蚊虫地理生态位及其重叠群划分的初步研究

本文将物种在地理上的分布范围作为地理生态位（ｇｅｏｇｒａｐｈｉｃａｌｎｉｃｈｅ）提出,并对我国蚊虫的地理生态位进行了研究。内容包括：蚊虫地理生态位宽度、地理生态位重叠指数的测定和９种蚊虫重叠群的划分。     

Measures of giant panda habitat selection across multiple spatial scales for species conservation

Examining ecological processes across spatial scales is crucial as animals select and use resources at different scales. We carried out field surveys in September 2005, March–September 2006, and April 2007, and used ecological niche factor analysis to determine habitat preferences for the giant panda (Ailuropoda melanoleuca) across 4 spatial scales: daily movement, core range, home range, and seasonal elevational migration. We found that giant pandas prefer conifer forest and mixed forest at higher than average elevation (2,157 m) of study area in the 4 scale models. However, we also observed significant scale differences in habitat selection. The strength of habitat preference increased with scale for the 2 disturbed forests (sparse forest and fragmented forest), and decreased with scale for 0–30° gentle slope and south- and north-facing aspect. Furthermore, habitat suitability patterns were scale-dependent. These findings highlight the need to determine species–environment associations across multiple scales for habitat management and species conservation. © 2012 The Wildlife Society.     

生态位模型的理论基础、发展方向与挑战

生态位模型是一个以生态位理论为基础的新兴研究领域.它通过采集研究对象的已知分布点及其相关的环境数据组成训练样本,利用数理统计或机器学习理论分析数据,构建特征函数表示物种在生态位空间的实际生态位.以生态位模型预测物种潜在分布地或计算物种间的生态位重叠等研究,在生态学、生物地理学和进化生物学研究中显得越来越重要.本文从生态位概念出发,详细解析了生态位模型的理论基础、相关的焦点争论、使用时的注意点以及可能的发展方向与面临的挑战,指出模型中要考虑人类活动对物种生态位的影响.希望本文所探讨的本领域最新的争论焦点能引起相关学者的关注与深入思考.     

Scale‐dependent effects of neighborhood biodiversity on individual tree productivity in a coniferous and broad‐leaved mixed forest in China

The relationship between biodiversity and productivity has stimulated an increasing body of research over the past decades, and this topic still occupies a central place in ecology. While most studies have focused on biomass production in quadrats or plots, few have investigated the scale‐dependent relationship from an individual plant perspective. We present an analysis of the effects of biodiversity (species diversity and functional diversity) on individual tree growth with a data set of 16,060 growth records from a 30‐ha temperate forest plot using spatially explicit individual tree‐based methods. A significant relationship between species diversity and tree growth was found at the individual tree level in our study. The magnitude and direction of biodiversity effects varies with the spatial scale. We found positive effects of species diversity on tree growth at scales exceeding 9 m. Individual tree growth rates increased when there was a greater diversity of species in the neighborhood of the focal tree, which provides evidence of a niche complementarity effect. At small scales (3–5 m), species diversity had negative effects on tree growth, suggesting that competition is more prevalent than complementarity or facilitation in these close neighborhoods. The results also revealed many confounding factors which influence tree growth, such as elevation and available sun light. We conclude that the use of individual tree‐based methods may lead to a better understanding of the biodiversity‐productivity relationship in forest communities.     

Ecological niche modeling of the sympatric giant and red pandas on a mountain-range scale

Habitat use and separation between the two sympatric species, the giant panda and the red panda, have been primary causes of coexistence at the fine scale. In this paper, we addressed the question of coexistence between species in space. By Ecological Niche Factor Analysis, we calculated species-specific habitat requirements, built habitat suitability maps and examined interspecific differences in spatial niche parameters. According to the ENFA scores, suitable habitats in the giant and red panda are surrounded by high-altitude, and are rich in conifer forest. Compared with the giant panda, however, the red panda rather preferred sparse forests, and normally colonized far from village and road. Despite similar narrow niche breadth for both pandas, difference of niche overlap indices implied that the width of environmental niche of red pandas almost completely encompasses that of the giant panda. We, therefore, suggest that differences in use of ecological niche variables may contribute to coexistence of the sympatric species in space. Based on highly suitable locations of the sympatric species maps, most official reserves appear to be poorly located or are too small, and new reserves are recommended to be established in the central part of core habitats in the Liangshan Mountains.     

The mathematical influence on global patterns of biodiversity

Although we understand how species evolve, we do not appreciate how this process has filled an empty world to create current patterns of biodiversity. Here, we conduct a numerical experiment to determine why biodiversity varies spatially on our planet. We show that spatial patterns of biodiversity are mathematically constrained and arise from the interaction between the species’ ecological niches and environmental variability that propagates to the community level. Our results allow us to explain key biological observations such as (a) latitudinal biodiversity gradients (LBGs) and especially why oceanic LBGs primarily peak at midlatitudes while terrestrial LBGs generally exhibit a maximum at the equator, (b) the greater biodiversity on land even though life first evolved in the sea, (c) the greater species richness at the seabed than at the sea surface, and (d) the higher neritic (i.e., species occurring in areas with a bathymetry lower than 200 m) than oceanic (i.e., species occurring in areas with a bathymetry higher than 200 m) biodiversity. Our results suggest that a mathematical constraint originating from a fundamental ecological interaction, that is, the niche–environment interaction, fixes the number of species that can establish regionally by speciation or migration.     

Ecological niche conservatism: a time‐structured review of evidence

Aim To evaluate the evolutionary conservatism of coarse‐resolution Grinnellian (or scenopoetic) ecological niches. Location Global. Methods I review a broad swathe of literature relevant to the topic of niche conservatism or differentiation, and illustrate some of the resulting insights with examplar analyses. Results Ecological niche characteristics are highly conserved over short‐to‐moderate time spans (i.e. from individual life spans up to tens or hundreds of thousands of years); little or no ecological niche differentiation is discernible as part of the processes of invasion or speciation. Main conclusions Although niche conservatism is widespread, many methodological complications obscure this point. In particular, niche models are frequently over‐interpreted: too often, they are based on limited occurrence data in high‐dimensional environmental spaces, and cannot be interpreted robustly to indicate niche differentiation.     

浙江省城市生态位尺度效应

作为社会复合生态系统的重要理论,城市生态位一直是研究重点,但缺少尺度效应的深入观察。以浙江省为例,首次将地市-区县-乡镇三个尺度进行横向对比,构建了多个尺度适用的城市生态位评价模型。研究通过生态位宽度、生态位重叠度、生态位分异指数和引力模型方法,对825个乡镇,71个区县和11个地市的3个尺度的生态位进行了探讨。研究结果表明:从生态位宽度来看,浙江省的生态位发展不均衡,地市尺度呈现反"C"结构,衢州市和丽水市生态位宽度最小,杭州市、湖州市和宁波市生态位宽度最大。且研究尺度越大、生态位宽度越大,则尺度效应作用越大。从生态位分异程度来看,随着尺度的缩小,分异程度逐渐增大,其中社会生态位分异程度最大。表明尺度效应在发展越不平衡的生态位维度中作用力越大。从生态位重叠度和引力模型来看,生态位宽度小的区域往往面临竞争难以摆脱困境,而生态位宽度大的区域更容易将竞争转化为合作。出现强者越强,弱者越弱的两极分化现象,丽水市和衢州市竞争最激烈而杭州市和宁波市合作更为便利。浙江省各地市可以通过资源再造、协同发展和借力帮扶策略优化区域发展。     

Endothelial and cancer cells interact with mesenchymal stem cells via both microparticles and secreted factors

Tightly associated with blood vessels in their perivascular niche, human mesenchymal stem cells (MSCs) closely interact with endothelial cells (ECs). MSCs also home to tumours and interact with cancer cells (CCs). Microparticles (MPs) are cell‐derived vesicles released into the extracellular environment along with secreted factors. MPs are capable of intercellular signalling and, as biomolecular shuttles, transfer proteins and RNA from one cell to another. Here, we characterize interactions among ECs, CCs and MSCs via MPs and secreted factors in vitro. MPs and non‐MP secreted factors (Sup) were isolated from serum‐free medium conditioned by human microvascular ECs (HMEC‐1) or by the CC line HT1080. Fluorescently labelled MPs were prepared from cells treated with membrane dyes, and cytosolic GFP‐containing MPs were isolated from cells transduced with CMV‐GFP lentivirus. MSCs were treated with MPs, Sup, or vehicle controls, and analysed for MP uptake, proliferation, migration, activation of intracellular signalling pathways and cytokine release. Fluorescently labelled MPs fused with MSCs, transferring the fluorescent dyes to the MSC surface. GFP was transferred to and retained in MSCs incubated with GFP‐MPs, but not free GFP. Thus, only MP‐associated cellular proteins were taken up and retained by MSCs, suggesting that MP biomolecules, but not secreted factors, are shuttled to MSCs. MP and Sup treatment significantly increased MSC proliferation, migration, and MMP‐1, MMP‐3, CCL‐2/MCP‐1 and IL‐6 secretion compared with vehicle controls. MSCs treated with Sup and MPs also exhibited activated NF‐κB signalling. Taken together, these results suggest that MPs act to regulate MSC functions through several mechanisms.     

Three‐dimensional cell culture model utilization in cancer stem cell research

Three‐dimensional (3D) cell culture models are becoming increasingly popular in contemporary cancer research and drug resistance studies. Recently, scientists have begun incorporating cancer stem cells (CSCs) into 3D models and modifying culture components in order to mimic in vivo conditions better. Currently, the global cell culture market is primarily focused on either 3D cancer cell cultures or stem cell cultures, with less focus on CSCs. This is evident in the low product availability officially indicated for 3D CSC model research. This review discusses the currently available commercial products for CSC 3D culture model research. Additionally, we discuss different culture media and components that result in higher levels of stem cell subpopulations while better recreating the tumor microenvironment. In summary, although progress has been made applying 3D technology to CSC research, this technology could be further utilized and a greater number of 3D kits dedicated specifically to CSCs should be implemented.     

Effect of historical land‐use and climate change on tree‐climate relationships in the upper Midwestern United States

Contemporary forest inventory data are widely used to understand environmental controls on tree species distributions and to construct models to project forest responses to climate change, but the stability and representativeness of contemporary tree‐climate relationships are poorly understood. We show that tree‐climate relationships for 15 tree genera in the upper Midwestern US have significantly altered over the last two centuries due to historical land‐use and climate change. Realised niches have shifted towards higher minimum temperatures and higher rainfall. A new attribution method implicates both historical climate change and land‐use in these shifts, with the relative importance varying among genera and climate variables. Most climate/land‐use interactions are compounding, in which historical land‐use reinforces shifts in species‐climate relationships toward wetter distributions, or confounding, in which land‐use complicates shifts towards warmer distributions. Compounding interactions imply that contemporary‐based models of species distributions may underestimate species resilience to climate change.     

En route to economical eco‐friendly solvent system in enhancing sustainable recovery of poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) copolymer

Separation of poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) [P(3HB‐co‐4HB)] from bacterial cell matter is a critical step in the downstream process with respect to material quality and eco‐balance as P(3HB‐co‐4HB) is widely used for biomedical applications. Therefore, an efficient and eco‐based extraction of P(3HB‐co‐4HB) using a combination of NaOH and Lysol in digesting the non‐polymeric cell material (NPCM) digestion is developed. The NaOH and Lysol show synergistic influence on the copolymer extraction at a high purity and recovery of 97 and 98 wt% respectively. The optimized cell digestion method was found applicable to a vast batch of cells containing copolymers from various 4HB monomer compositions. At the largest extraction volume of 100 L, P(3HB‐co‐4HB) with a purity of 89 wt% was extracted with a maximum recovery of 90 wt%. The method developed has also eliminated the cell pretreatment step. The extraction method developed in this research has not only produced an economic and efficient copolymer recovery but has also retained the copolymer quality, in term of its molecular weight and thermal properties. It demonstrates a practical and promising downstream processing method in recovering the copolymer effectively from the bacterial biomass.     

生态学中的尺度问题：内涵与分析方法

尺度问题已成为现代生态学的核心问题之一.尺度问题主要涉及3个方面：尺度概念、尺度分析和尺度推绎.主要评述前两个方面.生态学尺度有三重概念：维数、种类和组分,其中每重概念又包含了多个定义,有必要进行澄清、分类和统一.尺度分析涉及尺度效应分析和多尺度空间格局分析.格局、过程及它们之间的关系,以及某些景观特性均表现出尺度效应,因此多尺度研究非常必要和重要.多尺度空间格局分析（尤其是特征尺度的识别）是进行尺度效应分析和跨尺度推绎的基础.多尺度分析需要特定的方法,景观指数法是最常用和最简单的方法,但也常产生误导;空间统计学方法（如半方差分析法、尺度方差分析法、空隙度指数法和小波分析法等）和分维分析法在最近十几年发展起来,并逐渐应用于生态学,在尺度分析上具有很大的应用潜力.各种方法在尺度分析上各有优势和不足,有必要同时使用两种或两种以上方法进行比较和评估.总之,有关尺度分析的研究需要进一步加强,从而为下一步的尺度推绎提供可靠的依据.     

赤腹松鼠采食选择的季节性变化

2008年9月至2010年8月,对广西宜州龙江河畔赤腹松鼠采食选择的季节性变化进行分析.赤腹松鼠对榕树的采食量最大,约占总采食量的36.53%,食物采食选择的种类存在显著差异(P<0.05),各季节采食的种类无显著变化(P>0.05);取食偏好分析、食物生态位宽度和重叠度结果表明,夏季的生态位宽度最大,为4.1545,秋季的生态位宽度最小,为3.5001,夏季和秋季的生态位重叠度最大,为0.9882,夏季和冬季的生态位重叠度最小,为0.9343.     

Uncertainties of Domestic Road Freight Statistics: Insights for Regional Material Flow Studies

Freight statistics are at the core of many studies in the field of industrial ecology because they depict the physical interdependencies of territories and allow links to be made worldwide between production and consumption. Recent studies have focused increasingly on subnational scales, often relying on domestic freight data. In this perspective, this article analyses the uncertainties of the French domestic road freight survey, road being by far the most common mode of transport in the country. Based on a statistical analysis of the survey, we propose a model to estimate the uncertainty of any given domestic road transport flow. We also assess uncertainty reduction when averaging the flows over several years, and obtain for instance a 30% reduction for a three‐year average. We then study the impact of the uncertainties on regional material flow studies such as the economy‐wide material flow analysis of the Bourgogne region. Overall the case studies advocate for a systematic assessment of freight uncertainties, as neither the disaggregation level nor the quantities traded are good enough predictors. This justifies the need for an easy‐to‐implement estimation model. Finally, basic comparison with the German and Swedish surveys tends to indicate that the main conclusions presented in this article are likely to be valid in other European countries.