Stream crossings and the conservation of diadromous invertebrates in South Pacific island streams

• 1. Most non‐insect invertebrates that occur in streams on tropical Pacific islands are diadromous; they live as juveniles and adults in streams but have larvae that migrate to the ocean to complete their development before returning to fresh water.
• 2. The type of crossing used in the construction of roads to traverse small streams can impede upstream migration and, consequently, colonization of diadromous fauna above the stream crossing.
• 3. A stream in the Opunohu Valley, Moorea, French Polynesia, had the same diadromous fauna of atyid shrimps, palaemonid prawns, and neritid snails occurring above and below an 8 m wide, 10 m long, bottomless culvert (i.e. an open‐bottom bridge) built to flow over natural substrates. However, no diadromous species were found upstream of two 1 m diameter, 8 m long concrete pipes used for a culverted stream crossing. The increased shear stress in the pipe and subsequent downstream erosion of the stream bed probably inhibited upstream migration.
• 4. Modifications to culverted stream crossings, which are widely used on tropical islands, can reduce migration barriers and prevent upstream loss of diadromous stream fauna.

Copyright © 2004 John Wiley & Sons, Ltd.     

影响南非肉用美利奴羊生长性状的非遗传因素

根据山西省沁水示范牧场2005—2008年度出生的183只羔羊的0-12月龄的生长记录,采用SPSS 17.0软件分析了羔羊出生年份、出生月份、出生类型、母亲年龄、哺育类型和性别等非遗传因素对南非肉用美利奴羊生长性状的影响。结果表明：①出生年份和母亲年龄对初生重的影响极显著（P〈0.01）;②出生年份、出生月份和性别对断奶重的影响极显著（P〈0.01）;③出生年份和性别对周岁重的影响极显著（P〈0.01）;④出生类型和性别对初生重的影响显著（P〈0.05）;⑤其余各因素对体重影响均不显著（P〉0.05）。这些结果可为今后估计南非肉用美利奴羊遗传参数和育种值时固定效应的划分提供科学依据,为该品种早期选种奠定基础。     

进口牙鲆工厂化养殖及鱼病防治试验

１９９４年６月中旬从韩国出口７～１３ｇ／尾牙鲆苗８万尾，利用室内循环水锅炉升温进行工厂化养殖９个月，平均体重５００ｇ以上，达到商品规格，养殖过程中，试验了放养密度，投饵，水质管理及腹水病，纤毛虫病的防治技术。     

南海主要珊瑚礁(鱼旨)科鱼类的组成与分布

1998年3~5月和1999年5~6月,采用手钓、延绳钓和刺网3种作业方式在西沙的浪花礁、华光礁、琛航岛、永兴岛、北礁和南沙的渚碧礁、南薰礁、东门礁、美济礁、赤瓜礁、永署礁、华阳礁等12座珊瑚礁水域进行了2个航次的鱼类资源调查,捕获科鱼类6属25种,渔获量计942尾256.4kg;其中在南沙调查区捕获6属22种,共641尾205.5kg,优势种依次为尾纹九棘鲈、蜂巢石斑鱼、六角石斑鱼、黑边石斑鱼;在西沙调查区捕获6属14种,共301尾50.9kg,优势种依次为尾纹九棘鲈、六角石斑鱼、黑边石斑鱼、蜂巢石斑鱼,同时分析了主要种类尾纹九棘鲈、六角石斑鱼和蜂巢石斑鱼的生物学特征。     

东海北部和黄海南部鲐鱼生长特性及合理利用

采用2002年11月~2003年8月在东海北部和黄海南部区域(30°~34°N、126°E以西范围)所获取的鲐鱼(Scomberjaponicus)样品,通过观察鲐鱼耳石生长轮和基础生物学测定,研究了鲐鱼的年龄和生长;再依据不完全β函数渔获量方程,计算、分析在不同开捕年龄和不同捕捞强度下的单位补充量渔获量(Yw/R)的变化情况。结果表明,采用Walford方法拟合的鲐鱼生长方程,其生长参数K、L∞、t0分别为0.320、451.4和-1.203。比较不同时期鲐鱼的生长情况显示,20世纪60、80年代和21世纪初期鲐鱼的生长较接近,而20世纪70年代的鲐鱼生长情况与其他3个时期的鲐鱼生长相差较大。比较不同海域鲐鱼的生长情况显示,随着纬度的增加,鲐鱼的个体有增大的趋势,经分析很可能与海水温度有关。根据历史资料推算出鲐鱼的最大年龄(tλ)为9龄;根据最近的采样,推算出鲐鱼的开捕年龄和补充年龄都为0.4年,鲐鱼的自然死亡率为0.355,捕捞死亡率为2.27。利用上述参数,动态综合模型模拟的结果显示,该资源过度捕捞已很严重。若保持当前捕捞强度,则必须把开捕年龄限制在2.9龄;若能同时改变捕捞强度和开捕年龄,则可以把当前的开捕年龄限制在2.0龄,捕捞死亡率降到1.3,这样鲐鱼资源才能够得到保护与合理利用。     

增密条件下Cabrio和Opera对夏玉米植株发育及产量的影响

以郑单958、浚单20为试验材料,设定60 000株/hm²、75 000株/hm²两个密度,研究夏玉米产量与产量构成因素、干物质生产、叶面积指数发展动态、光合作用等,探讨喷施Cabrio和Opera试剂对夏玉米植株发育及产量的影响。结果表明,喷施药剂Cabrio和Opera后玉米产量增加,浚单20较对照分别增产6.7%和4.0%;郑单958较对照分别增产5.3%和4.2%。喷施药剂Cabrio和Opera的处理生育后期下部叶片衰老缓慢,吐丝期至成熟期LAI下降幅度较小,单株干物重和单位面积干物质积累增强,光合性能增强,光合速率提高。     

华南芒果种植区寒冻害危险性区划与评估

利用华南（广东、广西、福建）芒果种植区115个气象站1961−2016年观测资料,结合芒果寒冻害指标,采用加权综合评价法,确定种植区各气象站点的寒冻害危险性指数,建立寒冻害危险性指数与地理因子之间的多元线性回归模型,并基于GIS技术对华南芒果种植区寒冻害危险性进行区划。结果表明：华南芒果种植区寒冻害危险性与地理因子之间关系密切,总体呈现由沿海到内陆,寒冻害危险性逐渐变大的趋势,此外,随着纬度和海拔的增高,从南到北芒果寒冻害危险性程度也逐渐增大。轻度危险区主要分布在华南芒果种植区南部沿海地带及部分内陆地市的低海拔地区,占种植区面积比例为56.85%,该区域适合大规模种植芒果;中度寒冻害危险性区域主要分布在华南芒果种植区内陆中低海拔地区以及北部高纬度沿海地区,占种植区面积比例为37.03%;重度以上的寒冻害危险性区域主要分布在华南芒果种植区内陆高海拔地区,占种植区面积比例为6.12%。通过历史灾情和各县区年产量资料验证,区划结果与实际较为吻合,研究结果可为华南地区芒果的优化布局和防灾减灾提供参考。     

新疆南疆一起猪繁殖与呼吸综合征的诊断

为了明确新疆南疆某猪场猪一起疫情发病原因,本研究采用发病情况调查、临床症状检查、病理学剖检、病理组织学观察和RT-PCR方法进行系统分析。结果诊断为该猪场猪感染猪繁殖与呼吸综合征病毒,且初步鉴定为高致病性猪繁殖与呼吸综合征。该诊断结果为该场乃至新疆南疆猪病的诊断和防制提供一定的方法和指导意义。     

滇南、滇东南芒果病虫害种类调查研究

采用定点调查与普查相结合的方法,对滇南、滇东南芒果生产区芒果病虫害分布、危害情况及种类进行了调查,结果鉴定出危害滇南、滇东南芒果生产的病害25种,虫害61种。同时对滇南、滇东南芒果生产的干热区和湿热区病虫害的分布以及差异作了分析。调查结果对于生产上科学制定防治措施,保障滇南、滇东南芒果种植业的持续健康发展具有重要意义。     

Soil CO2 and N2O Emissions in Maize Growing Season Under Different Fertilizer Regimes in an Upland Red Soil Region of South China

Upland red soils have been identified as major CO2 and N2O sources induced by human activities such as fertilization. To monitor characteristics of soil surface CO2 and N2O fluxes in cropland ecosystems after continuous fertilizer applications over decades and to separate the respective contributions of root and heterotrophic respiration to the total soil CO2 and N2O fluxes, the measurements of soil surface CO2 and N2O fluxes throughout the maize growing season in 2009 were carried out based on a fertilization experiment （from 1990） through of the maize （Zea mays L.） growing season in red soil in southern China. Five fertilization treatments were chosen from the experiment for study： zero-fertilizer application （CK）, nitrogen-phosphorus- potassium （NPK） fertilizer application only, pig manure （M）, NPK plus pig manure （NPKM） and NPK with straw （NPKS）. Six chambers were installed in each plot. Three of them are in the inter-row soil （NR） and the others are in the soil within the row （R）. Each fertilizer treatment received the same amount of N （300 kg ha-1 yr-1）. Results showed that cumulative soil CO2 fluxes in NR or R were both following the order： NPKS〉M, NPKM〉NPK〉CK. The contributions of root respiration to soil CO2 fluxes was 40, 44, 50, 47 and 35% in CK, NPK, NPKM, M and NPKS treatments, respectively, with the mean value of 43%. Cumulative soil N2O fluxes in NR or R were both following the order： NPKS, NPKM〉M〉NPK〉CK, and soil N2O fluxes in R were 18, 20 and 30% higher than that in NR in NPKM, M and NPKS treatments, respectively, but with no difference between NR and R in NPK treatment. Furthermore, combine with soil temperature at -5 cm depth and soil moisWxe （0-20 cm） together could explain 55-70% and 42-59% of soil CO2 and N2O emissions with root interference and 62- 78% and 44-63% of that without root interference, respectively. In addition, soil CO2 and N2O flUXeS per unit yield in NPKM （0.55 and 0.10 kg C t^-1） and M （0.65 and 0.13 g N t^-1） treatments were lower than those in other treatments. Therefore, manure application could be a preferred fertilization strategy in red soils in South China.