An agent based model to simulate structural and land use changes in agricultural systems of the argentine pampas

The Argentine Pampas, one of the main agricultural areas in the world, recently has undergone significant changes in land use and structural characteristics of agricultural production systems. Concerns about the environmental and societal impacts of the changes motivated development of an agent-based model (ABM) to gain insight on processes underlying recent observed patterns. The model is described following a standard protocol (ODD). Results are discussed for an initial set of simplified simulations performed to understand the processes that generated and magnified the changes in the Pampas. Changes in the structure of agricultural production and land tenure seem to be driven by differences among farmers’ ability to generate sufficient agricultural income to remain in business. In turn, as no off-farm or credit is modeled, economic sustainability is tied to initial resource endowment (area cropped). Farmers operating small areas are economically unviable and must lease out their farms to farmers operating larger areas. This leads to two patterns: (a) a concentration of production (fewer farmers operating larger areas) and, (b) an increase in the area operated by tenants. The simulations showed an increase of soybean area, linked to the higher profitability of this crop. Despite the stylized nature of initial simulations, all emerging patterns are highly consistent with changes observed in the Pampas.     

Projecting landscape changes in southern Chile: Simulation of human and natural processes driving land transformation

We describe a simulation model representing the most important human and natural factors driving land use and cover changes (LUCC) in southern Chile. We evaluate the model by examining its ability to simulate LUCC observed over the past three decades, conduct a sensitivity analysis of simulated trends to changes in important model parameters, and use the model to project likely landscape transformations over the next decade under “as usual,” “pessimistic,” and four “optimistic” scenarios. The model consists of five submodels representing LUCC on two distinct soil formations (volcanic ash and gleysols) and four major land use categories: native forest, agricultural land, shrubland, and urban land. Land use and cover sub-categories include old growth forests, secondary forests, and low and flooded shrubland. The model simulated well general historic trends in forest cover, agricultural land, shrubland, and urban land: from a forest-dominated landscape in 1976 to a landscape dominated by shrubland and agricultural land by 2007. Forest loss, forest degradation by logging and clearing for agriculture were the most important direct drivers of LUCC: forest logging and clearing were most important from 1976 to 1985, whereas after 1985 logging for firewood, driven by population growth, was most important. Sensitivity analysis indicated that model projections of general trends in the main land use and cover categories were not overly sensitive to changes in important model parameters, although further study is necessary to improve our estimates of the proportion of pasture requirements supplied by clearing low shrubland. Projections of LUCC suggested that a reduced amount of secondary forest would be left by 2017 if no actions are taken to reduce forest loss (“as usual”). Increasing population (“pessimistic scenario”) resulted in similar trajectories than those predicted by the as usual scenario, whereas reducing logging for firewood and increasing forest recruitment from shrubland could reduce loss of native forest by nearly one-third (“optimistic scenarios”). Surprisingly, shrubland exhibited the most complex and influential dynamics in all scenarios, being the immediate outcome of forest loss and the main long-term source of land for agriculture, urban expansion, and forest recovery. Few studies in Chile, or elsewhere, have considered the importance of this intermediate successional stage. Of the scenarios simulated, financial incentives targeted toward channeling shrubland into regenerated forest seemed most promising, although obstacles to such a management strategy exist.     

Maintaining land use agreements in Papua New Guinea Mining: ‘Business as usual’?

Most large scale resource extraction projects in Papua New Guinea (PNG) require companies to negotiate with customary landowners for access to development sites. In the discussion of process and challenges of development and operation of projects, particularly mines, the paper, basing as a case study of land use arrangements in PNG mining, has several objectives to address. First, it discusses land use arrangements in the mining industry and how they have evolved over the last few decades. Today, most of these arrangements involve pluralistic framework agreements which have been shaped by land tenure debates, civil uprisings, government initiatives and increasingly politically savvy customary landowners. This pluralistic process encourages key stakeholder involvement, particularly customary landowner participation which has been an innovative piece of sustainable mineral policy development in PNG. Second, the paper argues that ‘it is not business as usual’ for mining companies as it would generally be the case in developed and many developing countries because they are increasingly forced to be proactive in addressing landowner and community interests while managing mining projects. A brief overview of land use debates in PNG is summarised at the outset to provide background to mining and development in the country. Third, the significance of the corporate social responsibility (CSR) paradigm and its impact on business, particularly the mining industry is acknowledged intermittently in the discussion to shed light on how it is influencing development of local communities. Finally, the paper argues that the post-Bougainville period has led to a change of the old enclave model of mining development to a broad based community driven form of development around mining. However, it is difficult to predict as to how this model of mining led development in rural PNG will span out in the long run. In the meantime, genuine landowner partnerships with developers and government in the management and operation of mining projects in the country are proving to be a positive outcome for everyone despite some major challenges.     

Effects of veterinary fences on Wildlife conservation in Zimbabwe

In Zimbabwe, veterinary fences are used to control trypanosomiasis and foot- and-mouth disease, two important diseases that threaten cattle production and beef exports. Wildlife is implicated in both instances and the effects of fences on wildlife conservation and land use are discussed in relation to these two diseases. Advantages and disadvantages related to direct and indirect fence effects are outlined. Although the maintenance of fences for trypanosomiasis control is likely to become obsolete, control of foot- and-mouth disease will rely on fences for the foreseeable future. Most of Zimbabwe's protected wildlife areas are located in marginal agricultural land around the periphery of the country where cattle productivity is low. This land should be excluded from any involvement in the beef export industry rather than attempting its inclusion through cordoning and isolating individual protected areas. Within such land, the need for rigid veterinary restrictions should then disappear and allow more flexible strategies for disease control, including adaptive and imaginative approaches to land-use planning.     

Land cover change and abrupt environmental impacts on Javan volcanoes, Indonesia: a long-term perspective on recent events

Based on a presentation of the spectacularly abrupt environmental and societal processes occurring on Java since the 1990s, and using that as an analogue to compare their consequences with the known environmental history of the island, we unravel the relative contributions of natural and human impacts in shaping the environment of Java. Our work is based on remote sensing, Geographical Information System analysis, field-based observations and measurements of responses to abrupt land cover changes in the last 10 years. Ecological disturbance has been endemic to the long-term history of Java, but montane forests on volcanoes have since ca. 1990 become the last frontier of colonisation and are for the first time rapidly receding. We reveal how human disturbance of natural ecosystems, today as in the past, tends to be the greatest where resistance is the least. This appears true within the regional setting of Southeast Asia, where Javan forests since the last glaciation have constituted a biogeographical ecotone with a limited natural ability to regenerate after some imbalance. It is equally true at the scale of single events where humans will turn a natural disturbance to their own advantage. Overall, it remains difficult to deconvolve the signals of spontaneous human impacts and of localised natural events such as volcanic activity, El Niño-related forest fires or longer climatic anomalies because humans are opportunistic in their attitudes to natural variability and so the two are often inextricably linked. The clearest impact on land cover and land degradation comes from the history of state-organised deforestation, whether colonial or indigenous, because its impact has been systematic, pervasive and regionally consistent. Javan environments have shown astonishing signs of resilience under the abrupt, cumulative impacts that have been inflicted over the last four centuries in successive iterations, possibly because the high-energy tropical and volcanic environment is a system in which sediment turnover is naturally rapid and where past scars of land degradation either heal rapidly or are soon destroyed by younger events. However, the volcanoes are the island’s keystone reservoirs of water, sediment and biodiversity and command the geomorphic metabolism of the lowlands. By removing forests from increasingly crowded mountain slopes, Javanese society is following a trajectory in which new nonlinear responses to environmental hazards and change may limit our capacity to anticipate and contain environmental risk to human life and property.     

交通建设环评中生物量影响评价指标探讨

随着公路铁路等交通项目的建设,其面临的生态环境压力日益增大,周边地区生物量发生很大变化。本文针对交通建设活动对生物量的影响问题,研究提出一种基于土地利用类型变化的交通建设项目前后生物量变化的评价指标和评价标准,并采用京沪铁路电气化北京-济南段实际工程建设进行实例应用。     

基于生态绿当量的开封土地利用研究

基于生态绿当量的提出与模型的建立,计算水田、旱田、园地和林地的生态绿当量,得到研究区域的综合绿当量,并将该值与以最佳森林覆盖率的生态优化标准进行比较。对研究区域的土地利用结构进行现状评价,在此基础上对研究区域土地利用结构进行优化调整。以开封为例,针对开封土地利用问题,提出优化方案,以期达到经济、社会和生态效益的统一。     

像素法计算土地复垦方案非矢量化土地利用现状图斑面积

土地复垦方案编制过程中,需计算各地类面积,搜集的资料如果仅有非矢量化线条版土地剩用现状图,如纸版或Jpg、Tif等图像文件,统计各地类图斑块面积手工描图工作量比较大,且精确度不能满足方案需要,常常成为土地复垦方案编制效率提高的制约因素。笔者根据多年从事计算机技术及工程绘图经验,总结并实践了利用像素点法计算不规则形状图斑面积的方法,供环评、土地复垦工作者参考。     

Method to map human and infrastructure vulnerability using CNN land cover: Case study of floating tank explosion at petrochemical plants of LaemChabang,Thailand

Industrial storage tanks, used to store flammable materials in the petrochemical industry, can induce potential fire and explosion under specific conditions. Therefore, it is necessary to map the population and environment vulnerability, and, to develop procedures for emergency responses in order to reduce potential casualties. In order to achieve this, Convolutional Neural Networks (CNN) are used in this study using 6 classes: floating tank, forest, house, road, wasteland and water. Datasets are built for a total of approximately 1.4 million tiles with a resolution of 0.33m/pixel and their size are optimized in function of the class. The 6 associated CNN models are built and optimized to classify each class. The validation of the models shows that, with the exception of road and wasteland where the precision is only 73% and 89% respectively, the other 4 classes have a value higher than 95%. Post-processing is performed on each prediction before aggregating these results to obtain the land cover. For the floating tank class, a 5 step post-processing is used based on a Density-Based Spatial Clustering of Applications with Noise algorithm (DBCAN) after which blast simulation is applied and effects on people, buildings and trees are obtained through 4 steps. Finally, the petrochemical site of LaemChabang in Thailand is used as study case. Except for the road class that is difficult to detect, land cover is well performed. Human casualties and surface of damaged buildings are finally estimated demonstrating the usefulness of the tool to be used for the emergency planning of industrial disasters.