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321.
Satellite tracking was used to follow the movements of a problematic top-order carnivore, the wild dog (Canis lupus dingo, C. lupus familiaris and their hybrids), in contiguous forested landscapes in south-eastern mainland Australia. Home range sizes of wild dogs were much larger than previously determined using conventional telemetry methods, averaging 10,000 ha with a maximum size of 59,000 ha over approximate 3-month periods. Wild dogs at sites with high abundance of kangaroos, wallabies and rabbits had smaller areas of occupancy than did dogs at sites with low availability of these preys. Despite mostly large home ranges, tracked animals were loyal to publicly-owned tenure and there were few instances where individuals moved large distances on to adjacent private tenure. Instead, movement behaviours of most tracked animals were characterised by repeated short distance forays, often at acute angles from previous locations. Consequently, home ranges were stable and otherwise well defined. Analysis of DNA from our study animals indicated that most individuals were of ‘dingo’ ancestry, but otherwise considered hybrids because of the presence of domestic dog genes. Only two of 24 animals could be considered as ‘pure’ dingo. Contemporary wild dog management demarcates lands where control is or is not undertaken, with the latter notionally acting to ‘conserve’ dingoes. Due to the large scale of movement of animals, existing control efforts likely impact over a greater area than previously suspected. Furthermore, our genetic findings suggest that conservation of dingoes in south-eastern mainland Australia is difficult to achieve. A modified approach to wild dog management is needed, taking account of the extent of range of individual animals and the existing genetic characteristics of populations.  相似文献   
322.
毛竹基腐病综合防治技术的研究   总被引:2,自引:0,他引:2  
报道毛竹基腐病(Arthriniumphaeospermum)综合防治技术的研究结果:(1)40%拌种双和70%甲基托布津可湿性粉剂对病菌的生长有极强的抑制力;(2)通过栽培技术措施培育和留养个大体壮的中期笋,使其快速生长,具有避病的效果;(3)及时剥除已感病竹笋基部的笋箨,有利于病情的控制;(4)一套以栽培措施为基础,化学防治为辅的综合防治技术,在大面积竹林内试验,防治效果达9246%。  相似文献   
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ABSTRACT A new tospovirus species serologically distinct from all other established tospoviruses was found in tomato in Iran. Typical disease symptoms observed include necrotic lesions on the leaves and yellow ring spots on the fruits, hence the name Tomato yellow ring virus (TYRV) was proposed. The S RNA of this virus was cloned and its 3,061 nucleotide long sequence showed features characteristic for tospoviral S RNA segments. The nucleocapsid (N) protein with a predicted Mr of 30.0 kDa showed closest relationship to the N protein of Iris yellow spot virus (74% sequence identity).  相似文献   
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抽提不同处理的野桑蚕各组织总mRNA,利用地高辛标记的野桑蚕CYP305BlVl的cDNA基因作为探针,通过点杂交方法研究野桑蚕CYP305lBl基因的组织表达特异性。实验结果显示,CYP305BlVl基因在氟化物诱导后的野桑蚕中肠、脂肪体、马氏管、体壁中有特异性转录。  相似文献   
327.
Fennec foxes (Vulpes zerda) and meerkats (Suricata suricatta) are considered to be susceptible to canine distemper virus (CDV) infection. Although no definitive clinical cases of natural CDV infections have been reported, mortalities due to CDV have been suspected and are reported in other closely related species. A commercially available monovalent, live, canarypox-vectored CDV vaccine induced neutralizing antibody titers that were maintained for at least a year in both fennec foxes and meerkats.  相似文献   
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Floodplains along large European rivers are diffusely polluted with heavy metals due to emissions in the past. Because of low mobility of heavy metals in floodplain soils and improvements of water quality, these pollutants will remain in place, and can gradually become covered with less contaminated sediments. Bioturbators, especially earthworms, can play an important role in the mixing and surfacing of contaminated substrate. Surfaced substrate can be redistributed by recurrent flooding events, even to areas outside the floodplain. The question remained to what extent bioturbation by small mammals contributes to the redistribution of heavy metals from river sediments in floodplains. Extensive fieldwork on bioturbators such as voles, moles and earthworms and their distribution patterns, as well as on sediment deposition and bioturbation, was conducted at the ‘Afferdensche en Deestsche Waarden’ floodplain over the years 2001–2003. Field data were combined with data of experiments in field enclosures and substrate columns to calculate the amounts of sediment and heavy metals (Zn, Cu, Pb and Cd) redistributed during the floods as well as on an annual basis. Moles and voles surfaced considerable amounts of substrate and heavy metals, but not as much as earthworms which contribute a substantial proportion of the total deposition and redistribution during floods. Although the impact of moles and voles on the redistribution during floods was only locally important, on an annual basis the bioturbation activity of especially moles in floodplains cannot be neglected. The annual amounts of substrate and heavy metals surfaced by all investigated bioturbators were even larger than the total amounts of substrate and heavy metals deposited during floods.  相似文献   
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