplankton controlled by phosphorus; the haloplankton biomass differs slightly, presenting the gradual reduction from the interior part to the exterior part of the bay.

Uncertainty Analysis of Static Coulomb Stress Change Induced by Earthquake-A Case Study on the 2008 M_S8.0 Wenchuan Earthquake

Static Coulomb stress change induced by earthquake slip is frequently used to explain earthquake activities and aftershock distribution.However,some parameters for the Coulomb stress calculation are unable to be well constrained from laboratory experiments and field observations.Different parameters may directly affect the pattern of static Coulomb stress.The static Coulomb stress changes induced by the Wenchuan earthquake calculated by six research groups are not consistent with each other.To investigate how the parameters affect the calculation results,we change the parameters in turn through modeling and compare the results of different calculation parameters.We find that gravity,position and strike of receiver faults have little influence on coseismic Coulomb stress calculations,but other parameters can change the value and sign of the results in various degrees especially around the earthquake rupture plane.Therefore the uncertainty analysis of static Coulomb stress change induced by earthquake should be taken into consideration in the earthquake hazard analysis.

植被-侵蚀动力学的初步探索和应用

植被侵蚀动力学是一个新的边缘学科,研究流域植被与侵蚀在人类活动影响下的演变规律.讨论了作用于植被的各种生态应力,给出了定量表达式并且统一在植被-侵蚀动力学方程组中.推导得出了动力学方程组的理论解并且用于模拟黄土高原安家沟流域和云南小江流域的植被侵蚀演变过程,结果表明动力学方程组精确地模拟了实际演变过程.利用动力学方程组和特征参数作出了植被侵蚀状态图,由此可以预测在停止人类干预后的植被发展趋势,说明了有效治理所需的治理强度和控制侵蚀对植被发育的重要性.植被侵蚀状态图还说明在雨量较丰、气温较高的云南高原小江流域,减少侵蚀是改善植被的重要措施,植被改善后比较稳定.而在比较干旱、水土流失严重的黄土高原上,增加植被能够明显地减少侵蚀,但控制侵蚀对于促进植被发育没有太大的作用.即使植被已经大大改善,仍然不稳定,还需要不断地护理才能维持植被的良性发育.

西藏与内地区域发展成本差异比较

运用生态应力指数计算法、国民经济核算方法和典型指标对比法,对西藏与内地以及三大地带、七大经济区等整体和不同产业的发展成本进行了分析,结果显示,西藏与内地整体以及三大地带、七大经济区的发展成本存在显著差异,三种计算方法计量出的西藏经济发展成本与全国平均水平的差异具有一致性,但不同计算方法下不同产业的发展成本及其与全国平均水平的差异则比较大。

Research Progress in Ecological Carrying Capacity: Implications, Assessment Methods and Current Focus

In recent years, rapid global urbanization accompanied by rapid economic growth has resulted in increasingly serious eco-environmental problems such as land degradation and pollution. As a society, we are gradually realizing the role of environmental protection and ecologically-focused construction in promoting sustainable development. As an important method for assessing sustainable development, ecological carrying capacity（ECC） has become a powerful tool for investigating sustainable development and assessing eco-environmental problems. Based on results from a large number of previous studies in this discipline, we summarized and generalized the implications, main assessment methods, and key research domains of ECC. Deficiencies and future trends in ECC research are identified. In terms of implications, ECC can be roughly defined into the perspectives of environmental change, human effects on ecological systems, and holistic ecological systems. The primary assessment methods and models can be classified in accordance with these three perspectives, including ecological footprint method, ecosystem-services-based method, net primary productivity method, situation space method, energetic ecological footprint model, system dynamics model, and coupling model. We compared the advantages and disadvantage of different methods and analyzed their applicable conditions. As ECC research has advanced, related studies have gradually extend to land systems, watershed systems, ecologically vulnerable areas, tourism systems, and urban comprehensive systems, which have solved relevant eco-environmental problems based on ECC assessments. Currently, ECC research lacks a standard definition for the ECC index threshold, research related to dynamic monitoring and early warning, sufficient consideration of scientific and technological drivers, and spatial pattern analyses. Future trends in ECC-related research should provide a large-scale assessment of cross-border areas and ecological vulnerable areas, construct an ecological warning platform, and consistently analyze ECC and regional leading industries.

Assessing the Health of Inland Wetland Ecosystems over Space and Time in China

Wetland is a unique natural landscape pattern,which provides a variety of important functions and services for human societies.With the rapid develop of the economy and accelerated urbanization,the inland wetlands are faced with series of problems,including reduced area,weakened wetland functions,and deterioration of the wetland ecosystem environment.Therefore,it is necessary to quantitatively assess the ecological health of China’s inland wetlands,which is key to the sustainable development of ecosystems.However,most assessments of wetland ecosystems only examine single wetlands or watershed wetlands,and there are few assessments of wetland health at the national level.In this paper,based on land cover data,climate data,and social and economic data,an assessment system of inland wetland health is established by using the Pressure-State-Effect-Response(PSER)model,which includes 15 assessment indicators.Analytic hierarchy process(AHP)was used to define the indicator weights.Then we assessed the ecosystem health of the inland wetlands of China in 2010 and 2018,which produced three main results.(1)Unlike ecosystem health evaluated by administrative districts,wetland ecosystem health(WEH)evaluation based on the grid could provide additional details of wetland health.(2)The area of inland wetlands increased by 16328 km^(2) in 2018 compared to 2010,and the average wetland ecosystem health index in 2018 was 3.45,compared to an index value of 3.24 in 2010.(3)In 2018,wetlands in the better,good,moderate and poor conditions represented about 26.3%,46.4%,26.9%and 0.5%of the total,respectively.These results provide a practical guide for protecting and managing wetland system resources and reliable information for land use planning and development.

Ecological Security Assessment of the Yancheng National Nature Reserve based on GIS

This study used remote sensing and GIS to analyze the landscape pattern changes in the Yancheng Nature Reserve from 1983 to 2018,established an evaluation index system based on the regional natural-socio-economic complex ecosystem security pattern,and then analyzed the spatial characteristics of ecological security changes and discusses reasons for these changes.The results show that the landscape pattern changed dramatically from natural landscape to a mixture of natural landscape and artificial landscape from 1983 to 2018 due to the intensification of human activities.At present,the ecological security status of the protected areas is not optimistic.From the perspective of the survival status of red-crowned cranes,the protected areas are suitable.However,due to the increase of human activities and policy adjustments,the habitat of red-crowned cranes is fragmented.The red-crowned crane currently gathers in localized areas such as the core area and the buffer zone.We should pay more attention to management,policy development and the environmental awareness of local residents.At the same time,it is necessary to reduce the intensity of human activities within the reserve.

Frequent Applications of Organic Matter to Agricultural Soil Increase Fungistasis

Soil-borne plant pathogens are among the most important limiting factors for the productivity of agro-ecosystems. Fungistasis is the natural capability of soils to inhibit the germination and growth of soil-borne fungi in the presence of optimal abiotic conditions. The objective of this study was to assess the effects of different soil managements, in terms of soil amendment types and frequency of application, on fungistasis. For this purpose, a microcosm experiment was performed by conditioning a soil with frequent applications of organic matter with contrasting biochemical quality （i. e., glucose, alfalfa straw and wheat straw）. Thereafter, the fungistasis response was assessed on four fungi （Aspergillus niger, Botrytis cinerea, Pyrenoehaeta lycopersici and Trichoderma harzianum）. Conditioned soils were characterized by measuring microbial activity （soil respiration） and functional diversity using the BIOLOG EcoPlatesTM method. Results showed that irrespective of the fungal species and amendment types, frequent applications of organic matter reduced fungistasis relief and shortened the time required for fungistasis restoration. The frequent addition of easily decomposable organic compounds enhanced soil respiration and its specific catabolic capabilities. This study demonstrated that frequent applications of organic matter affected soil fungistasis likely as a result of higher microbial activity and functional diversity.