Late-arriving barn swallows linked to population declines

Barn swallows (Hirundo rustica) are arriving later in the spring than they did 30–40 years ago at numerous sites in Korea. In some cases their arrival times are later by more than 1 month. This result is perplexing as spring activities of plants and animals are generally getting earlier due to warming temperatures. The first arrival dates of swallows are not related to temperature, suggesting that another factor is involved. On the basis of a questionnaire, a large majority of long-term observers are confident that there has been a moderate to severe decline in swallow populations at their field site over the study period. The greatest delays in arrival times are associated with sites with more severe reported declines in population size. Simulations using trapping data of large migratory bird populations from the United States, consisting of hundreds of individuals, suggest that severe population declines of 99% can result in delays of 10–12 days in arrival times. In summary, our results suggest that the large delays in arrival time of Korean swallows are due, at least in part, to severe reductions of more than 99% in what were formerly very large populations. Significant delays in spring phenology over time during a period of climatic warming may indicate population decline, though alternative explanations, such as changes in range or migration path or changing number of broods per season, should also be investigated. Delays in first arrival data can provide a valuable new tool to conservation biologists by indicating declines in a population that would otherwise go unnoticed. This can, in turn, lead to efforts by researchers to verify the dynamics of a population and draw attention to the conservation needs of the species.     

The origin of Manihot esculenta Crantz (Euphorbiaceae)

Summary Contrary to views that cassava (Manihot esculenta) is only known in cultivation an argument is made that wild accessions of the species grow over much of the American neotropics, in Brazil, Bolivia, Peru, Venezuela, Guyana, and Surinam. Three subspecies are recognized. M. esculenta subsp. esculenta is the domesticate and includes all cultivars known in cultivation. The wild M. esculenta subsp. peruviana occurs in eastern Peru and western Brazil. The wild M. esculenta subsp. flabellifolia shows a wider distribution and ranges from the central Brazilian state of Goiás northward to Venezuelan Amazonia. The large area of distribution of the two wild subspecies makes it difficult to assign a place of initial domestication.     

Multiple effects of urbanization on the biodiversity of developing countries: The case of a fast-growing metropolitan area (Concepción, Chile)

Urbanization is increasingly homogenizing the biota of less developed countries. Even though urban sprawl is a worldwide problem, most studies on the effects of urbanization, and the conceptual models have focused on developed countries. South America has not escaped urbanization, and here we discuss the potential impacts of urban sprawl with respect to three ecosystems in the metropolitan area of Concepción, Chile. We consider this area a good model and fairly representative of other cities in developing countries which are also experiencing rapid and uncontrolled growth. We found that the impacts of urban sprawl on biodiversity in the metropolitan area of Concepción differ little from cities in other parts of the world: native ecosystems are replaced by pavements and buildings and what is left of the natural soil is covered with green areas dominated by non-native ornamental species. Wetlands and other peri-urban ecosystems are rapidly being destroyed, fragmented or invaded by non-native species. We found that from a study area of 32,000 ha, there was a net loss to urbanization of 1734 ha of wetlands (23% of the original) and 1417 ha (9%) of agricultural, forest and shrub land cover types between 1975 and 2000. From the total area urbanized (3151 ha), 55% corresponded to wetlands and 45% to agricultural, forest and shrub lands cover types. We see the lack of environmental awareness as a major cause of the increasing deterioration of biodiversity in urban areas of developing countries. More research is needed to fully understand the effects of urban sprawl on the biodiversity of developing countries to include these ecosystems in global conservation strategies.     

南水北调东线工程对上海地区生态环境的影响及应对措施

南水北调东线工程实施后,长江枯水期对其污水自净能力将会有一定程度的降低,因此,目前上海市污水排放会对长江口湿地和河口生态环境的影响将发生微妙的变化。通过分析近10年来长江口生态环境的变化趋势,及上海市污水排放和治理现状,研究了南水北调东线工程调水后对上海地区生态环境新的主要影响,并针对污水排放及长江口生态环境问题,分别提出了相应的建议性应对措施。     

华南海岛土壤形成的地球化学

The soils in South China sea Islands(SCSI)were divided into three types,nmaely,phospho-calc soils,skeletisols and coastic solonchake,which were derived from bio-clastic and strongly calcareous sediments.In comparison with their parent materials,the phospho-Calc soils have higher contents of P,Zn Cu,Ba,and Cd,which tend to increase gradually with time,and lower contents of Mg,Ca,Sr,B,V,Pb,and Mo,which tend to decrease by degrees with time,The above-mentioned constituents in skeletisols and coastic solonchaks are similar to those in their parent materials except for P and Na,The factors affecting element distribution are mainly special bioclimate and parent material,meanwhile,resulting in the remakable influence on element distribution through soil-forming time.     

我国南方设施园艺气候区划的研究

选择对南方设施园艺发展起关键作用的气候因子为指标 ,利用主成分、聚类分析和判别分析进行多指标综合分区 ,将我国南方设施园艺发展区域分为 5个气候区 ,并分析了各区设施园艺现状和发展趋势 ,提出发展建议     

论《孝经》对“中韩”道德发展及其社会现代化转型的意义

《孝经》及其蕴涵的孝道孝德是中国传统文化的文明精髓之一,也是中国传统道德的核心内容。它不仅形塑了中国古代的道德文化,化育了中国人的人格品质和行为范式,而且深深地影响了中国的近邻尤其是东亚的朝鲜民族的精神风貌和道德取向,成为中国和韩国在社会现代化转型过程中中和西方个体本位价值观念的冲击,克服现代文明病,构建社会和谐的重要精神资源。     

南海北部冬季和夏季浮游哲水蚤类群落

在2015年夏季和冬季开展了南海北部海域不同粒级浮游动物碳稳定同位素特征的研究。按照浮游动物粒径大小将其分成3个类群：小型(180~380 μm)、中型(380~500 μm)和大型(>500 μm)。研究结果表明,浮游动物δ¹³C值空间分布差异明显,夏季浮游动物δ¹³C值变化范围为–24.19~ –19.57,小型和中型浮游动物δ¹³C值的高值均分布在研究海域南部;冬季浮游动物δ¹³C值变化范围为–23.89~ –19.69,空间分布特征与夏季相反。浮游动物δ¹³C值未表现出显著的季节和粒径结构差异。各粒级浮游动物δ¹³C值与叶绿素a平均浓度的对数值均呈显著的正相关,而与浮游动物生物量相关性不明显。     

南海北部的金线鱼

根据2014年8月—2015年2月于南海北部海域采集的金线鱼(Nemipterus virgatus) 106尾,测量其耳石样本的长、宽、周长、面积等形态指标,分析耳石形态特征,以探讨其耳石形态特征与个体体长、体质量的关系。结果表明,金线鱼耳石的形态指标在雌、雄个体间差异不显著(P>0.05)。耳石的宽、面积及长宽比在左右耳石之间存在显著性差异(P<0.05),但耳石的长、最大半径、最小半径、周长、最小外接矩形面积和半径比在左右耳石之间差异不显著(P>0.05)。经主成分分析发现,耳石的长、宽、最大半径、最小半径、周长、面积、最小外接矩形面积和半径比这8个形态指标为金线鱼耳石的主要形态指标。金线鱼耳石主要形态指标与体长、体质量的最佳拟合函数为多项式函数。     

3个南非耐旱引进树种在云南省的生长适应性初步研究

引进南非干热逆境地区的Acacia karoo、Acacia nilotica、Albizia adiolutica 3个含羞草科(MIMOSACEAE)树种在云南进行生长适应性研究结果表明,在各试验点生长保存情况各自不同.在3个试验点,Acacia karoo生长都优于其他2个树种,Albizia adiolutica生长都较差.此外,3个树种在3个代表云南省不同气候的试验点的生长与试验点关键气候因子的相关性分析表明,3个树种都对炎热干燥的气候有明显的适应性,而不适宜种植在降雨丰富和湿度较大的地区.