Threats to at-risk salmonids of the Canadian Rocky Mountain region     

R. Niloshini Sinnatamby  Ariane Cantin  John R. Post 《Ecology of Freshwater Fish》2020,29(3):477-494

Trout and charr, members of the salmonid family, have high conservation value but are also susceptible to anthropogenic threats in part due to the specificity of their habitat requirements. Understanding historical and future threats facing these species is necessary to promote their recovery. Of freshwater trout and charr in the Canadian Rocky Mountain region, westslope cutthroat trout (Oncorhynchus clarkii lewisi), bull trout (Salvelinus confluentus; a charr species) and Athabasca rainbow trout (Oncorhynchus mykiss) are of conservation concern. And indeed, range contractions and declining populations are evident throughout much of their ranges. Range contraction was most evident in the southern Alberta designatable unit (DU) of westslope cutthroat trout. Diminished populations were also evident in the downstream watersheds of the Alberta bull trout range, and throughout the Athabasca rainbow trout range. We assessed historical and future threats to evaluate the relative importance of individual threats to each DU and compare their impact among species. Individual threats fall into the broad categories of angling, non-native species and genes, habitat loss and alteration, and climate change. Severity of each threat varies by DU and reflects the interaction between species’ biology and the location of the DU. Severity of threats facing each DU has changed over time, reflecting extirpation of native populations, changes in management and industry best practices, expansion of non-native species and progressing climate change. The overall threat impact for each DU indicates a high probability of substantial and continuing declines and calls for immediate action.  相似文献   

有色黏虫板对柑橘木虱的监测及防治研究进展   总被引：1，自引：0，他引：1  

许炜明  李翌菡  张盛  沈祖乐  邱宝利 《热带作物学报》2017,(1):183-188

柑橘黄龙病是柑橘生产中的重大病害,随着其在全球范围内的传播蔓延,该病已成为近年来柑橘生产和研究中普遍关注的热点。柑橘木虱(Diaphorina citri Kuwayama)是传播柑橘黄龙病菌(Candidatus Liberibacter asiaticus)的主要虫媒,对柑橘木虱种群的准确监测与有效防控是控制柑橘木虱传播黄龙病的关键所在。有色黏虫板是一种利用昆虫趋色性,对小型飞行昆虫进行监测与诱杀的重要物理防治手段。有色黏虫板同样适用于监测和诱捕柑橘木虱,但黏虫板的颜色、光源、气候条件、悬挂黏虫板的植物种类及其挥发性信息化合物成分等都会影响黏虫板对柑橘木虱的诱集效果。本文在综合国内外柑橘木虱防控技术的基础上,将近年来利用有色黏虫板,监测与防控柑橘木虱的最新进展进行综述,并对有色黏虫板的发展前景给予展望。  相似文献   

Bulk pollen pollination in maize for efficient construction of introgression populations with high genome coverage     

Pingxi Wang  Hongwei Zhang  Demar lyle  Dongdong Li  Guoying Wang  Qingchun Pan  Jianhua Wang 《Plant Breeding》2019,138(3):252-258

Introgression populations consist of a set of introgression lines or families, constructed by continuous backcrossing to the recurrent parent, while carrying a limited number of chromosome segments from a donor parent in their genomes. Increasing the genome coverage is an important aim when constructing introgression population. In this study, we proposed bulk pollen pollination (BPP) method and used it to increase the genome coverage of a maize introgression population. The results showed that the genome coverage of the introgression population constructed using BPP method reached 100% at BC₃ generation, which accorded with the simulation result. The BPP‐based BC₃F_1:2 population could identify most quantitative trait loci (QTL) detected using the F_2:3 population, especially major QTL. Simulation analysis showed that the genome coverage of introgression population increased with the increase of population size and the number of bulked plants, and decreased with the increase of backcross generation. Our results proved the reliability of the BPP‐based introgression population in increasing genome coverage and detecting QTL, and provided references for constructing high‐coverage introgression populations.  相似文献   

校园环境噪声监测与评价--以华中师范大学为例     

仇浩然  姜艳 《绿色科技》2020,(6):102-105

环境噪声是环境质量评价的重要指标。通过噪声监测实验,记录了华中师范大学校园内的噪声污染数据,根据国家标准评估了校园环境噪声状况。试验采用网络剖分法,分别于昼间7:30~10:00和夜间22:00~22:55两个时间段对等效声级进行了测定。实验结果表明:昼间噪声污染更为严重,平均噪声超标率达到26%,夜间噪声污染相对较轻,但噪声超标率也达到19%。校园内不同功能区的噪声来源不同,工程施工产生的噪声是主要的污染源,影响比重达到58%。根据实验结果,校园声环境质量一般,需要对现状提出合理的改进建议。  相似文献   

气象因子对芒果园桔小实蝇种群动态的影响     

邢楚明  韩冬银  张方平  牛黎明  符悦冠 《热带作物学报》2017,37(4):48-51

桔小实蝇[Bactrocera dorsalis (Hendel)]是芒果的重要害虫之一。试验利用性引诱剂对芒果园桔小实蝇的全年种群动态进行监测，分析气象因子与其种群数量变动的相关性。结果表明，芒果园桔小实蝇雄虫种群数量一年有2个明显高峰，2月为短时高峰，3月种群活动有所下降；5月开始数量逐渐升高，至8月达到高峰，9月开始逐渐下降，到12月至1月为发生低谷。经逐步回归分析发现，气象因子显著影响桔小实蝇雄虫的数量，主要受月平均气温、月平均最低气温和月降水量综合影响。  相似文献   

光肩星天牛的成虫监测和适期防治分析     

黄伟 《林业科技情报》2020,52(1):55-57

以光肩星天牛的发生规律和危害特征为基础,应用引诱剂对其成虫进行动态监测,根据监测数据并结合其生活习性确定防治适期和防治方法,为光肩星天牛的监测和防治提供参考。  相似文献   

绿色超级稻品种的农艺与生理性状分析   总被引：2，自引：0，他引：2  

许阳东  朱宽宇  章星传  王志琴  杨建昌 《作物学报》2019,45(1):70-80

探明绿色超级稻的农艺与生理性状,对于培育和选用绿色超级稻品种有重要意义。本研究以4个绿色超级稻品种为材料,1个超级稻品种和1个非超级稻品种为对照,观察了绿色超级稻的农艺与生理表现。结果表明,与对照品种相比,绿色超级稻品种具有较高的产量和氮素利用效率。绿色超级稻品种较高的产量得益于总颖花数和结实率的同步提高,较高的氮素利用率主要在于较高的植株氮素籽粒生产效率(氮素内部利用效率)。绿色超级稻具有较高的茎蘖成穗率和粒叶比,抽穗期较高的糖花比,灌浆期较高的作物生长速率、净同化率、根系氧化力和茎中同化物向籽粒的运转率和成熟期较高的收获指数。这些性状与产量及植株氮素籽粒生产效率均呈极显著的正相关。建议将上述性状作为培育和选用绿色超级稻品种的参考指标。  相似文献   

基于RGB颜色空间的早稻氮素营养监测研究   总被引：1，自引：1，他引：0  

叶春  刘莹  李艳大  曹中盛  张丽娜  刘继忠 《中国农业大学学报》2020,25(8):25-34

针对双季稻区水稻过量施肥带来环境污染和成本提高问题,设计不同品种氮肥梯度大田试验,应用数码相机获取早稻冠层数字图像,研究不同色彩参数及早稻氮素营养指标的时空变化特征,以期确立双季早稻氮素营养预测模型。结果表明:不同品种同一氮肥处理下图像色彩参数差异不大;拔节期数字图像参数对氮素营养指标敏感;模型构建结果显示,图像参数INT与水稻氮素营养指标构建的模型决定系数(R2)最大,模型预测效果最佳,R2分别为0.895 7和0.924 7;进一步采用多元回归分析和BP神经网络分析法进行预测,预测效果均较好。对预测结果进行检验,发现品种对于模型的构建影响不大,以BP神经网络分析法构建的叶片氮浓度(LNC)模型和以INT为敏感色彩参数构建的叶片氮积累量(LNA)回归模型效果最优,而多元回归分析方法则效果不佳。早稻冠层RGB颜色空间敏感参数与氮素营养指标间相关性较好,可以实现氮素营养的无损监测诊断。  相似文献   

Soil protection for a sustainable future: options for a soil monitoring network for Ireland          下载免费PDF全文

L. O'Sullivan  F. Bampa  K. Knights  R. E. Creamer 《Soil Use and Management》2017,33(2):346-363

The increased recognition of the importance of soil is reflected in the UN Post‐2015 Development Agenda with sustainable development goals that directly and indirectly relate to soil quality and protection. Despite a lack of legally binding legislation for soil protection, the European Commission remains committed to the objective of soil protection. However, the achievement of a legally binding framework for soil protection relies on the implementation of a soil monitoring network (SMN) that can detect changes to soil quality over time. As beneficiaries do not pay for the provision of soil information, the options for soil monitoring are limited. The use of existing data sets should be considered first. Using Ireland as an example, this research explored the opportunities for a SMN for Ireland considering three existing national data sets. The options for a SMN are considered in terms of their spatial and stratified distribution, the parameters to be measured and an economic analysis of the options proposed. This research finds that for Ireland, either a 10 or a 16 km² grid interval stratified by land use and drainage class offers the best potential in relation to the spatial distribution of existing data sets to reflect local data at a national level. With existing data, the stratified SIS data using the 16 km² grid offers the best value for money, with baseline costs for analysis, excluding field costs, of between €706 481 and €2.8 million. Acknowledging the impossibility of measuring all parameters with ideal frequency, this study proposes a two‐tier system for optimized monitoring frequency. Parameters must anticipate future policy requirements. Finally, the implementation of a SMN must be accompanied by standardized methods, defined thresholds and action mandates to maintain soil quality within allowable limits.  相似文献   

Effect of transferring lignocellulose-degrading bacteria from termite to rumen fluid of sheep on in vitro gas production,fermentation parameters,microbial populations and enzyme activity          下载免费PDF全文

Ayoub AZIZI  Afrooz SHARIFI  Hasan FAZAELI  Arash AZARFAR  Arjan JONKER  Ali KIANI 《农业科学学报》2020,19(5):1323-1331

The digestive tract of termite(Microcerotermes diversus) contains a variety of lignocellulose-degrading bacteria with exocellulases enzyme activity, not found in the rumen, which could potentially improve fiber degradation in the rumen. The objectives of the current study were to determine the effect of inoculation of rumen fluid(RF) with three species of bacteria isolated from termite digestive tract, Bacillus licheniformis, Ochrobactrum intermedium, and Microbacterium paludicola, on in vitro gas production(IVGP), fermentation parameters, nutrient disappearance, microbial populations, and hydrolytic enzyme activities with fibrous wheat straw(WS) and date leaf(DL) as incubation substrate. Inoculation of RF with either of three termite bacteria increased(P0.05) ammonia-N concentration compared with the control group(free of termite gut bacteria). Termite bacteria inoculation had no effect(P0.05) on gas production characteristics, dry matter, organic matter and neutral detergent fiber disappearance, pH, and concentration and composition of volatile fatty acids. Population of proteolytic bacteria and protozoa, but not cellulolytic bacteria, were increased(P0.05) when RF was inoculated with termite bacteria with both WS and DL substrates. Inoculation of RF with termite bacteria increased protease activity, while activities of carboxymethyl-cellulase, microcrystalline-cellulase, α-amylase and filter paper degrading activity remained unchanged(P0.05). Overall, the results of this study indicated that transferring lignocellulose-degrading bacteria, isolated from digestive tract of termite, to rumen liquid increased protozoa and proteolytic bacteria population and consequently increased protease activity and ammonia-N concentration in vitro, however, no effect on fermentation and fiber degradation parameters were detected. These results suggest that the termite bacteria might be rapidly lysed by the rumen microbes before beneficial effects on the rumen fermentation process could occur.  相似文献