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991.
A principal role of marine protected areas (MPAs) is to mitigate the decline of biodiversity. A key part of this role is to reduce the effects of fisheries on bycatch of vulnerable species. Bycatch can have an impact on species by reducing population sizes, and an ecosystem-level impact through the significant removal of biomass and subsequent trophic changes. In this regard, it is crucial to refine methods for quantifying interactions between fisheries and bycatch species, and to manage these interactions spatially. A new method is presented for quantifying interactions between fisheries and bycatch species at high spatial and temporal resolutions. Temporally explicit species distribution models are used to examine temporal dynamics of fisheries and bycatch. This method is applied to Australia’s Eastern Tuna and Billfish Fishery to estimate interactions with seven principal bycatch species. The ability of MPAs to reduce bycatch is evaluated, and considerations are outlined for the spatial management of fishery-bycatch species interactions. Australia’s Commonwealth Marine Reserve Network had a minimal impact on bycatch reduction under both the 2012 proclaimed and the 2015 panel-recommended zonings. These results highlight the need for threats to marine biodiversity to be incorporated directly into design of MPAs, and for close scrutiny of assumptions that threats will be incidentally abated after MPAs have been proclaimed, or that off-reserve mechanisms will compensate for inadequacies of MPAs.  相似文献   
992.
Michael Staab 《ZooKeys》2015,(516):137-155
Aenictus is the most species-rich genus of army ants in the subfamily Dorylinae and one of the most species rich ant genera in China and the world. In this paper, a new species of the Aenictus ceylonicus group, Aenictus hoelldobleri sp. n., is described and illustrated based on the worker caste. The new species occurs in the subtropical forests of south-east China and is morphologically most similar to Aenictus henanensis Li & Wang, 2005 and Aenictus wudangshanensis Wang, 2006. Aenictus hoelldobleri sp. n. can be distinguished from both species by the shape of the subpetiolar process. The new species also resembles Aenictus lifuiae Terayama 1984 and Aenictus thailandianus Terayama & Kubota, 1993 but clearly differs in various features of the cuticular sculpture. A key to the Chinese species of the Aenictus ceylonicus group based on the worker caste is provided, which may help to reassess and clarify the taxonomic status of the abundant Chinese records of the true Aenictus ceylonicus (Mayr, 1866), a species which almost certainly does not occur in China. Several new locality records are given, among them the first record of Aenictus watanasiti Jaitrong & Yamane, 2013 from China.  相似文献   
993.
Phosphorus speciation in three submerged macrophytes species, Chara fibrosa Agardh ex Bruzelius, Najas marina Linnaeus and Vallisneria gigantea Graebner, and the implications for phosphorus nutrient cycling in an aquatic ecosystem were studied, using sequential phosphorus fractionations. The results showed that C.␣fibrosa had a far higher residual ash and calcium content compared with the two angiosperm species, but lower total phosphorus content. Two different fractionation methods for phosphorus showed that the bioavailable water-soluble phosphorus (H2O-P) and ammonium chloride extractable phosphorus (NH4Cl-P) of the extractions used represented the major part of total plant phosphorus in the two angiosperm species, while organic phosphorus (NaOH-P) represented a relatively large fraction in C. fibrosa. In this species, about 12–15% of total plant phosphorus was calcium-bound phosphorus (HCl-P), occurring as co-precipitation with calcite encrustation, but this fraction was negligible in the two angiosperm species, i.e. less than 1%. The redox-insensitive forms of HCl-P are considered less bioavailable and not affected by anoxic conditions of bottom sediment, thus have potential as a phosphorus nutrient sink in aquatic ecosystems.  相似文献   
994.
通过野外考察和资料整理,对《国家重点野生保护植物名录(第一批)》中维管植物在滇东南和滇西北的空间分布及其与保护区设置的相关性进行统计和分析。结果表明:1、滇东南有107种保护植物,占云南分布(144种)的74.31%;滇西北53种,占云南省的36.81%;2、滇东南和滇西北保护植物种类垂直分布均呈单峰曲线,滇东南集中分布在海拔1008m附近(RSE=0.9919),滇西北主要在2 360 m附近(RNW=0.9656);3、县级水平的自然保护区设置权重与国家I级(Pearson指数,rI=0.724)和Ⅱ级(rⅡ=0.643)保护植物种类在滇东南均呈极显著的正相关性(P0.01),而在滇西北相关性(rI=0.464;rⅡ=0.410)差异均不显著(P0.05)。滇东南保护植物较滇西北丰富,滇东南保护区设置较滇西北更有利于对保护植物的有效保护。  相似文献   
995.
土地承载力是土地管理和可持续利用的重要研究领域之一,城乡建设用地是土地利用类型的重要组成部分,其结构与布局是否合理对土地可持续利用至关重要.本研究以环鄱阳湖城市群为研究区,进行城乡建设用地开发适宜性评价,核算城乡建设用地可承载临界值,计算可承载城乡建设用地丰度,并与现状城乡建设用地进行空间格局匹配性分析,得到研究区各个县(市、区)的剩余开发强度和空间匹配度.结果表明: 研究区城乡建设用地开发适宜性评价结果等级中,最适宜区、较适宜区、较不适宜区和不适宜区面积分别为3130.62、2477.29、867.03和29509.14 km2.研究区城乡建设用地可承载临界值(可开发强度)为16.6%,各个县(市、区)的值在7.7%~100%,各县(市、区)可承载城乡建设用地丰度在0.15~1.30.研究区剩余开发强度为12.3%,空间匹配度为0.76;各个县(市、区)剩余开发强度在4.9%~53.5%,空间匹配度在0.11~1.00,地区差异较大.此研究有助于明确现状开发状态与合理开发状态之间的关系,可为城乡建设用地的精细化管理、制定空间格局优化调控政策提供依据.  相似文献   
996.
There are sevenlagoons onthe east coast of Korea,including Kyeongpo Lake,Hyang Lake,Mae Lake,Chung-cho Lake,Yeoungrang Lake,Songji Lake and HwajinpoLake.They are all originally natural and brackish waterlakes.Therefore,these lakes are not only historically veryimportant but also have high values for geological,andecological sciences.Natural lakes like lagoons are different from man-made lakes.That is,water level in natural lakes is almostconstant,cline by waterside is not much,and wet la…  相似文献   
997.
Chen JY  Zhou LZ  Zhou B  Xu RX  Zhu WZ  Xu WB 《动物学研究》2011,32(5):540-548
安徽沿江浅水型通江湖泊湿地是东亚-澳大利亚迁徙水鸟的重要越冬地和停歇地。近年来,高强度的渔业养殖使湿地严重退化,对越冬水鸟构成威胁。为了解湿地变化对越冬迁徙水鸟的影响,2007年11-2008年4月和2008年11月-2009年4月,对安徽菜子湖和升金湖11个样带内越冬水鸟的种类、数量及空间分布进行了调查,并分析了湖泊渔业模式对水鸟分布的影响。两个湖泊共统计到越冬水鸟7目12科43种。其中,菜子湖群38种,密度为8.2ind./hm2;升金湖42种,密度为3.5ind./hm2,优势种为鸿雁(Anser cygnoides)、豆雁(Anser fabalis)、小天鹅(Cygnus columbianus)和黑腹滨鹬(Calidris alpina)。越冬水鸟种类和数量在12月底-次年1月上旬达到最大值,但不同类型越冬群最大数量出现的具体时期有所不同。根据水鸟组成的聚类分析,可将水鸟栖息地分为三组。水鸟的分布与渔业模式有关,在自然捕捞区,鹤类、雁鸭类和鸻鹬类密度较大,在围网养殖区密度较小,而鹭类的密度在各湖区变化都较小。本研究结果提示,发展可持续渔业对于长江中下游浅水湖泊湿地越冬水鸟资源的保护具有重要意义。  相似文献   
998.
对石门台自然保护区鸟类组成、鸟类区系和鸟类物种多样性进行了研究.结果表明:该保护区有鸟类208种,隶属16目41科,其中国家一级重点保护鸟类有2种,国家二级重点保护鸟类有25种.在该保护区有分布的208种鸟类中,属留鸟的有156种,属冬候鸟的有 44种,属夏候鸟的有8种.根据中国动物区系的区划,石门台自然保护区分布的鸟类属东洋界物种的有136种,属古北界物种的有43种,属广布种的有29种.本文还分析和研究了石门台自然保护区鸟类区系特征、鸟类生态分布群和经济鸟类等方面的内容.  相似文献   
999.
In this study, the feeding behaviour of the non‐native invasive predatory fishes largemouth bass Micropterus salmoides and bluegill Lepomis macrochirus was studied in the Ezura River, a northern tributary of Lake Biwa, Japan. Prey composition was estimated based on visual examination of stomach contents and faecal DNA analysis to determine feeding habits of these predatory fishes. Stomach content analysis showed that native fishes (e.g. ayu Plecoglossus altivelis and gobies Rhinogobius spp.) and shrimps (e.g. Palaemon paucidens) were the major prey items for M. salmoides, while snails, larval Chironomidae and submerged macrophytes were the dominant prey items of L. macrochirus. Micropterus salmoides tended to select larger fish in the case of crucian carp Carassius spp., but smaller fishes in the case of P. altivelis and Rhinogobius spp. Faecal DNA analyses revealed prey compositions similar to those identified in predator stomach contents, and identified additional prey species not detected in stomach content inspection. This study demonstrated that both stomach content inspection and DNA‐based analysis bear several inherent shortcomings and advantages. The former method is straightforward, although identification of species can be inaccurate or impossible, whereas the latter method allows for accurate species identification, but cannot distinguish prey size or stage. Hence, integration of morphology‐based and DNA‐based methods can provide more reliable estimates of foraging habits of predatory fishes.  相似文献   
1000.
在野外调查及查阅相关资料的基础上,对广东从化陈禾洞省级自然保护区植物区系进行研究。结果表明:(1)该区植物资源丰富,共有野生维管植物193科627属1139种(包括种下等级)。其中,蕨类植物36科66属119种,裸子植物7科8属9种,被子植物150科528属1011种(双子叶植物130科417属838种,单子叶植物20科111属173种)。(2)该区种子植物科、属优势现象明显,以菊科Asteraceae、禾本科Poaceae及茜草科Rubiaceae为主。在科属的组成上较为分散,主要以少寡种的科、属为主,分别占67.88%、91.7%。(3)该区蕨类植物在属的组成上也较为分散,以5个种以下的属为主,占比为93.94%。(4)该区植物区系成分复杂,在科级水平上,种子植物有8个分布区类型及5个变型,热带分布类型成分有80个科,占总科数的50.96%,而蕨类植物有5个分布区类型,热带成分的科有23个,占蕨类总科数的63.89%;在属级水平上,种子植物有13个分布区类型及16个变型,热带成分有365属,占总属数的68.10%,而蕨类植物有7个类型及1个变型,热带分布类型成分有40属,占蕨类植物总属数的60.61%。  相似文献   
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