Fishers,Farms, and Forests in Eastern North America

The fisher (Martes pennanti) has recently recovered from historic extirpations across much of its geographic range. There are at least five explanations for the recovery of the fisher, including changes in the amount of habitat, the suitability of habitat, trapping pressure, societal attitudes toward predators, and climate. We evaluated a recovering fisher population in Ontario to test two conditions we viewed as necessary to support the hypothesis that fisher populations have increased due to an increase in the amount of forested land. First, we tested whether the amount of forested land has increased. Second, we tested whether contemporary fisher abundance (and therefore habitat quality) was related to the amount of forest. Topographic maps showed that the proportion of forested land in the study area had increased by 1.9% per decade since 1934 and 3.3% per decade since 1959, likely as a result of land conversion from agricultural uses. Overall the proportion of the study area that was forested increased from 29% to 40% during 1934 to 1995. Census data from the region indicated that there had been a decline in the amount of land area being farmed during the last 50 years. Recent livetrapping data showed that fisher abundance was positively related to the proportion of landscapes that were forested. Based on our results, we could not reject the hypothesis that an increase in the amount of forested land has contributed to the recovery of fisher populations.     

Socioeconomic Dimensions of Changes in the Agricultural Landscape of the Mediterranean Basin: A Case Study of the Abandonment of Cultivation Terraces on Nisyros Island,Greece

Agricultural landscapes illustrate the impact of human actions on physical settings, and differential human pressures cause these landscapes to change with time. Our study explored changes in the terraced landscapes of Nisyros Island, Greece, focusing on the socioeconomic aspects during two time periods using field data, cadastral research, local documents, and published literature, as well as surveys of the islanders. Population increases during the late 19^th to early 20^th centuries marked a significant escalation of terrace and dry stone wall construction, which facilitated cultivation on 58.4% of the island. By the mid-20^th century, the economic collapse of agricultural activities and consequent emigration caused the abandonment of cultivated land and traditional management practices, dramatically reducing farm and field numbers. Terrace abandonment continued in recent decades, with increased livestock grazing becoming the main land management tool; as a result, both farm and pasture sizes increased. Neglect and changing land use has led to deterioration and destruction of many terraces on the island. We discuss the socioeconomic and political backgrounds responsible for the land-use change before World War II (annexation of Nisyros Island by the Ottoman Empire, Italy, and Greece; overseas migration opportunities; and world transportation changes) and after the war (social changes in peasant societies; worldwide changes in agricultural production practices). The adverse landscape changes documented for Nisyros Island appear to be inevitable for modern Mediterranean rural societies, including those on other islands in this region. The island’s unique terraced landscapes may qualify Nisyros to become an archive or repository of old agricultural management techniques to be used by future generations and a living resource for sustainable management.     

Incentives for low-input land-use types and their influence on the attractiveness of landscapes

Changes in agricultural policy have traceable effects on landscape aesthetics. For the catchment area of Lake Greifensee, an economic land-use model predicted land-use changes caused by agricultural policy. Three scenarios implementing different direct payment schemes show that land-use intensity will decrease by 2011 compared with the ‘reference status’ 2000.The output of the economic land-use model is explicit in space. It was assessed by the ‘naturalness’ perception factor of the method proposed by Hoisl et al. [1989. Landschaftsästhetik in der Flurbereinigung. Materialien zur Flurbereinigung—Heft 17. Bayerisches Staatsministerium für Ernährung, Landwirtschaft und Forsten, München] with regard to landscape aesthetics. Even though lower land-use intensity is generally predicted by 2011, the values of the ‘naturalness’ perception factor do not significantly improve if the payment scheme remains unchanged, or if the payment scheme is amended by incentives for specific location of the ecological compensation areas (ECAs). A significant reduction in the values of the ‘naturalness’ perception factor was found when subsidies for ECA's were cancelled. This leads us to the conclusion that in order to keep Swiss landscapes as attractive as they are at present, policy must sustain incentives for low-intensity land-use types.     

金坛区景观格局时空变化及驱动力分析

基于2010—2015年江苏省常州市金坛区高分辨率遥感影像,综合分析了生态系统空间分布格局及其演变特征,初步揭示了生态系统的驱动力及其对生态系统格局变化的影响。结果表明,金坛区生态系统类型主要由农田、湿地、城镇构成,3者合占总面积的87. 8%; 2010年以来,金坛加快实施城市"东扩南移"战略,原有农田不断被蚕食,生态系统的聚集度、边界密度有所上升,城镇更加连片分布,城镇面积已接近2020年18 604. 7 hm~2的建设红线。     

原生态环境景观设计在城市公园的应用

人类文明的发展,不断地在改变地球的生态环境,我们赖以生存的环境正在逐渐恶化,在城市中生活的人们远离了自然,生活环境已经不再健康,雾霾、水污染以及绿化的减少,都严重影响着人类自身的发展。在意识到环境对人类社会发展的重要性之后,人们开始重视城市环境的改造,引入原生态环境景观,希望获得人类与自然的和谐与平衡,在这样的背景下城市公园的概念受到了广泛的关注,城市公园的景观设计开始追求原生态,综合考虑了对原生态环境的保护和利用,不断完善城市公园的设计,发挥原有自然环境的作用,让人工设计与自然天成融为一体,打造城市中心的绿肺,改善城市生态环境,维护人类社会生产生活与自然环境的平衡,为人类建设更为宜居的生活环境。     

Land cover and land use changes in a Brazilian Cerrado landscape: drivers,processes, and patterns

The Cerrado is one of the most threatened biomes in South America. To create protection actions on any scale, understanding drivers and consequences of land cover and land use (LC and LU) is essential. This study defines the composition and configuration of a Cerrado landscape watershed from 1975 to 2011. Using Landsat images and socioeconomic census data, we determined the forces acting on LC and LU change processes and their consequences. LC classes differ from LU classes for landscape dominance and processes. Economic opportunities drove LU change and its spatial distribution was related to soil, streams, and roads. Deforestation was the main cause of forest loss but forest degradation was also important, with both presenting different patterns. The spatial distribution of bare soil was related to pasture in degradation and streams. Bare soil distribution was related to pasture in degradation and streams. We concluded that broad scale factors drove changes, but local features determined distribution, and that watershed conservation plans should act on different scales, with management being spatially explicit.     

人工浮岛对城市景观用水水质净化效果的研究

为了研究浮岛对城市景观用水的水质净化效果,用美人蕉制作了人工浮岛,分别在大连市某小区户外水塘和实验室内进行了实验。对其水样进行化验、观察、分析和研究。结果表明:人工植物浮岛对水质净化有明显的效果,在室内对总氮、总磷和COD的去除率分别为91.35%、45.46%和56.49%;在户外对总氮、总磷和COD的去除率分别为60%、84.33%和24.25%。实验证明了人工浮岛在城市景观用水处理中有广阔的应用前景。     

Simulating the potential for ecological restoration of dryland forests in Mexico under different disturbance regimes

Examining the potential for ecological restoration is important in areas where anthropogenic disturbance has degraded forest landscapes. However, the conditions under which restoration of degraded tropical dry forests (TDF) might be achieved in practice have not been determined in detail. In this study, we used LANDIS-II, a spatially explicit model of forest dynamics, to assess the potential for passive restoration of TDF through natural regeneration. The model was applied to two Mexican landscapes under six different disturbance regimes, focusing on the impact of fire and cattle grazing on forest cover, structure and composition. Model results identified two main findings. First, tropical dry forests are more resilient to anthropogenic disturbance than expected. Results suggested that under both a scenario of small, infrequent fires and a scenario of large, frequent fires, forest area can increase relatively rapidly. However, forest structure and composition differed markedly between these scenarios. After 400 years, the landscape becomes increasingly occupied by relatively shade-tolerant species under small, infrequent fires, but only species with both relatively high shade tolerance and high fire tolerance can thrive under conditions with large, frequent fires. Second, we demonstrated that different forms of disturbance can interact in unexpected ways. Our projections revealed that when grazing acts in combination with fire, forest cover, structure and composition vary dramatically depending on the frequency and extent of the fires. Results indicated that grazing and fire have a synergistic effect causing a reduction in forest cover greater than the sum of their individual effects. This suggests that passive landscape-scale restoration of TDF is achievable in both Mexican study areas only if grazing is reduced, and fires are carefully managed to reduce their frequency and intensity.     

A hybrid scheme for comparing the effects of bird diversity conservation approaches on landscape patterns and biodiversity in the Shangan sub-watershed in Taiwan

This work utilizes bird survey data, regression modeling, land-use modeling and landscape metrics to evaluate the effects of various spatial bird diversity conservation approaches on land-use allocation, land-use patterns, and biodiversity in the Shangan sub-watershed in central Taiwan. A survey of the distribution of species revealed that bird species are concentrated in the central and western parts of the sub-watershed. The results obtained using a Shannon-Weaver diversity regression model suggest that diversity of land-use increases the diversity of bird species. Logistic regression results verify that socio-economic factors determine the potential advantages of designating a particular type of land-use in certain parts of the study area. The results of land-use simulation modeling indicate that the eastern and southwestern areas of the sub-watershed will change most frequently between 2007 and 2017. Additionally, increasing the areas to protect bird diversity will effectively increase the patch size, habitat core area, edge effect and habitat connectivity. The Shannon-Weaver diversity regression model shows that protecting bird species diversity in large areas increases bird diversity. The proposed modeling approach is an effective tool that provides useful information for ecological planning and policymaking related to watersheds.     

基于集对云的机坪运行管理移交安全评价研究*

为对航空器机坪运行管理移交下运行安全状况做出科学合理的评价,结合具体机场的机坪运行复杂性,首先引入PSR模型,从压力、状态和响应3个方面构建管理移交机场机坪运行安全评价指标体系;随后使用熵值法进行指标权重计算,并运用欧几里得度量函数进行组合赋权;接着引入集对理论和云模型,结合组合权重使用正向云发生器确定综合云联系度,利用Python绘制等级云图,评判系统安全等级;最后以某大型机场为例进行验证。研究结果表明:本文所提出的机坪运行管理移交安全评估评价方法经验证与实际运行情况相符,能够为机坪运行安全评价提供理论参考。