Integrated Approaches,Multiple Scales: Snag Dynamics in Burned Versus Unburned Landscapes*

By studying landscape form and patterns, we can study processes at multiple scales and determine how collectively those processes inform us about function(s). Integrating landscape ecology from a biogeographical perspective with geographic information science (GIScience) practices offers new ways to study how landscapes change over time and space, including how they can be measured, analyzed, and modeled for management needs. This article presents methodologies and selected results of analyzing spatial patterns from field data across multiple scales by examining standing dead tree (snag) processes across wildfire‐disturbed landscapes in Arizona. Our primary motivation was to illustrate a particular type of work benefiting from the coalescing of landscape ecology and GIScience, functioning at the methodological and practical overlap of these two contributing fields. Our management goals were to (1) describe spatial patterns and characteristics of snags in pairs of burned and unburned ponderosa pine forests of Arizona in four recent (within the past ten years) wildfires, (2) document bird response to wildfires by combining landscape ecology and GIScience methods, and (3) link these patterns to snag monitoring plots and cavity‐nesting bird use to predict the probability of snag use by birds and cavity nesters based on snag characteristics (snag use model). The methods and results demonstrate how integration of landscape ecology with both GIS and GIScience improves the ways to study landscapes and land management issues, in this case offering guidelines for retention of snags that provide habitat for wildlife.     

新疆宏观生态的空间分异与变化

根据新疆环境和生态特点，将新疆划分为14个二级生态区进行了研究。结果表明，新疆荒漠与非荒漠生态景观面积大致相当，但空间分异较大。新疆北部荒漠景观占全区域的约1／3，非荒漠景观占2／3，宏观生态相对稳定；新疆东部荒漠景观占全区域的2／3以上，宏观生态十分严峻；新疆南部荒漠景观占全区域的1／2，宏观生态稳定性差。沙漠、绿洲、水体三种主要景观类型中，北疆阿尔泰山南坡、伊犁盆地及南疆叶尔羌－喀什河三角洲地区沙漠化呈降低趋势；天山北坡各段及准噶尔盆地西部，20世纪90年代以来沙漠化明显减缓；新疆东部及南部其余各地区沙漠化均呈现增强趋势。新疆水体景观的变化表现为天然和人工水体面积的消长。近50年来，新疆修建的水库和坑塘等人工水体总面积与同期天然水体缩小的面积基本相当，表明新疆水体景观再近50年来的变化主要体现为水体的空间位移。绿洲景观的变化表明，北疆地区天然绿洲与人工绿洲面积的比例已经从50年代的5：1以上下降到约1：1，南疆由6：1以上下降到3：1左右。天然绿洲的减少是绿洲生态局部劣变的标志。研究还表明，新疆宏观生态的空间分异主要受自然因素的影响，其中，区域降水量的影响最为重要。     

The political ecology of Prunus africana in Cameroon

This paper provides an analysis of some current trends in political ecology and then illustrates the intermingling of politics and ecology using a case study of the exploitation and conservation of Prunus africana in Cameroon. It argues that political ecology is still a lively field, but that some recent attempts to chart a way forward for this perspective risk shifting it away from its liminal position in relation to natural and social science by being disinclined to engage with ecological processes. The case study draws attention to the strengths and shortcomings in existing attempts to weave political and economic analysis into environmental debates over the sustainable management of this tree species, which has been incorporated into phytomedical markets in Europe. The fortunes of the tree reflect its botany and ecology as well as the trajectories of the local economy, intercontinental markets for alternative health products, the policies and practices of the Cameroonian state and the politics of international aid.     

Counting Beans: Agrobiodiversity,Indigeneity, and Agrarian Reform

In‐field conservation of locally domesticated crop varieties ameliorates agrobiodiversity losses, but the interaction among nationally regulated socioeconomic factors at the local scale tends to discourage this. Analyses of household surveys conducted in Ecuador demonstrate that state and nongovernmental institutions interact to discourage cultivation of locally domesticated varieties of beans (Phaseolus spp.). Land privatization, agricultural extension, and credit programs favor market production of introduced modern bean varieties, and locally domesticated varieties are noted for favorable nutrition, culinary, and agroecological qualities. Resolving disconnections between the market and social values for landrace beans may provide agrobiodiversity conservation opportunities.     

溢油对海洋生态系统内在价值损害的评估——以“塔斯曼海”轮溢油事故为例

作者籍以能值和生态炯分析,将海洋生态内在价值补充到溢油损害评估中,并以"塔斯曼海"轮溢油事故为例,分析了生态系统内在价值损害评估的特点。结果表明溢油生态内在价值损害大于对生态服务价值的损害,前者是后者的6.9倍;能值变化反映对资本积累的损害,生态炯更突出了溢油对初级生产力的生态系统的影响。本评价是现有溢油损害评价的补充,可为彻底、有效环境治理、生态修复提供保障,对海洋开发管理决策和公众环保意识的提高将有积极的影响。     

古果属(Archae fructus)研究进展及其时代的讨论

迄今最早的被子植物—古果属(Archaefructus)，包括“辽宁古果”和“中华古果”，以其对折状心皮在轴上螺旋状排列、雄蕊成对状着生、具单沟状花粉等特征。显示了它们在早期被子植物中的原始性。古果属茎枝细弱、叶子细而深裂、叶柄基部多膨突等特征。反映了该属的水生革本特征。根据对其生殖器官及营养器官等特征研究，推测该属很可能源于现已灭绝的、古老的种子蕨类。结合对其伴生的植物化石及相关地质、地理背景等综合分析，认为古果属及叉县组下部的时代为晚侏罗世，而并非早白垩世。     

生态经济战略是江西21世纪发展的必然抉择

根据生态经济战略的核心问题和江西省的实际情况，分析了江西实施生态经济战略的必要性与可行性，指出了江西开展生态经济建设的几个切入点。     

浅水湖泊水生植被遥感监测研究进展

在浅水湖泊中,水生植物具有净化水质、抑制藻类、提供鱼类食物和栖息环境等生态功能,同时,其过度扩张也会加速湖泊淤浅和沼泽化、引起湖泊二次污染等环境负效应.实时动态地掌握湖泊水生植被类群和种群的空间分布及其面积、生物量等指标信息,对湖泊生态修复和评估、水生植被恢复和管理等具有重要现实意义.遥感技术的大面积、实时、动态等特点...