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Harbour seal (Phoca vitulina) abundance within the Firth of Tay and Eden Estuary,Scotland: recent trends and extrapolation to extinction 下载免费PDF全文
Nora Hanson Dave Thompson Callan Duck John Baxter Mike Lonergan 《水产资源保护:海洋与淡水生态系统》2017,27(1):268-281
- Aerial surveys have detected alarming declines in counts of harbour seals in several regions across Scotland.
- Demographic data and simple models were used to examine the recent decline in the numbers of harbour seals counted in one population within a Special Area of Conservation (SAC) on the east coast of Scotland. The models suggest that the continuation of current trends would result in the species effectively disappearing from this area within the next 20 years.
- While the cause of the decline is unknown, it must be reducing adult survival because the high rate of decline cannot be wholly accounted for by changes in other demographic parameters.
- Recovery of the population to the abundance recorded at the time the SAC was designated (2005) is likely to take at least 40 years, even if the cause of the decline is immediately identified and removed.
- The models suggest that partial removal of the cause can have only limited benefits to population recovery, and there are unlikely to be any long‐term benefits from introducing or reintroducing additional individuals while the underlying problem persists. Therefore, if the population of harbour seals in this area is to recover it is essential that the sources of the increased mortality are identified and measures are put in place to manage these.
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[目的]采用响应面法优化啤酒糟中水溶性膳食纤维的提取工艺,以期提高啤酒糟的综合利用价值。[方法]采用酶法提取啤酒糟中水溶性膳食纤维。在单因素试验基础上,以温度、纤维素酶量、固液比3个因素为自变量,水溶性膳食纤维得率为响应值,进行响应面分析,确定最佳工艺参数。[结果]啤酒糟中水溶性膳食纤维最佳提取条件:温度为50.8℃、纤维素酶量为6.7%、固液比(g∶m L)为1∶14。当满足最佳提取条件时,验证值为5.16%。根据最佳提取条件进行验证试验,水溶性膳食纤维的实际得率为5.09%,相对误差为1.36%。[结论]酶法提取提高了水溶性膳食纤维得率,且操作简单、可重复性强,适用于啤酒糟中水溶性膳食纤维的提取。 相似文献
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Annalisa Azzola Giorgio Bavestrello Marco Bertolino Carlo Nike Bianchi Marzia Bo Francesco Enrichetti Carla Morri Alice Oprandi Margherita Toma Monica Montefalcone 《水产资源保护:海洋与淡水生态系统》2021,31(4):737-747
- Detailed knowledge about the distribution of species in need of protection is required for the management of Marine Protected Areas, a major tool to reduce marine biodiversity loss. Such knowledge is deficient for most marine invertebrates.
- Axinella polypoides is a marine sponge included on the list of protected species by the Barcelona Convention (1976) and the Bern Convention (1987). This large and erect species has an important ecological role in habitat forming and benthic–pelagic coupling.
- Bathymetrical, geographical and ecological data over the last 60 years were collated from publications and reports, together with new surveys to assess the distribution and protection status in Liguria of A. polypoides. It identified a more widespread distribution than previously thought, which points at a general need for dedicated investigations on the occurrence of species that require protection.
- Bathymetrical distribution was trimodal, with peaks corresponding to different geomorphological settings: coastal cliff bases (around 38 m depth), inner shelf shoals (52 m) and rocks amidst coarse sediment on the outer shelf (79 m). Density was significantly greater at the shallowest depths. The species was mostly found in the coralligenous biocoenosis, in association with other characteristic species or forming a monospecific facies.
- On (sub)vertical cliffs, A. polypoides often exhibited an unusual cane shape, rather than the typical bushy morphology, thus causing confusion with the congeneric A. cannabina, a more southern species. Records of the latter in the Ligurian Sea therefore need confirmation.
- Only a minority (22.6%) of A. polypoides records were in Marine Protected Areas, the remainder being located in areas with no current environmental protection plans in place. While the occurrence of this species in MPAs remained stable over the decades, the only quantitative historical data available indicated that populations in non-protected areas were declining owing to anthropogenic impacts (fishing and anchoring).
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玉米机械化子粒收获是中国玉米未来的发展方向。为了探讨不同玉米自交系材料的配合力及其组配杂交组合的机械化粒收质量影响程度,本研究以7个美国自交系材料作母本,‘新01A3’的5个改良系作父本,采用不完全双列杂交,以组配成的35个玉米杂交组合为试验材料,机械化子粒收获后,测定产量和子粒含水率,计算杂质率、破碎率和田间损失率,并对产量进行配合力分析。结果表明,‘XL2’产量的一般配合力(GCA)最高。5个父本自交系中,‘新A389’产量的一般配合力最高,其次为‘新69’。‘XL6×新69’的产量特殊配合力(SCA)最高,其次为‘XL7×新3764’。对各项性状指标进行相关性分析,结果显示,子粒含水率与破碎率之间存在显著正相关。35个杂交组合中,32个玉米杂交组合的产量与邻近对照相比增幅超过5%,且所有杂交组合的子粒含水率均低于28.0%,均适宜机械化子粒收获。今后应加强对高配合力自交系‘XL2’、‘XL5’和‘新A389’、‘新69’的利用。 相似文献
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在盆栽条件下,研究了啤酒糟和白酒糟对连作平邑甜茶幼苗生长及其连作土壤中微生物的影响。结果表明,连作土壤添加酒糟可显著提高平邑甜茶幼苗株高、干样质量、鲜样质量等生物量指标。添加酒糟后土壤中细菌、真菌数量与连作土对照相比也有明显提升。通过聚类分析、主成成分分析和多样性分析发现,加入酒糟后土壤中微生物群落结构发生明显变化,且不同酒糟类型和不同酒糟处理方式造成微生物的群落结构不同;由于酒糟自身携带及灭菌酒糟在土壤中滋生的微生物,促使土壤中优势种群的出现,改变了土壤中微生物群落的多样性指数和丰富度指数。对土壤中的层出镰孢菌(Fusarium proliferatum)进行实时荧光定量分析显示,与连作土壤对照中的层出镰孢菌基因拷贝数相比,啤酒糟、白酒糟、灭菌啤酒糟和灭菌白酒糟处理分别降低了39.1%、58.1%、20.9%和39.2%,酒糟灭菌后减弱了对有害菌层出镰孢菌的抑制作用。综上,苹果连作土壤中加入酒糟后,改变了土壤中微生物的群落结构,降低了有害真菌的数量,减轻了苹果连作障碍现象,其中白酒糟效果更好。 相似文献
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园林道路平曲线的施工放线是一项比较繁难的工作.当园林绿地中的园路紧靠建筑物、水体等特殊环境,园路平曲线的交点和圆心都被遮挡或无法定位时,常规的园路平曲线放线方法有的不适用,有的则太复杂.针对这种特殊园路平曲线的放线工作情况,根据在工作中的探索,介绍了一种新颖的、简便的园路平曲线施工放线方法,并对此方法的操作步骤和适用范围及注意事项进行了详细的说明,旨在利用简单的工具准确高效地完成施工放线工作. 相似文献
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Brewer's spent grain (BSG), the most abundant brewing by-product, has hidden and underexploited nutritional potential. In order to valorize BSG, the effects of three commercial xylanases and a peptidase on water unextractable arabinoxylans (WUAX) were studied. Comparing all treatments, higher addition of xylanase resulted in an increase in water extractable arabinoxylans (WEAX). In the most efficient treatment, xylanase alone was able to solubilise 23.7% of WUAX, while the peptidase showed no effect. However, when added together with xylanase, peptidase increased the solubilisation of WUAX up to 1.6 folds. A positive correlation between particle size reduction and solubilisation of WUAX was also proved through milling BSG. These results suggest that access to xylan backbone increases with proteolytic activities, proving a synergistic effect of these specific enzymes. Therefore, if properly treated before being added as ingredient, BSG could add health functionalities to foodstuff while reducing the environmental impact of brewing industries. 相似文献