Effect of environmental conditions on the seasonal and inter‐annual variability of small pelagic fish abundance off North‐West Africa: The case of both Senegalese sardinella

The objective of this study was to assess the effect of environmental variations on the abundance of Sardinella aurita and Sardinella maderensis in Senegalese waters in the upwelling system. Monthly data indicating the abundance of sardinella were first estimated from commercial statistics, using Generalized Linear Model from 1966 to 2011. Abundance indices (AIs) were then compared with environmental indices, at the local scale, a Coastal Upwelling Index (CUI) and a coastal Sea Surface Temperature (SST) index, and on a large scale, the North Atlantic Oscillation (NAO), the Atlantic Multidecadal Oscillation (AMO) and the Multivariate El Niño Southern Oscillation Index (MEI), using correlations and times series analyses. The results showed that the abundance of sardinella is determined by a strong seasonal pattern and inter‐annual fluctuations. The abundance of S. aurita peaked in spring and in autumn, whereas that of S. maderensis peaked in the warm season (July–September). The trend of the sardinella abundance was significantly correlated with the CUI, especially in autumn and spring. Interannual fluctuations of S. maderensis and S. aurita abundance are, respectively, driven by the precocity and the duration of the upwelling season that is attributed to distinct migration patterns. Both sardinella species also respond with a delay of around 4 years to the winter NAO index and the autumn CUI, and the AMO index, respectively, both related to migration patterns. The wide variations in sardinella biomass are caused by variations in environmental conditions, which should be considered in the implementation of an ecosystem‐based approach in sardinella stocks management.     

盱眙县龙虾养殖气候适宜性区划

利用盱眙县酸雨资料、气象资料、土壤类型资料以及DEM数据,选取夏季高温日数、酸雨、土壤类型,海拔高度等作为影响龙虾生长的关键因子,采用层次分析法建立了综合气候适宜性区划指标模型,借助ArcGis 10.0技术平台得到盱眙地区龙虾养殖发展的气候适宜性区划图。研究结果表明盱眙县龙虾养殖适宜区主要分布在盱眙县北部,较适宜区主要位于县内东南部丘岗地带,不适宜区位于盱眙县西南部的低山丘陵地带。本研究结果可为盱眙县龙虾养殖规划布局提供一定的参考依据。     

Signals of summer drought in crown condition data from the German Level I network

Crown transparency estimates of Scots pine, Norway spruce, common beech, pedunculate and sessile oak, annually surveyed between 1990 and 2004 within a grid over Germany, provide a suitable response variable to study drought effects on forest trees. Major climatic factors, available on a monthly basis as plot-specifically interpolated values and parameters of site and stand conditions, biotic and other relevant factors were used as predictors in different cross- and length-sectional, and longitudinal models. Stand age is a considerable and most constant driver of crown transparency in all species. Pine, spruce and beech responded—mainly with a delay of 1 year—with some foliar loss in areas where there was a surplus of temperature after the generally hot and dry summer of 2003. Parallel time-series analyses delivered species-specific geographic large-scale patterns with delayed or recent precipitation deficits or temperature surpluses. Even if beech is partly responding in current years with leaf loss towards precipitation surpluses, defoliation is especially high 1 year after hot summers, partly a result of high seed sets after such summers. Crown condition of oak responds in dry and warm areas according to the drought stress hypothesis, however, in cool and wet mountainous ranges oak responds after wet summers with higher defoliation. Longitudinal approaches revealed for all 4-tree species significant relationships between crown condition and deviations from the long-term means of temperature, precipitation but also global radiation and wind speed. Results do not always match the drought stress hypothesis, however, this is not to expect considering the heterogeneous site, stand and climatic conditions across Germany. Complex interactions of climatic and biotic factors also impede simple relationships. Soil-related clusters reveal higher sensitivity of spruce and beech towards climatic drought factors on more acid soils with thin humus layers. Also clusters constructed from plot-specific courses of defoliation reveal groups with rather closer relationships like a group of pine plots in the Oberpfalz, which seems to be especially sensitive to summer drought.     

白藤花粉采集时间及萌发条件的初步研究

对白藤开花习性、花粉采集时间及萌发条件进行了初步研究,结果表明：在白藤开花盛期,日开花高峰期集中在早晨4：00～8：00,其中6：00开放的花朵占当日开花总数的62．36％,其他时段开花量极少;上午8：30～11：30收集的花粉萌发力最强;在25％蔗糖液体培养基中和35℃下培养6h,花粉萌发与生长效果最佳。     

Relationships of climate change and tree ring of Betula ermanii tree line forest in Changbai Mountain

Based on the tree-ring growth characteristics of Erman＇s birch （Betula ermanii charm.） and the relationships between it and climatic ）＇actors at elevation of 1950m, the sensitivity of tree lines in Changbai Mountain to climatic factors was assessed. The results indicated tree line forest in Changbai Mountain had an obvious sensitivity to climate factors. However, difference from other study sits is that the main climatic control factor on tree-ring growth was not current growth season temperatures, as might be expected, but previous winter and current March temperature. Although the precipitation in the region was quite abundant, the tree-ring growth was still significantly correlated with the precipitation during previous winter and current spring. Additionally, climatic factors which influenced the Erman＇s birch growth were not the yearly variables, but seasonal and monthly variables. Therefore, the reported increase in yearly mean temperature and total yearly precipitation since 1980s was not responded by sustained increase in ring widths in recent decades.     

四川省竹类引种的研究

本文报导四川竹类引种的概况,作者曾同有关人员自7省引入竹种20属、130种。其中:省外、国外10属、56种。在四川省林科院成都林业试验场,作栽培驯化试验后,又引至灌县、长宁、纳溪等县栽培的生长调查数据;并按在我国引种10个县(市)的7个气候因子,运用因子分析方法,作气候区划。再结合四川省的地形地势、地质、土壤、气候、植被、竹类分布和竹子引种成效,作竹类引种初步区划,提出区划为4个竹类引种分区意见,以便分别制定适宜的引种栽培措施,使竹类生长适合本地的生态环境,为进一步发展竹类资源,提供科学依据。     

近10年青海共和地区霜冻气候特征与历史特征的对比分析

利用青海省共和县气象局观测的1961—2017年逐日最低气温资料,采用线性倾向估计、绝对变率、保证率等分析方法,对共和地区≤0℃霜冻初日、终日、无霜期变化特征进行分析,为有效利用共和地区农业气候资源提供科学参考依据,对该地区的农业生产起到积极有效的指导和促进作用。     

"早稻-冬草莓"轮作模式最佳种植期研究

[目的]研究"早稻-冬草莓"轮作模式最佳种植期.[方法]根据双流县气象局1971 ～ 2010年气象资料,采用滑移气候相似距及数理统计方法,对"早稻-冬草莓"轮作模式最佳种植期进行分析.[结果]冬草莓最佳种植期在8月1日～翌年3月31日,其小苗移栽最早在7月中旬,最晚在8月中旬,最佳移栽时期平均在8月19日.早稻移栽时间平均为3月26日,拟收获期平均为7月26日.[结论]从气象角度研究了"早稻-冬草莓"轮作模式最佳种植期,为双流县推广该模式,最大限度地发挥光、温、水、土地的生态效益提供了科学的决策依据.     

Optimal utilisation of natural resources for agricultural sustainability in rainfed hill plateaus of Orissa

The climatic data for 17 years from 1988 to 2004 of the rainfed hill plateaus of Kandhamal district of Orissa (India) were analyzed to find out the monthly climatic index from the calculated values of effective rainfall and evapotranspiration. The 80% dependable monthly climatic index was correlated with crop coefficient and suitable cropping period and sequences for the study area were suggested based on it. The extent of investment, net return and soil loss from agriculture were estimated as per the present condition and for the suggested cropping patterns. A mathematical model was formulated for optimal allocation of area to different crop sequences with different objectives viz. minimization of soil loss, minimization of investment and maximization of net return from agriculture and was solved using linear goal programming technique. The model suggested to take up food crops in area of 1,30,777 ha and perennial grass cover in 3223 ha with a cropping intensity of 1.61 resulting in a net return of Rs 1064.775 millions sustaining soil loss to a tune of 9489.67 thousand tons per year. The model was found to be favourable in respect of higher net return of Rs 8862.34 and lesser soil loss of 23.41 tons/ha than the corresponding present values. But more investment of Rs 4489.01 per ha was required to fulfill the objectives.     

王朗自然保护区岷江冷杉林(Abies faxoniana)更新及其种群结构分析

岷江冷杉(Abies faxoniana)林是四川王朗自然保护区主要群落类型,本文选择典型的亚高山针叶原始林设置标准样地,对其幼苗幼树查数轮生枝、大树钻取树轮样芯确定个体年龄,分别建立苗高-年龄、胸径-年龄的回归方程得到整个种群的年龄结构,通过编制生命表对其进行生存分析.结果表明,岷江冷杉存活曲线属于Deevey-Ⅲ型...