Spatial and interspecific variability in phenological responses to warming temperatures     

Richard B. Primack  Ins Ibez  Hiroyoshi Higuchi  Sang Don Lee  Abraham J. Miller-Rushing  Adam M. Wilson  John A. Silander Jr. 《Biological conservation》2009,142(11):2569-2577

A comprehensive understanding of species phenological responses to global warming will require observations that are both long-term and spatially extensive. Here we present an analysis of the spring phenological response to climate variation of twelve taxa: six plants, three birds, a frog, and two insects. Phenology was monitored using standardized protocols at 176 meteorological stations in Japan and South Korea from 1953 to 2005, and in some cases even longer. We developed a hierarchical Bayesian model to examine the complex interactions of temperature, site effects, and latitude on phenology. Results show species-specific variation in the magnitude and even in the direction of their responses to increasing temperature, which also differ from site-to-site. At most sites the differences in phenology among species are forecast to become greater with warmer temperatures. Our results challenge the assertion that trends in one geographic region can be extrapolated to others, and emphasize the idiosyncratic nature of the species response to global warming. Field studies are needed to determine how these patterns of variation in species response to climate change affect species interactions and the ability to persist in a changing climate.  相似文献   

Bovine infection with bluetongue virus with special emphasis on European serotype 8     

Fabiana Dal Pozzo  Claude Saegerman  Etienne Thiry   《Veterinary journal (London, England : 1997)》2009,182(2):142-151

Bluetongue virus (BTV) is an arthropod-borne virus infecting domestic and wild ruminants. Infection in cattle is commonly asymptomatic and characterised by a long viraemia. Associated with the emergence and the recrudescence of BTV serotype 8 (BTV-8) in Northern and Central Europe, remarkable differences have been noticed in the transmission and in the clinical expression of the disease, with cattle showing clinical illness and reproductive disorders such as abortion, stillbirth and fetal abnormalities. Several investigations have already indicated the putative ability of the European BTV-8 strain to cross the bovine placenta and to cause congenital infections. The current epidemiological and pathological findings present an unusual picture of the disease in affected bovines.  相似文献   

Antemortem Diagnosis of CDV Infection by RT-PCR in Distemper Dogs with Neurological Deficits without the Typical Clinical Presentation     

Amude AM  Alfieri AA  Alfieri AF 《Veterinary research communications》2006,30(6):679-687

In dogs with neurological disturbances without myoclonus and extraneural signs, the clinical diagnosis of distemper is difficult perform. Considering the great infectious potential of the disease, the possibility of carrying out an antemortem diagnosis of distemper is important, particularly in hospitalized patients with neurological disease. The present study was carried out to evaluate RT-PCR for antemortem CDV detection in hospitalized dogs with neurological disturbances without the typical findings of distemper. We investigated five dogs with canine distemper virus (CDV) encephalomyelitis, in which the clinical diagnosis was not performed owing to the absence of characteristic signs of the disease, such as myoclonus and systemic signs. We observed an apparent high sensitivity of RT-PCR in urine samples for detection of CDV: four out of five urine samples were RT-PCR positive. The results of the present study suggest that urine is a good biological sample for antemortem CDV detection by RT-PCR in dogs with distemper encephalomyelitis in which the clinical diagnosis is likely to be difficult owing to the absence of suggestive distemper signs. The use of two different body fluids (urine and CSF) may increase the RT-PCR sensitivity for antemortem diagnosis of distemper in such cases.  相似文献   

BP神经网络在旅游安全预警信息系统中的应用研究   总被引：1，自引：0，他引：1  

韩林芝  郑江华 《安徽农业科学》2009,37(7):3327-3329

利用BP神经网络对旅游安全预警信息系统的应用进行了研究,并通过BP神经网络模型的构建和仿真试验结果证明了该模型的适用性和可行性。  相似文献   

近60年贵州省清镇市耕地变化研究     

王乐  蔡运龙 《安徽农业科学》2009,37(7):3155-3157

采用地方统计资料分析黔中清镇市1949~2006年耕地的数量变化、1992~2002年耕地变化的空间差异和耕地坡度分布变化,计算最小人均耕地面积和压力指数,建立初步的粮食安全预警机制。研究表明,1949~2006年清镇市耕地变化的总体趋势是不断减少;1992~2002年相对变化率由靠近市区和贵阳的东南部向西北部递减;耕地分布的坡度有向2°~15°集中的趋势;1973年之后,耕地压力指数保持在大于1的水平,处于粮食安全警戒状态;4种情景模拟的结果表明,未来清镇市耕地压力也难以得到缓解。  相似文献   

次生盐渍化对膜下滴灌棉花生长发育的影响及其预警研究   总被引：2，自引：1，他引：1  

孙肇君  李鲁华  张伟  张小伟  杨忠平  常世伟 《新疆农业科学》2009,46(4):751-756

以7块次生盐渍化程度不同的膜下滴灌棉田为研究对象,探明次生盐渍化对新疆棉花生长发育的影响,并以此为基础探讨其状态预警问题.研究结果表明:在各生育期,土壤盐度和棉花株高、干物质重、叶面积指数均呈极显著的负相关关系.生育期不同,影响棉花生长的关键盐度也有所差别.各棉田的警度随着生育期的进行有逐渐减轻的趋势.0.6 dS/m以下的土壤盐度在各生育期都不会对棉花生长造成较大危害,2.8 dS/m以上的土壤盐度在前期更易对棉花生长造成严重影响,到吐絮期2.8 dS/m左右的盐度已不能对棉田造成较大危害.  相似文献   

Effect of vegetation on soil water retention and storage in a semi-arid alpine forest catchment   总被引：2，自引：0，他引：2  

Chao WANG 《干旱区科学》2013,5(2):207-219

The runoff generated from mountainous regions is recognized as the main water source for inland river basins in arid environments. Thus, the mechanisms by which catchments retain water in soils are to be understood. The water storage capacity of soil depends on its depth and capacity to retain water under gravitational drainage and evapotranspiration. The latter can be studied through soil water retention curve (SWRC), which is closely related to soil properties such as texture, bulk density, porosity, soil organic carbon content, and so on. The present study represented SWRCs using HYDRUS-1D. In the present study, we measured physical and hydraulic properties of soil samples collected from Sabina przewalskii forest (south-facing slope with highest solar radiation), shrubs (west-facing slope with medium radiation), and Picea crassifolia forest (north-facing slope with lowest radiation), and analyzed the differences in soil water storage capacity of these soil samples. Soil water content of those three vegetation covers were also measured to validate the soil water storage capacity and to analyze the relationship between soil organic matter content and soil water content. Statistical analysis showed that different vegetation covers could lead to different soil bulk densities and differences in soil water retention on the three slope aspects. Sand content, porosity, and organic carbon content of the P. crassifolia forest were relatively greater compared with those of the S. przewalskii forest and shrubs. However, silt content and soil bulk density were relatively smaller than those in the S. przewalskii forest and shrubs. In addition, there was a significant linear positive relationship between averaged soil water content and soil organic matter content (P<0.0001). However, this relationship is not significant in the P. crassifolia forest. As depicted in the SWRCs, the water storage capacity of the soil was 39.14% and 37.38% higher in the P. crassifolia forest than in the S. przewalskii forest and shrubs, respectively, at a similar soil depth.  相似文献   

城市行道树遮挡道路交通标志问题分析          下载免费PDF全文

顾汤华 《中国城市林业》2013,11(4):39-41

在现场调研和文献资料查阅的基础上,分析行道树遮挡交通标志的问题及原因,从交通标志设置、行道树设置及部门机制等方面提出相关的改善对策。    相似文献   

一次致害雷暴电荷轨迹分布特征研究     

陈连友  居丽玲  孙丽华 《安徽农业科学》2011,39(1):505-507

雷暴是一种能引起严重灾害的自然现象。2007年7月9日,秦皇岛市发生多起雷击事故,局部地点还出现了冰雹。利用＂GDS-2型高精度闪电探测仪＂监测到的雷暴天气和此次雷暴灾害天气过程资料,对出现雷暴、强雷暴灾害的电荷结构、闪电出现频率、闪电放电轨迹分布特征进行了分析。结果表明,7月9日雷暴、冰雹发生时,地面电场电荷以正电荷为主,地面电场闪电放电轨迹具有离散性、集中性和线性特征。揭示了闪电频次〉10次/min出现雷暴灾害、冰雹可能性大;闪电发生的集中地点极有可能出现雷暴、冰雹天气,应当及时预警预报,并建议采取有效措施对该地区进行防护。  相似文献   

我国农业上市公司亏损的财务预警分析——以香梨股份有限公司为例     

李娜 《安徽农业科学》2011,39(35):22172-22174,22178

运用香梨股份有限公司的财务信息,从一般财务分析的角度对它进行研究,通过对财务预警系统在农业上市公司的运用进行分析,说明财务预警对我国农业上市公司的有效程度,以便为我国农业上市公司财务预警提供借鉴与参考。  相似文献