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41.
In birds, host experience can modify response to parasites but nothing similar is known for insects. We studied two desert tenebrionid beetles, the subsocial host Parastizopus armaticeps and its obligate and ubiquitous brood-(clepto)parasite Eremostibes opacus, which mimics the hosts odour spectrum. Nearly 10% of host burrows in the field (n=214) remain unparasitised even after introducing E. opacus experimentally (n=22). In discrimination tests, 7% of naive host beetles eject the parasite, showing individual variation in olfactory discrimination ability. To test for effects of prior breeding experience, naive (first time) or experienced (second time) breeders with or without prior parasite contact were confined with E. opacus at breeding onset, their behaviour recorded and parasite number counted on breeding completion. More first- than second-time breeding pairs completely excluded the parasite and second-time breeders with no prior contact with E. opacus had fewer parasites than any others. These pairs increased burrow-guarding dramatically, mostly during early reproduction, this being the best predictor of parasite number. Prolonged guarding, however, must be traded-off against other brood-care behaviours. Hence, it might pay breeding pairs to take the risk of accepting some parasites breeding within their burrow, and we expect this effect will be more pronounced if poor feeding and digging conditions are taken into account. This might explain why apparently 90% of the P. armaticeps breeding burrows in the field contain at least one parasitic E. opacus.Communicated by D. Gwynne 相似文献
42.
Hubert?ChansonEmail author Richard?Brown John?Ferris Ian?Ramsay Kevin?Warburton 《Environmental Fluid Mechanics》2005,5(6):553-575
In natural systems, mixing is driven by turbulence, but current knowledge is limited in estuarine zones where predictions
of contaminant dispersion are often inaccurate. A series of detailed field studies was conducted in a small sub-tropical creek
in eastern Australia. Hydrodynamic, physio-chemical and ecological measurements were conducted simultaneously to assess the
complexity of the estuarine zone, notably the interactions between turbulence and environment. The measurements were typically
performed at high frequency over a tidal cycle. The results provide an original data set to complement long-term monitoring
and a basis for a more detailed study of mixing in sub-tropical systems. Unlike many long-term observations, velocity and
water quality scalars were measured herein with sufficient spatial and temporal resolutions to determine quantities of interest
in the study of turbulence, while ecological indicators were sampled systematically and simultaneously. In particular the
results yielded contrasted outcomes, and the finding impacts on the selection process for key water quality indicators. 相似文献
43.
Stephen F. McCool Jack Utter 《Journal of the American Water Resources Association》1981,17(3):431-437
Allocating river recreation use to commercial and private sectors on white water rivers has been highly controversial. How this process is implemented may affect not only the availability of recreation opportunities to individual users, but may also negatively impact the user's desire to escape from the pressures and stresses of everyday life. In a study of users of Idaho's Middle Fork of the Salmon River, an Even-Pool allotment technique was preferred over others by the commercial, private, and rejectee individuals sampled. A lottery technique for rationing private use permits was preferred by private users and rejectees, while commercial users preferred Advance Reservation. No relationship was found between the users' stress release/escape expectations and their preferences for the different allotment and rationing techniques studies. Such results suggest that river managers may have considerable latitude in selecting allocation techniques that do not adversely affect on-site recreation experiences. 相似文献
44.
湖北省节庆旅游开发研究 总被引:11,自引:0,他引:11
节庆旅游的开发在提高区域知名度、传播区域文化、塑造区域旅游品牌、促进区域对外经济合作、带动区域经济发展方面发挥重要作用。在对节庆旅游概念界定和湖北省节庆旅游概况分析的基础上,从精品打造、市场运作、分工协作、群众参与、营销等方面提出了湖北省节庆旅游开发的策略。 相似文献
45.
Experience sampling methodology and daily diary (ESM/DD) research elicits repeated reports of immediate or very recent experiences from the same sample of people for several days or weeks. Experience sampling and diary methods were almost unheard of in organizational research 15 years ago, but the past decade has seen a rapid rise in their use. These methods are helpful in studying dynamic within‐person processes involving affect, behavior, interpersonal interactions, work events, and other transient workplace phenomena over time. Assessing cross‐level effects of traits or other stable features on within‐person processes and reactivity is also possible with ESM/DD data. We provide an introduction to issues in designing and carrying out an ESM/DD study, including data collection choices and schedules, measures, technology, training and motivation of participants, and analysis of multilevel data. We offer best practice recommendations and refer readers to further resources for additional detail on conducting and analyzing ESM/DD research. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
46.
依据2006—2020年突发环境事件数据,运用统计和个案分析方法,分析了近年来我国突发环境事件的演变规律、总体情况及特点,基于典型案例,探讨了突发环境事件应对的有效模式及成功经验。结果表明:2006—2020年全国共发生突发环境事件6 569起,总体呈下降趋势;2016—2020年发生的重大及以上突发环境事件较2011—2015年下降了69%,趋势明显,说明我国突发环境事件总体上得到了有效防控。然而,事件多发频发的高风险态势并没有根本改变,近年来还呈现出情况复杂、类型多、诱因复杂、公众关注度高等一些新的发展态势。基层环境应急准备扎实、应急指挥体系高效顺畅、预警防控体系健全、科技支撑和物资储运保障有力、信息公开机制健全是妥善应对突发环境事件的成功经验。未来应注重重大环境风险的识别防范,重大及敏感突发环境事件的应急准备和应对、环境应急管理人员能力的培养、环境应急管理体制机制的创新。 相似文献
47.
48.
Past on-site experience was linked to the crowding perceptions and use displacement of 383 on-site visitors to the peri-urban
Danube Floodplains National Park, Austria. Three visitor groups were determined according to their area experience: local
residents from Vienna and rural communities, having the highest level of experience; regional visitors from the city and eastern
Austria; and tourists from Austria and abroad with the lowest degree of experience. Crowding perceptions were significantly
different across the user groups. More than 50% of local residents perceived the national park as crowded, whereas only 27%
of regional visitors and 19% of tourists reported such an evaluation. Even among local residents and regional visitors, respondents
with more on-site experience expressed a greater impression of a crowded park. Differences in crowding evaluations between
local rural and urban residents and between regional rural and urban visitors were not found. For 27% of local residents and
15% of regional visitors, use levels were so unacceptable that they displaced temporally and spatially, whereas use displacement
was relatively irrelevant for tourists. The use displacement strategies involved differ among the three user groups. Management
implications were discussed, taking the specific situation of the small national park on the urban-rural fringe into consideration. 相似文献
49.
湖北省排污权市场的交易频率与交易规模都亟待提高。本文选择全国首家排污权交易中心一嘉兴市排污权储备交易中心作为比较对象,分别从排污权的初始分配、交易制度设计和激励机制等三个方面对两地的具体做法进行了详细的分析比较,最后得出:湖北省在实施排污交易的过程中,初始排污权的分配难以体现公平与效率;集中竞价的交易方式并非当前的最优选择;重平台、忽激励的交易制度设计埋下了市场交易冷清的隐患。最后,提出了相应的改进建议。 相似文献
50.
刘艳霞 《中国环境管理干部学院学报》2014,(4):34-36
秦皇岛市旅游管理体制存在法律、法规不健全,管理体制不明确等问题,因此有必要借鉴日本、英国、泰国先进的旅游管理经验,结合秦皇岛市实际,对秦皇岛市旅游管理体制进行改革,建立全新的"三级两线"旅游管理体制。 相似文献