Modeling large-scale winter recreation terrain selection with implications for recreation management and wildlife     

《Applied geography (Sevenoaks, England)》2017

Winter recreation is a rapidly growing activity, and advances in technology make it possible for increasing numbers of people to access remote backcountry terrain. Increased winter recreation may lead to more frequent conflict between recreationists, as well as greater potential disturbance to wildlife. To better understand the environmental characteristics favored by winter recreationists, and thus predict areas of potential conflict or disturbance, we modeled terrain selection of motorized and non-motorized recreationists, including snowmobile, backcountry ski, and snowmobile-assisted hybrid ski. We used sports recorder Global Positioning System (GPS) devices carried by recreationists at two study areas in Colorado, USA, (Vail Pass and the San Juan Mountains), to record detailed tracks of each recreation type. For each recreation activity, we modeled selection of remotely-sensed environmental characteristics, including topography, vegetation, climate, and road access. We then created spatial maps depicting areas that recreation activities were predicted to select and combined these maps to show areas of potential ecological disturbance or interpersonal conflict between motorized and non-motorized activities. Model results indicate that motorized and non-motorized activities select different environmental characteristics, while still exhibiting some similarities, such as selection for ease of access, reflected in proximity to highways and densities of open forest roads. Areas predicted to have only motorized recreation were more likely to occur further from highways, with greater forest road densities, lower canopy cover, and smoother, less steep terrain, while areas with only non-motorized recreation were closer to highways, with lower forest road densities, more canopy cover and steeper terrain. Our work provides spatially detailed insights into terrain characteristics favored by recreationists, allowing managers to maintain winter recreation opportunities while reducing interpersonal conflict or ecological impacts to sensitive wildlife.  相似文献   

Role of risk assessment in fish health policy and management     

Stephen  C. 《ICES Journal of Marine Science》2001,58(2):374-379

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海洋中倾废物的声学测量和跟踪     

孙瀛  聊洪荣  李伟  李岩辉 《台湾海峡》1995,(4)

本文较详细地讨论了海洋声学体散射理论和海水中悬浮物扩散理论。对比DFS－2100型声学测量系统和TCL－204型双频探鱼声纳的技术性能之后，对国产TKL－204声学系统作了重大改进，使其适于对海洋倾废物进行测量和跟踪。现场实验结果表明，经过改进后的系统是成功的，同时也证明了文中所用的扩散理论对分析海洋中悬浮物的扩散规律是有用的。  相似文献   

山东省大、中型水库鲢、鳙的生长与环境条件的关系     

任敬明  李德尚  周春生 《中国海洋大学学报(自然科学版)》1993,(4)

根据1989年的调查资料,研究了山东省20座大、中型水库鲢、鳙的生长与环境条件的关系。将进水量、集雨区土壤肥力、总氮、总磷、硬度、电导率、化学耗氧量、浮游植物生物量、浮游动物生物量等9项标志水域鱼产力的环境条件,分成基础条件(指前二项)、化学条件和生物条件三个层次分别考查其与鲢、鳙的生长关系。提出的这三个层次都对生长有显著影响,达到或接近于强相关。通过逐步回归得出的复回归模式则更表明生长与这些条件的相关高度显著。指出在像当前山东省大多数水库这样,鱼的密度显著小的情况下,鱼的生长情况可以作为概略评价水域鱼产力的一个相对指标。  相似文献   

The distribution and population dynamics of O-group plaice (Pleuronectes platessa L.) on nursery grounds in the Firth of Forth     

M. G. Poxton  N. A. Nasir 《Estuarine, Coastal and Shelf Science》1985,21(6):845-857

Midsummer (1 August) population estimates of about 2 million O-group plaice (Pleuronectes platessa L.) were derived for sandy bays around the Firth of Forth in 1979–1980. This is an order of magnitude less than similar estimates made for the Clyde Sea Area in 1973–1974. Autumn population estimates of 0·4–1·0 million fish were comparable to estimates by the Ministry of Agriculture, Fisheries and Food for the area between the Scottish border and Flamborough Head (2·3 million for 1970 and 1973) which represented 4·8% (1973) to 5·3% (1970) of the total number of O-group fish on the English east coast.Largo Bay was the most important nursery area holding 25% of the total population. It is particularly well situated to receive newly metamorphosed plaice carried in water currents along the north side of the Forth from the spawning ground off Fife Ness. Plaice in the Forth are mainly distributed on fine to medium sandy beaches (186–480 μm), the mean number per haul in midsummer (D) being correlated with the median diameter (m.d. in μm) of the low water sediments by the equation: D=−45·7666+0·2327 m.d. (n=11,r=0·68,P<0·02 but>0·01).The shallow inshore water in sandy bays in the outer Firth was well mixed and more marine than estuarine (27·7–35·0‰). The correlation coefficient between fish density and water temperature was low, while that with salinity (S‰) was: D=6·1618+0·2238S (n=23,r=0·62,P<0·005).Regression analysis demonstrated that the relationship between the instantaneous mortality rate (Z) and the initial population density (D_p) was: Z×100=0·7480+0·0546d_p (n=12,r=0·87,P<0·001).The mean mortality rate for the O-group plaice in the Forth nursery areas was 53% month⁻¹.  相似文献   

海洋鱼类育苗期配合饵料代替活饵的研究进展     

王素芬  王安利  胡俊荣 《海洋通报》2003,22(3):89-96

综述了近年来在海水鱼类育苗中，利用配合词料代替活饵的研究状况，以及海水鱼类幼体消化酶与微胶囊饵科吸收和利用的关系；同时对海水鱼类幼体微粒子饵科的制备方法进行了探讨，以期为研制海洋鱼类育苗期的配合饵科提供参考。  相似文献   

Time-series data for a selection of forty fish species caught during the International Bottom Trawl Survey     

Heessen  Henk J. L. 《ICES Journal of Marine Science》1996,53(6):1079-1084

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南海北部三种金线鱼属鱼类BHC,DDT残留研究   总被引：4，自引：0，他引：4  

甘居利  贾晓平  李纯厚  林钦 《海洋学报》2007,29(5):95-101

为探讨六六六(BHC)、滴滴涕(DDT)对远岸海域渔业资源和水产品质量的影响,用气相色谱法测定了南海北部陆架海域3种金线鱼属(Nemipterus)鱼类肌肉内和其中深水金线鱼(N.bathybius)5种组织内的BHC、DDT含量.结果显示,研究海域鱼肉中BHC和DDT含量分别为0.04~0.89(平均0.26)μg/kg(湿重)、0.71~8.0(平均3.1)μg/kg(湿重),均低于亚太地区部分近岸海洋鱼类的残留水平,并低于国内外水产品安全限量,呈广东海域高于台湾浅滩的区域分布,但在不同鱼种之间、离岸远近的鱼类之间BHC、DDT含量差异不明显(p>0.10).深水金线鱼体内农药含量在肝组织中较高,在肌肉内居中,在鳃丝中较低,BHC含量由高到底的顺序为:肝脏、腹肌、背肌、肠、皮、鳃丝,DDT含量由高到底的顺序为:肝脏、腹肌、背肌、皮≈肠、鳃丝,不同组织中pp-DDT,op-DDT含量与脂肪含量较显著地正相关(p<0.05).  相似文献   

渤、黄海4 种小型鱼类摄食排空率的研究   总被引：9，自引：0，他引：9  

孙耀  刘勇  张波  唐启升 《海洋与湖沼》2002,33(6):679-684

采用现场或实验室模拟法测定了体重分别为 ( 6 72± 1 95 )g、( 2 0 3± 0 46)g、( 0 68±0 1 5 )g和 ( 2 1 8± 0 60 )g的渤、黄海 4种小型鱼类斑、赤鼻棱、玉筋鱼和小鳞的摄食排空率 ;并比较了线性、指数和平方根 3种常用数学模型对其排空曲线的拟合程度。统计检验结果表明 ,4种实验鱼类的摄食排空曲线均可较好地用 3种数学模型进行拟合 (df=7— 1 0 ,r2 =0 785 2— 0 9787,P <0 0 1 ) ;如果以r2 为指标评价 ,指数模型对玉筋鱼和小鳞的拟合程度较高 ,而平方根和直线模型较适于描述赤鼻棱和斑 ;综合评价结果则进一步表明 ,指数模型最适于定量描述 4种鱼类的摄食排空曲线 ,平方根模型次之 ,直线模型较差。 4种鱼类摄食排空率有较大差异 ,从排空起始至胃含物的 5 % ,用时范围在 1 1 64— 2 4 70h之间 ;本实验条件下 ,4种鱼类摄食排空率顺序为 :玉筋鱼 >赤鼻棱 >斑 >小鳞。引起不同鱼类摄食排空率显著差异的原因可能与胃结构有关。  相似文献   

Evaluation of video and acoustic index methods for assessing reef-fish populations   总被引：1，自引：0，他引：1  

Gledhill  Christopher T.; Lyczkowski-Shultz  Joanne; Rademacher  Kevin; Kargard  Eva; Crist  Gregg; Grace  Mark A. 《ICES Journal of Marine Science》1996,53(2):483-485

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