Analysis on Vegetation Succession Model and Process under Groundwater Exploitation in Subei Lake Watershed

[Objective] The study aimed to analyze vegetation succession process under groundwater mining conditions in Subei Lake watershed. [ Method] A succession model for vegetation and burial depth of groundwater level was constructed based on field survey, and it was used to pre- dict the vegetation succession rules and process according to the changes in burial depth of groundwater level in Subei Lake watershed under groundwater exploitation. [ Result~ In Subei Lake watershed, aquatic vegetation was most closely related to burial depth of groundwater level, fol- lowed by mesophytic vegetation, while psammophilous and xerophytic vegetation did not have obvious relation with burial depth of groundwater lev- el. When burial depth of groundwater level was small, dominant plants grew well, but they grew worse or died with the increase in burial depth of groundwater level. As the groundwater level fell constantly, burial depth of groundwater level went up, and vegetation succession would occur grad- ually from aquatic vegetation to mesophytic and xerophytic vegetation, from Carex L. and Iris ensata Thunb shoaly land to Achnatherum splendens shoaly lands, from Salix psammophila shrubs to Artemisia desterorum Spreng and Caragana korshinskii shrubs, and from Populus simonii to Salix matsudana. [Condusion] The research could provide scientific references for studying the relationship between groundwater resources and ecological environment in Subei Lake basin.

The carbon fluxes in different successional stages:modelling the dynamics of tropical montane forests in South Ecuador

Background： Tropical forests play an important role in the global carbon（C） cycle.However, tropical montane forests have been studied less than tropical lowland forests, and their role in carbon storage is not well understood.Montane forests are highly endangered due to logging, land-use and climate change.Our objective was to analyse how the carbon balance changes during forest succession.Methods： In this study, we used a method to estimate local carbon balances that combined forest inventory data with process-based forest models.We utilised such a forest model to study the carbon balance of a tropical montane forest in South Ecuador, comparing two topographical slope positions（ravines and lower slopes vs upper slopes and ridges）.Results： The simulation results showed that the forest acts as a carbon sink with a maximum net ecosystem exchange（NEE） of 9.3 Mg C？（ha？yr）-1during its early successional stage（0–100 years）.In the late successional stage, the simulated NEE fluctuated around zero and had a variation of 0.77 Mg C？（ha？yr）–1.The simulated variability of the NEE was within the range of the field data.We discovered several forest attributes（e.g., basal area or the relative amount of pioneer trees） that can serve as predictors for NEE for young forest stands（0–100 years） but not for those in the late successional stage（500–1,000 years）.In case of young forest stands these correlations are high, especially between stand basal area and NEE.Conclusion： In this study, we used an Ecuadorian study site as an example of how to successfully link a forest model with forest inventory data, for estimating stem-diameter distributions, biomass and aboveground net primary productivity.To conclude, this study shows that process-based forest models can be used to investigate the carbon balance of tropical montane forests.With this model it is possible to find hidden relationships between forest attributes and forest carbon fluxes.These relationships promote a better understanding of the role of tropical montane forests in the context of global carbon cycle, which in future will become more relevant to a society under global change.

Rebirth after death: forest succession dynamics in response to climate change on Gongga Mountain, Southwest China

Global climate change is having long-term impacts on the geographic distribution of forest species. However, the response of vertical belts of mountain forests to climate change is still little known. The vertical distribution of forest vegetation(vertical vegetation belt) on Gongga Mountain in Southwest China has been monitored for 30 years. The forest alternation of the vertical vegetation belt under different climate conditions was simulated by using a mathematical model GFSM(the Gongga Forest Succession Model). Three possible Intergovernmental Panel on Climate Change(IPCC) climate scenarios(increase of air temperature and precipitation by 1.8℃/5%, 2.8℃/10% and 3.4℃/15% for B_1, A_1B and A_2 scenarios, respectively) were chosen to reflect lower, medium and higher changes of global climate. The vertical belts of mountainous vegetation will shift upward by approximately 300 m, 500 m and 600 m in the B_1, A_1B and A_2 scenarios, respectively, according to the simulated results. Thus, the alpine tree-line will move to a higher altitude. The simulation also demonstrated that, in a changing climate, the shift in the vegetation community will be a slow and extended process characterized by two main phases. During the initial phase, trees of the forest community degrade or die, owing to an inability to adapt to a warmer climate. This results in modest environment for the introduction of opportunistic species, consequently, the vegetation with new dominant tree species becomes predominant in the space vacated by the dead trees at the expense of previously dominated original trees as the succession succeed and climate change advance. Hence, the global climate change would dramatically change forest communities and tree species in mountainous regions because that the new forest community can grow only through the death of the original tree. Results indicated that climate change will cause the change of distribution and composition of forest communities on Gongga Mountain, and this change may enhance as the intensity of climate change increases. As a result, the alternation of death and rebirth would finally result in intensive landscape changes, and may strongly affect the eco-environment of mountainous regions.

An Acceptance Model of Using Mobile-Government Services(AMGS)

In recent years,the telecommunications sector is no longer limited to traditional communications,but has become the backbone for the use of data,content and digital applications by individuals,governments and companies to ensure the continuation of economic and social activity in light of social distancing and total closure inmost countries in the world.Therefore,electronic government(e-Government)andmobile government(m-Government)are the results of technological evolution and innovation.Hence,it is important to investigate the factors that influence the intention to use m-Government services among Jordan’s society.This paper proposed a new m-Government acceptance model in Jordan(AMGS);this model combines the Information System(IS)Success Factor Model and Hofstede Cultural Dimensions Theory.The study was conducted by surveying different groups of the Jordanian community.Astructured questionnaire was used to collect data from203 respondents.Multiple regression analysis has been conducted to analyze the data.The results indicate that the significant predictors of citizen intention to use m-Government services in Jordan are Information Quality,Service Quality,Uncertainty Avoidance,and Indulgence vs.restraint.While,the results also suggest that Power Distance is not a significant predictor of citizen intention to use m-Government services.

COSCO Shipping Acquisition as A Success Model for Greece-China Cooperation

On July 4th,2016,China COSCO Shipping Corporation Limited('COSCO SHIPPING'or'the Group')and the Hellenic Republic Asset Development Fund(HRADF)signed a letter in Beijing,confirming that the conditions defined in the previously signed Share Purchase Agreement(SPA)have been fulfilled.It marks a decisive achievement for COSCO SHIPPING’S

青杄林恢复演替过程中的邻体竞争效应及邻体干扰指数的改进模型

本文研究了青杄(Picea wilsonii)个体生长速度与其邻体效应之间的相互关系。结果表明乔木演替初期种山杨、白桦以及青杄自身对青杄生长的影响均为竞争关系。由以基株为中心、两米为半径圆内所有个体所测得的邻体干扰可以解释青杄生长速度变异的百分之三十以上。在本文中,我们还改进了邻体干扰指数,提出应该考虑基株自身的个体大小,由改进的指数模型能够解释青杄生长速度变异的百分之四十五左左。因此可以说改进指数要优于原先的指数。根据本文所得的结果,我们可以断定青杄林恢复演替的动力是优势植物种间的竞争。

草地退化演替过程及诊断研究进展

随着人口的不断增加和现代工农业文明的冲击,草地生态系统出现不同程度的退化,导致草地生态系统组成、结构、过程和功能等方面发生量和质的变化;对草地退化的系统理解是进行草地恢复与重建的基础与前提。本文综述了草地退化的内涵、驱动力、退化过程与特点,以及草地生态系统退化程度诊断等一系列问题,绘制了描述草地退化程度的概念模型;建议从生态学角度研究草地退化程度诊断时选择相应的气候顶级系统或受干扰程度较轻的"自然生态系统";从草地经营学角度研究草地退化程度诊断时选择适度放牧草地作为参照系统。归纳了退化草地生态系统诊断的生物途径、生境途径和功能服务途径;分析了草地退化程度诊断的方法与可选择的指标体系,并对草地退化程度诊断及草地恢复中应注意的事项进行了讨论。

沙地飞播植被演替规律初探

本文主要探讨了飞播后植被的演替规律和演替机制。采用数学方法划分了流动沙丘、固定沙丘和丘间低地植被的演替阶段,并指出:流动沙丘群落的演替动力是种群自身消长的结果;固定沙丘群落的演替动力是种间竞争的结果。建立了两种新的演替模式:恢复式和互补式。

Factors influencing online information acquisition: The case of Chinese college students

Purpose： This study intends to examine the factors that influence Chinese college students＇ use of the lnternet for acquiring information. Design/methodology/approach： This paper developed the research model by using the technology acceptance model （TAM） and information system success model as the theoretical foundation. The proposed model was empirically tested with the structural equation modeling technique based on data collected from a survey of 357 college students. Findings： The results show that 1） perceived ease of use, perceived usefulness and perceived playfulness all have a positive impact on the intention to use the Internet for acquiring information, 2） use context and system quality significantly influence perceived usefulness and perceived ease of use, and 3） service quality has a positive impact on perceived ease of use but not on perceived usefulness. Likewise information quality has no positive effect on perceived usefulness. Research limitations： The survey respondents were mainly from college students in Nanjing. We need to recruit college students in the western or other developing areas in China to further validate our findings. Practical implications： This study puts forward some feasible suggestions for university libraries to improve information organization and the use of digital library resources to better meet the needs of library users. Originality/value： This study provides insights into the understanding of the factors affecting college students＇ online information acquisition from multiple perspectives.

Designing and Evaluating a Collaborative Knowledge Management Framework for Leaf Disease Detection

Knowledge Management(KM)has become a dynamic concept for inquiry in research.The management of knowledge from multiple sources requires a systematic approach that can facilitate capturing all important aspects related to a particular discipline,several KM frameworks have been designed to serve this purpose.This research aims to propose a Collaborative Knowledge Management(CKM)Framework that bridges gaps and overcomes weaknesses in existing frameworks.The paper also validates the framework by evaluating its effectiveness for the agriculture sector of Pakistan.A software LCWU aKMS was developed which serves as a practical implementation of the concepts behind the proposed CKMF framework.LCWU aKMS served as an effective system for rice leaf disease detection and identification.It aimed to enhance CKM through knowledge sharing,lessons learned,feedback on problem resolutions,help from co-workers,collaboration,and helping communities.Data were collected from 300 rice crop farmers by questionnaires based on hypotheses.Jennex Olfman model was used to estimate the effectiveness of CKMF.Various tests were performed including frequency measures of variables,Cronbach’s alpha reliability,and Pearson’s correlation.The research provided a KMS depicting KM and collaborative features.The disease detection module was evaluated using the precision and recall method and found to be 94.16%accurate.The system could replace the work of extension agents,making it a cost and time-effective initiative for farmer betterment.

A Successful Model

A special economic zone’s three-decade economic miracle is celebrated shenzhen, a southern coastal cityin Guangdong Province, neighboring Hong Kong, has markedits 30th anniversary as China’s first economic development zone.

羊草草地放牧演替阶段的人工神经网络分析方法

本文提出羊草草地放牧演替阶段分析的人工神经网络方法，并对松嫩平原南部羊草草地进行了具体研究，其结果与野外实际调查一致。结果表明，神经网络方法性能良好，可望成为植物群落演替阶段分析的有效手段。