Spatiotemporal patterns of mountain whitefish (Prosopium williamsoni) in response to a restoration of longitudinal connectivity          下载免费PDF全文

Peter M. Kiffney  Ben Cram  Paul L. Faulds  Karl Burton  Michele Koehler  Thomas P. Quinn 《Ecology of Freshwater Fish》2018,27(4):1037-1053

To examine the role of longitudinal connectivity on the spatial and temporal dynamics of mountain whitefish (Prosopium williamsoni), we quantified movement and population dynamics following installation of the Landsburg Dam fishway, Cedar River, WA, USA. Mountain whitefish is widely distributed, poorly studied and not the focus of restoration. Before the fishway, mountain whitefish were not observed above the dam. Here, we focus on snorkel counts collected at reach and mesohabitat (e.g. pools) scales over 11 summers on the 20‐km above‐dam segment following restoration. A camera within the ladder provided number, size and movement timing, thereby informing on behaviour and recolonisation. Segment‐scale abundance increased following fish passage reaching an asymptote in 7 years, and mountain whitefish were detected throughout the main stem in 10 years. Annual movement through the ladder increased over time and was positively correlated with instream abundance and discharge, but negatively correlated with water temperature. About 60% of fish movements occurred in spring and early summer, potentially for foraging opportunities. Reach‐scale abundance peaked between 7 and 10 km from the dam; deep, cool (~10.6 to 11.6°C) conditions characterised these reaches. At the mesohabitat scale, mountain whitefish detection increased with depth and velocity after accounting for distance from the dam. Our results show how restoring longitudinal connectivity allowed this nontarget species to colonise newly available habitat. Their response supports the critical roles of longitudinal connectivity and environmental conditions, that manifest at different spatial scales, in dictating how freshwater fish respond to habitat disturbance.  相似文献   

葡萄二倍体与四倍体品种间杂交胚珠的离体培养   总被引：12，自引：2，他引：10  

徐海英  阎爱玲  张国军 《果树学报》2001,18(6):317-320

为了克服葡萄二倍体品种与四倍体品种之间的交配障碍,进行了杂交胚珠的离体培养研究。发芽胚珠的取样时期集中于授粉后35～75d,其中多数以二倍体作母本的组合在授粉后55d取样的发芽率最高,以四倍体作母本的组合授粉后70d取样的发芽率最高。基本培养模式为:发育培养基-(剥胚)萌发培养基-生长培养基。用二倍体品种作母本时,所有组合均获得了培养苗,在1号培养基上培养的胚珠发芽率高于2号培养基。反交对培养基的要求有相反趋势,其中2个组合未得到培养苗。授粉后60d,直接剥出杂种胚进行培养,得到了最高发芽率。综合分析初步认为,用二倍体品种作母本比用四倍体品种作母本容易获得杂交后代。  相似文献   

葡萄自交与杂交后代香气成分的遗传研究     

李坤  郭修武  谢洪刚  郭印山  李轶辉  李成祥 《园艺学报》2005,32(2):218-221

 利用气相色谱- 质谱- 计算机联用系统(GC-MC-CS) 对两个自交组合、1个杂交组合亲本及其后代的香气成分进行研究。结果表明: 同一组合中不同香气成分的分离情况不同, 同种香气成分在不同组合中的分离情况也不完全相同。果实香气成分的遗传主要表现为分离( 1∶1、1∶3、3∶1、15∶1) 与不分离两种方式, 发生分离的成分有些是由单基因控制的, 有些是由多基因控制的。  相似文献   

春丰50苦瓜的选育     

刘政国  肖喜祝  李加振 《中国蔬菜》2003,1(6):19-20

以曼谷青皮、碧绿1号和钦州大肉苦瓜为育种材料,采用双父本混合花粉杂交和后代系谱选择育成优良自交系,再经配合力测定选出优良一代杂种春丰50。该品种生长势强,果实粗棒形,纵径26.3cm,横径6.45cm,皮色翠绿油亮,一般单果质量420g左右。平均每667m~2产量3 500kg。  相似文献   

Movement patterns of seaward migrating European eel (Anguilla anguilla) at a complex of riverine barriers: implications for conservation          下载免费PDF全文

Adam T. Piper  Jon C. Svendsen  Rosalind M. Wright  Paul S. Kemp 《Ecology of Freshwater Fish》2017,26(1):87-98

River infrastructure such as weirs and hydropower stations commonly present migrating fish with multiple potential passage routes. Knowledge of the cues fish use to navigate such environments is required to protect migrants from hazardous areas and guide them towards safe passage; however, this is currently lacking for many species. Employing high‐resolution positioning telemetry, this study examined movements of downstream migrating adult European eel, Anguilla anguilla, as they encountered a complex of water control structures in one location on the River Stour, southern England. The distribution of eels across five potential routes of passage differed from that predicted based on proportion of discharge alone. Certain routes were consistently avoided, even when the majority of flow passed through them. Passage distribution was partially explained by avoidance in the vicinity of a floating debris boom. Movement paths were nonrandomly distributed across the forebay and eels moved predominantly within a zone 2–4 m from the channel walls. Understanding of avoidance and structure oriented movementation exhibited by eels will help advance effective guidance and downstream passage solutions for adults.  相似文献   

基于线粒体DNA Cyt b研究城市化对上海金线侧褶蛙遗传结构的影响     

张伟  谢汉宾  杨刚  王军馥  李必成  王天厚  王小明 《野生动物学报》2021,(2):470-478

城市化在全球范围内快速扩张,已经成为影响物种进化的重要力量。两栖动物的迁移能力较弱,城市化导致两栖类被完全或部分的隔离,丢失更多的遗传多样性。本研究对上海市的金线侧褶蛙(Pelophylax plancyi)的mtDNA Cyt b部分序列进行分析,共扩增出235条序列,获得61个单倍型。研究表明城市区域遗传多样性较低,上海市的金线侧褶蛙分化程度处于中低的水平(Max F_ST=0.296;Min F_ST=0.004),各种群之间遗传分化有限。黄浦江及其支流可能作为水上扩散通道,有助于基因交流,各城市公园之间的遗传分化差异并不显著;而长江阻碍了种群之间的交流,城市公园和郊区,以及岛屿种群之间的遗传分化显著。此外,单倍型网络和系统发育分析表明,上海的金线侧褶蛙并没有对应城市化程度形成相应的单系。  相似文献   

防风固沙草方格铺设机器人通过性研究   总被引：2，自引：1，他引：2  

舒庆  刘晋浩 《农业机械学报》2007,38(7):99-102

在沙漠沙土物理性能试验的基础上，对轮胎与沙土相互作用力进行计算，得到沙漠牵引车在行驶过程中产生的驱动力，进行了纵向铺草机构滚轮压草阻力试验，依据汽车地面力学理论对草方格铺设机器人的通过性进行了研究，结果表明所设计的机器人在沙漠中具有良好的通过性。  相似文献   

我国茸鹿杂交试验研究工作的成就及思考   总被引：10，自引：7，他引：3  

郑兴涛  邴国良 《经济动物学报》1998,2(4):55-60

我国养鹿业近４０年开展了１２种茸鹿的种间和亚种间的８种杂交（系）、２８种组合方式的试验。选育出高产、优质、低耗的茸鹿新品种（系）,对开辟茸鹿杂交育种研究的新领域具有重大的现实意义。  相似文献   

应对胶合板“双反”调查的分析及思考   总被引：1，自引：0，他引：1  

石超  罗岱 《林产工业》2015,42(5)

我国与美国在林产品国际贸易上一直纠纷不断。继2006年美国对我国林产品进行"337"调查、2010年对我国复合地板"反倾销、反补贴"调查之后,2012年,美国几家胶合板企业联合向美商务部DOC递交了关于启动对中国出口美胶合板产品"反倾销、反补贴"调查的报告。中国林产工业协会及涉案企业经过1年多的努力应诉,终于在美国国际贸易委员会(ITC)终裁环节中获得胜利。围绕美国对我国胶合板产品"反倾销、反补贴"调查胜诉案例,全面分析了"双反"调查提出的背景,简述了我国对胶合板"双反"调查的应诉情况,系统总结了应对"双反"胜诉的原因、获得的经验、产生的影响。并对今后面临问题所应采取的措施进行了深入思考。  相似文献   

中国鳗鱼出口面临的技术壁垒与对策   总被引：1，自引：0，他引：1  

赵闰  田倩倩  薛勇臻 《渔业经济研究》2006,(4):30-33

我国是世界上最大的产鳗国,主要出口日本。但自2001年起,日方对鳗鱼制定了较为严格的技术性标准,使我国的鳗鱼出口遭遇到越来越严重的技术性贸易壁垒。如何跨越日本的技术性贸易壁垒,促进我国鳗业出口的健康发展是摆在我们面前的重大课题。文章分析了我国鳗业发展中存在的问题,并提出了相关对策。  相似文献