Forest fragmentation and duration of forest tent caterpillar (Malacosoma disstria Hübner) outbreaks in northern hardwood forests

In northern forests dominated by aspen (Populus spp.), the duration of outbreaks of forest tent caterpillar (Malacosoma disstria Hübner) has been reported to increase with forest fragmentation. This relationship has not been tested in other forest types affected by this widespread native defoliator. From 2002 to 2007, a large-scale outbreak of this insect in the northeastern United States defoliated millions of hectares, with sugar maple (Acer saccharum Marsh.) the primary host. We used digital defoliation maps generated from aerial surveys and national land cover data to assess the effect of fragmentation on outbreak duration in areas of NY, MA, VT, and NH. We found that outbreak duration increased with forest cover and decreased with the forest edge, in opposition to the pattern previously reported for aspen-dominated forests in Canada. This pattern was significant from plot sizes ranging from 100 m to 1000 m in radius. The relationship between FTC and its natural enemies, which was postulated to underlie the effect of fragmentation on outbreaks in aspen forests, may be affected differently in northern hardwood forests, or other factors may be more important in determining outbreak duration in this forest type.     

生物多样性,生态系统功能与时空尺度

生物多样性与生态系统功能的关系已成为重大的科学问题呈现在生态学界。大量的研究表明, 生物多样性对系统生产力、分解性、养分循环以及稳定性等多种功能均有重要影响。本研究在众多研究的基础上, 就生物多样性的基本内容——物种多样性对生态系统功能的2个方面,即生产力和入侵性的关系模式、作用机理、存在的争议, 以及时空尺度对其的影响作一综述。通过生物多样性与生态系统功能关系基本理论的探讨, 阐明生物多样性对生态系统功能的重要影响及潜在机理, 以期为相关研究者提供科学参考, 以促进我国的生物多样性研究。     

鹰眼的扩展及其在制图方面的应用

通过对传统鹰眼的概念和功能进行扩展,发掘了鹰眼在制图方面的应用潜力。以主视图全图、主视图客户区、鹰眼指示框和鹰眼范围框架的获取为核心,运用图形仿射变换的基本原理和算法与ArcEngine提供的地图展示功能相结合的方法来实现多种鹰眼功能。在对鹰眼的实现方法进行分类和总结的基础上,得出普通鹰眼与放大镜窗口的实现原理相同,且鹰眼的定位功能是拖动功能和拉框功能实现的基础。该鹰眼在辅助矿业开发秩序遥感调查制图中取得了良好的应用效果。     

缺水城市的人口和用地规模定量评价

根据城市可持续发展和经济、环境、社会综合效益最大化原则,提出了可大致刻画城市人口和用地规模与经济、环境、社会相互关系的数学模型,并找到了一个评价当前缺水城市人口和用地规模是否满足经济、环境、社会均具有较强可持续发展性要求的指标。     

百合鳞叶DNA提取及RAPD分析

以百合新鲜鳞叶为材料,利用RAPD分子标记对来自我国5省共16份百合样品进行了分析。结果表明:采用改良CTAB法提取百合鳞叶中DNA条带清晰较,且从120条随机引物中筛选出35条有效引物,共得到769个扩增位点,其中628个位点具有多态性,占81.7%。聚类分析表明,16个百合材料在阈值为0.940 7时分为2个RAPD群,即分别属于百合科的百合属和大百合属;阈值为0.579 0时,百合属分为3个种,即分别为百合、卷丹和细叶百合。这些均可为进一步研究百合的分子生物学特性打下基础,为鉴定中药材百合品种品系的新方法提供充分的实验依据。     

Analysis of potential impacts of climate change on forests of the United States Pacific Northwest

As global climate changes over the next century, forest productivity is expected to change as well. Using PRISM climate and productivity data measured on a grid of 3356 plots, we developed a simultaneous autoregressive (SAR) model to estimate the impacts of climate change on potential productivity of Pacific Northwest (PNW) forests of the United States. Productivity, measured by projected potential mean annual increment (PMAI) at culmination, is explained by the interaction of annual temperature, precipitation, and precipitation in excess of evapotranspiration through the growing season. By utilizing information regarding spatial error in the SAR model, the resulting spatial bias is reduced thereby improving the accuracy of the resulting maps. The model, coupled with climate change output from four generalized circulation models, was used to predict the productivity impacts of four different scenarios derived from the fourth IPCC special report on emissions, representing different future economic and environmental states of the world, viz., scenario A1B, A2, B1 (low growth, high economic development and low energy usage), and COMMIT. In these scenarios, regional average temperature is expected to increase from 0.5 to 4.5 °C, while precipitation shows no clear trend over time. For the west and east side of the Cascade Mountains, respectively, PMAI increases: 7% and 20% under A1B scenario; 8% and 23% under scenario A2; 5% and 15% under scenario B1, and 2% and 5% under the COMMIT scenario. These projections should be viewed as potential changes in productivity, since they do not reflect the mitigating effects of any shifts in management or public policy. For managers and policy makers, the results suggest the relative magnitude of effects and the potential variability of impacts across a range of climate scenarios.     

Dynamics of mangrove forests in the Mangoky River delta,Madagascar, under the influence of natural and human factors

Mangroves in Madagascar cover 327 000 ha to 340 300 ha. Several authors have studied these mangroves, but we do not yet have a complete knowledge of these ecosystems. The present study is an attempt to respond to this concern by analyzing dynamics and changes in the extent of the mangrove forest in the Mangoky delta (SW Madagascar) between 1951 and 2000. The comparison between base maps and Landsat TM images shows that the mangrove area remained relatively stable, even increasing slightly (+189 ha) between 1951 and 1979. From 1979 to 1994, its area decreased from 21 426 ha to 11 706 ha (−9720 ha). It then increased again (+84 ha) between 1994 and 2000. The balance was a decrease of 41.74% between 1951 and 2000. These figures may be compared with national (−15% in 56 years) and world (−35% for the last 20 years) statistics. Three main reasons are given to explain these changes: (1) the hydrological and sedimentological behavior of the Mangoky River; (2) the mechanism of plant succession, which depends on tides and on the characteristics of the substratum and (3) human activities and logging, which have increased since the 1980s in the Mangoky delta.     

Greening the blue revolution of small‐scale freshwater aquaculture in Mymensingh,Bangladesh

Rapid development of small‐scale freshwater aquaculture in the Mymensingh district of north‐central Bangladesh has been linked to a ‘blue revolution’. Mymensingh is ranked first among districts of pond fish production in Bangladesh. Aquaculture in Mymensingh plays an important role in the local economy, contributing to food production, livelihood opportunities, income generation, poverty alleviation and social transformation. However, a number of challenges, particularly social, economic and environmental issues, will need to be overcome to translate its benefits effectively. We propose a conceptual framework for greening the blue revolution of aquaculture, which links social, economic and ecological aspects for promoting the importance of socio‐ecological, ecological‐economic and socio‐economic interactions. We conclude that active community participation, institutional collaboration and policy support are needed for greening the blue revolution of aquaculture in Mymensingh.     

2013年延河流域特大暴雨下的滑坡特征

2013年延河流域遭遇了有气象记录以来的强降雨,引发了大范围的滑坡。依据中国地质调查局《滑坡崩塌泥石流灾害详细调查规范》（DD2008—02）,对延河流域从南到北6个典型小流域内发生的滑坡进行调查。结果表明:（1）2013年延河流域大雨、暴雨主要集中在7月,其中宝塔区7月侵蚀性降雨量最大（766.8 mm）,是延河流域2013年暴雨的暴雨中心区;（2）距离暴雨中心最近的南部2个小流域的滑坡侵蚀模数最大,达7 000 t/km²,中部2个小流域为3 700 t/km²,北部的为1 400 t/km²左右,滑坡量与滑坡频率也呈现南部 > 中部 > 北部的规律;2013年暴雨引发的滑坡为浅表层滑坡,属于黄土内滑坡,分布在20°～60°的斜坡上;滑坡均为小型滑坡,其中规模≤1 000 m³的滑坡最多,占总调查滑坡数量的78%, > 5 000 m³的滑坡很少。