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71.
Sharon A. Gill Maarten J. Vonhof Bridget J. M. Stutchbury Eugene S. Morton James S. Quinn 《Behavioral ecology and sociobiology》2005,57(6):557-565
There are few empirical tests of the acoustic mate-guarding hypothesis for the function of duetting in birds. This hypothesis states that when females are fertile, males initiate many songs or answer most of their mates solo songs to form duets and repel rival males seeking extra-pair copulations. We tested the hypothesis by comparing song initiation and answer rates of males and females in socially monogamous buff-breasted wrens (Throthorus leucotis) during pre-fertile and fertile periods. During pre-fertile periods, males often sang for short periods before being answered by their mates, yet first duets were formed earlier relative to dawn and more duets were given during the dawn chorus on pre-fertile than fertile mornings. Males initiated more songs during pre-fertile than fertile periods, whereas there was no difference between stages in female song initiation rates. The proportion of songs answered by individuals of both sexes did not differ between breeding stages. Other mate-guarding behaviours, such as frequent copulation and maintaining close proximity to mates when fertile, did not appear to be important in this species, as no copulations were observed and there was no difference in the time pairs spent in close proximity when females were fertile or not. Parentage analysis revealed that only 3% of 31 broods had young that were likely the result of extra-pair paternity. These findings do not support the acoustic mate-guarding hypothesis, and suggest that the low rate of extra-pair paternity in buff-breasted wrens was maintained without the use of acoustic or traditional paternity guards.Communicated by R. Gibson 相似文献
72.
Pedro D. Fernández Tobias Kuemmerle Matthias Baumann H. Ricardo Grau José A. Nasca Alejandro Radrizzani 《Journal of Land Use Science》2020,15(1):52-68
ABSTRACTImpacts of cattle production vary among different production systems, but data on their distribution is scarce for most world regions. In this work, we combine datasets on cattle vaccination locations and land cover in a regression framework to define and map major cattle production systems in the Argentinean Dry Chaco. We also explore how cattle occurrence relates to spatial determinants. Results indicate that the region harbors about 5.5 million heads. Cattle density was mainly described by the share of pasture (69.9%), cropland (28.1%) and aridity (23.8%). We identified 12-major cattle production systems: six cow-calf, three whole-cycle, and three fattening systems. Of these, four systems had high woodland cover (>85%). Data generated is available in a website. Understanding the distribution of cattle production systems is important to assess the environmental impacts of beef production at broad scales. Integrating vaccination data with land-cover information provides a promising avenue to identify livestock systems. 相似文献
73.
Anne?CharmantierEmail author Philippe?Perret 《Behavioral ecology and sociobiology》2004,56(4):360-365
We tested the effect of manipulation of breeding density on the occurrence of extra-pair paternity in a blue tit (Parus caeruleus) population during two consecutive years. In a homogeneous oak forest, nest-box manipulation provided a high density plot (plot A, 1.10 and 1.32 pairs/ha) and a low density plot (plot B, 0.43 and 0.46 pairs/ha). Microsatellite analysis on 91 broods revealed a higher proportion of extra-pair paternity in broods in plot A (mean of 17.2%) than in plot B (mean of 11.4%). A correlative approach showed that the proportion of extra-pair young in broods was affected by the number of breeding neighbours within 100 m around the nest-box, by the distance to the nearest breeding neighbour and by an additional plot effect. However, the nearest neighbours accounted for only 39.3% of extra-pair paternities and distance to extra-pair fathers was significantly higher than the nearest neighbour distance in both plots. This implies that the effect of density on the occurrence of extra-pair paternities is associated with active female choice to enhance the brood fitness. Although there were more extra-pair young in broods when density was high, the number of extra-pair fathers did not increase and stayed close to one. We suggest that density increases the cost of mate guarding by males, thereby increasing the possibility for females to solicit extra-pair paternities to the cuckolding male they have chosen. Finally, we discuss why correlatives approaches do not always show evidence for an effect of breeding density on extra-pair paternity occurrence.Communicated by M. Soler 相似文献
74.
简述了近十几年来原子吸收光谱在我国石油化学工业领域的应用及进展,全文分原油及其加工产品,化工物品,催化剂添加剂等几类样品阐述。 相似文献
75.
水泥行业为粉尘重污染行业 ,其粉尘治理的好坏 ,反映了其环境保护水平的高低。本文将结合目前水泥工业生产工艺及技术装备水平 ,从窑系统除尘器选择与使用到环境管理多个方面 ,分析提高其环境保护水平的途径 相似文献
76.
Paul Scott Paul Brown Julia Verne Jody James Alistair Gordon Joyshri Sarangi Jonathan A. C. Sterne 《Environmental geochemistry and health》2009,31(2):297-308
This ecological study aimed, through the analysis of 1,146 wards in the South West of England (1998–2002), firstly, to examine
whether chemical incidents and public casualties are more likely near complex industry (emissions to land, air or water: Integrated
Pollution Control industry, IPC) or industry with emissions to air only (Local Air Pollution Control industry, LAPC). Secondly,
the study examined whether industry, incidents and casualties are found close to deprivation. Social inequalities were examined
across quintiles of wards. Fifty-two wards (4.5%) contained an IPC industry and 712 (62.1%) an LAPC. Incidents occurred in
132 wards (11.5%), with casualties in 59 (5.1%). Chemical incidents occurred more frequently in wards with LAPC (152, IPC
20); the same was true of casualties (211, 12). With each additional LAPC site in a ward, the risk of an incident rose by
22% (95% confidence interval [CI] 8–38%), suggesting a dose–response relationship. No clear social inequalities were found.
In the South West of England, the public are more likely to be affected by an incident occurring at a simple LAPC site rather
than a complex IPC site. This has implications for emergency planning which, at present, focusses most attention on the larger,
more complex IPC sites. 相似文献
77.
随着全球经济一体化步伐的加快,中国的化工企业已呈现各种化工园区集聚发展的态势。化工园区作为地区化工行业集聚区域,也是一个地区工业经济发展的重要载体,已逐渐成为推动区域经济快速增长的重要支撑。本文分析了国内外先进化工园区管理模式及经验,总结了目前国内化工园区管理中存在的问题,通过借鉴国内外先进化工园区管理模式及成功经验,分析提出解决化工园区环境管理问题的建议,以期为改善园区管理现状、促进化工园区科学发展提供理论依据。 相似文献
78.
我国环保产业研究现状分析——基于宏观视角的文献述评 总被引:1,自引:0,他引:1
通过文献研究法,基于宏观视角对我国环保产业研究成果进行梳理。当前,我国的环保产业研究成果初具规模,研究重点在于环保产业的现状分析、问题探讨以及对策研究,包括环保产业各主体间博弈均衡、环保产业的技术支持、投融资机制等内容。未来环保产业研究应注意环保产业竞争力的科学评价、环保产业主体间的良性互动及其合力的达成以及环保技术评价和兑现。 相似文献
79.
在收集和分析对生态工业发展研究的文献基础上,将影响生态化工产业发展的因素归纳为3大因素:直接因素、间接因素和机制性因素,6个二级指标,分别是自然因素、经济因素、技术因素、产业因素、社会因素、政策法规,同时针对全国第一化工大省山东省不同类型、不同地域的11家化工企业进行了实地调研,并对问卷调研数据进行了基于SPSS软件的克朗巴哈α系数的信度分析以及主成分分析,结果表明问卷具有良好的信度,并按各二级指标中所含因素的重要程度确定了影响生态化工产业发展的12个主要因素,在此基础上提出了化工产业生态化发展的建议,为化工产业生态化建设提供相应的理论支撑。 相似文献
80.
Survival is one of the most central population measures when the effects of the pollution are studied in natural bird populations. However, only few studies have actually measured rigorous survival estimates on adult birds. In recent years there has been a methodological advance in survival analyses by mark-recapture models. We modelled local survival (including mortality and emigration) with the program MARK in a population of a small insectivorous passerine bird, the pied flycatcher (Ficedula hypoleuca), around a point source of heavy metals. The local survival of females in the polluted area was about 50% lower than in the other areas. Males, however, survived relatively well in the heavily polluted area, but showed somewhat lower survival in the moderately polluted area. Different pollution effects between two sexes might be due to pollution-related differences in reproductive effort in females and males, and/or more intensive uptake of heavy metals by laying females. 相似文献