Female reproductive success and nest predation in polyterritorial wood warblers (Phylloscopus sibilatrix)

Summary Polyterritorial polygyny in passerine birds, i.e., when already-paired males attract females in secondary territories, has been explained by male deception. Secondary females are assumed to make a poor choice, because they lack information about males' pairing status. To date, the deception hypothesis has focused mainly on the hole-nesting pied flycatcher. In this study of polyterritorial wood warblers, an open-nesting species, secondary females did not differ in number of fledged young compared with females of monogamous males, and they fledged even more young than primary females. Nest predation influenced the allocation of paternal care. Almost half of the secondary females had exclusive male assistance because nests of primary females were preyed upon.     

基本原理,概念及评估办法

引言 人们普遍认为,全球气候变暖在北极将进一步放大,由于平流层臭氧修复的可能延误,紫外线B(UV-B)辐射可能继续增加,北极环境及其居民可能特别易受这类环境变化的影响.上述共识促进了对气候变化影响的国际评估工作.北极气候影响评估(ACIA)是一项为时4年的研究,结果出版了一篇重要的科研报告[1]并产生了其他的成果.在本文以及本期Ambio专刊下面的文章中,我们提供了报告中针对北极陆地生态系统(从树线群落交错带到极地荒漠)的部分研究成果.     

Spatio-temporal change of ecosystem services as a key to understand natural resource utilization in Southern Chile

Regional Environmental Change - The understanding of how ecosystem services are distributed across the landscape and their change over time provides key information to manage multi-functional...     

Persistent organochlorine pollutants in children working at a waste-disposal site and in young females with high fish consumption in Managua, Nicaragua

The aim of this study was to assess persistent organochlorine pollutant (POP) levels in serum collected from children (11-15 years old) working and sometimes also living at the municipal waste-disposal site in Managua, located at the shore of Lake Managua, and in nonworking children living both nearby and also far away from the waste-disposal site. The influence of fish consumption was further evaluated by assessing POPs levels in serum from young women (15-24 years old) with markedly different patterns of fish consumption from Lake Managua. 2,2-bis(4-chlorophenyl)-1,1,1-trichloro-ethane (4,4'-DDT) and 2,2-bis(4-chlorophenyl)-1,1-dichloro-ethene (4,4'-DDE), gamma-hexachlorocyclohexane (gamma-HCH), polychlorinated biphenyls, pentachlorophenol, and polychlorobiphenylols were quantified in all samples. In general, the levels observed were higher than those reported in children from developed countries, such as Germany and United States. Toxaphene, aldrin, dieldrin, and beta-HCH could not be identified in any sample. The children working at the waste-disposal site had higher levels of POPs compared with the nonworking reference groups. In children not working, there were also gradients for several POPs, according to vicinity to the waste-disposal site. Moreover, in children, as well as in young women, there were gradients according to fish consumption. The most abundant component was 4,4'-DDE, but at levels still lower than those reported in children from malarious areas with a history of recent or current application of 4,4'-DDT for vector control.