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431.
Social and mating system of cooperatively breeding laughing kookaburras (Dacelo novaeguineae) 总被引:4,自引:0,他引:4
DNA fingerprinting was combined with field observations over four breeding seasons to investigate the social structure and
mating system of the laughing kookaburra (Dacelo novaeguineae). Groups comprised a socially dominant pair and up to six helpers of either sex. Helpers were always recruited from young
hatched in the group. Territorial inheritance, which is a feature of other cooperative breeders and an oft-cited benefit of
philopatry, did not occur. Helpers only attained dominant status in an established group by dispersing into a vacant dominant
position in that group. However, helpers could also form new groups by excising a new territory, often through a ”budding”
process. The mating system was overwhelmingly monogamous. There were no cases of extra-group parentage in a sample of 140
nestlings; within groups of three or more birds, dominance predicted parentage almost perfectly (99.2% of 129 nestlings),
irrespective of whether helpers in the group were related to one or both dominant birds. This is contrary to predictions from
models of reproductive skew, possibly because they currently fail to incorporate the willingness of females to share reproduction
among males.
Received: 15 May 1999 / Received in revised form: 2 November 1999 / Accepted: 6 November 1999 相似文献
432.
T. Lubjuhn Wolfgang Winkel Jörg Thomas Epplen Jörg Brün 《Behavioral ecology and sociobiology》2000,48(1):12-17
One of the most interesting aspects of the mating system of pied flycatchers is the regular occurrence of polygyny. Here we
present data on the reproductive success of polygynously paired pied flycatcher males compared to monogamous males based on
paternity analyses through DNA fingerprinting. Males paired with two females suffered a higher loss in reproductive output
per female compared to monogamous males due to (1) a greater proportion of unhatched eggs in their broods, (2) greater nestling
mortality and (3) a greater probability of being cuckolded. Nevertheless, the number of fledglings was significantly greater
for polygynous males. Based on the number of nestlings that returned for subsequent breeding seasons, however, the reproductive
success of monogamous and polygynous males did not differ significantly. These data raise the question as to why males attempt
polygyny.
Received: 16 August 1999 / Received in revised form: 15 March 2000 / Accepted: 18 March 2000 相似文献
433.
战略环境评价系统及工作程序 总被引:26,自引:0,他引:26
介绍了战略环境评价系统组成的五个要素 ,即评价者、评价对象、评价目的、评价标准和评价方法 ,分析了其相互关系及各要素与战略环境评价系统的关系 ,并提出了战略环境评价工作程序。 相似文献
434.
松嫩盆地资源环境信息系统空间数据库的设计与开发 总被引:6,自引:0,他引:6
杨建强 《城市环境与城市生态》2000,13(4):17-19
文章介绍了松嫩盆地资源环境信息系统空间数据库的设计思路,总体目标、构成及功能以及系统建立的关键技术。该系统的建立,使得对松嫩盆地资源开发管理和相关信息的查询、检索更方便,同时对松嫩盆地资源合理开发利用和管理决策提供了科学依据。 相似文献
435.
采用充纯氧及固定化细胞技术在275.5m市政下水管网系统中进行了日处理1500m^3污水的中试。对单纯充氧、充氧加固定化细胞二种工艺及不同 氧量刊物了比较研究。结果表明,在加固定化细胞条件下,充纯氧(V(O2):V(H2O)=0.078:1)可使流过此段管道的污水的污染物去除65%以上,基本达到国家污水综合排放二级标准。 相似文献
436.
Uncertainty plays a major role in Integrated Coastal Zone Management (ICZM). A large part of this uncertainty is connected
to our lack of knowledge of the integrated functioning of the coastal system and to the increasing need to act in a pro-active
way. Increasingly, coastal managers are forced to take decisions based on information which is surrounded by uncertainties.
Different types of uncertainty can be identified and the role of uncertainty in decision making, scientific uncertainty and
model uncertainty in ICZM is discussed. The issue of spatial variability, which is believed to be extremely important in ICZM
and represents a primary source of complexity and uncertainty, is also briefly introduced. Some principles for complex model
building are described as an approach to handle, in a balanced way, the available data, information, knowledge and experience.
The practical method of sensitivity analysis is then introduced as a method for a posterior evaluation of uncertainty in simulation
models. We conclude by emphasising the need for the definition of an analysis plan in order to handle model uncertainty in
a balanced way during the decision making process. 相似文献
437.
438.
439.
地表水环境遥感监测关键技术与系统 总被引:1,自引:0,他引:1
介绍了地表水环境遥感监测的关键技术与系统及其典型应用,其代表性机理模型和应用示范成果主要来自于中国科学院遥感与数字地球研究所的高光谱遥感团队在最近几年中取得的一些研究进展,主要包括建立了基于改进双峰法的水体分布自动化遥感提取方法,实现了简单、高效和高精度的水体提取;提出了大型湖泊长时序水量估算方法,并以青藏高原湖区为例,重建了典型湖泊面积、水位和水量序列;发展了基于“软分类”的典型内陆水体叶绿素a浓度反演方法,构建了基于生物光学模型的高度浑浊水体悬浮物浓度遥感反演半解析方法,提高了反演方法的区域和季节适用性;构建了基于水色指数的大范围湖库营养状态和透明度遥感监测方法,实现了全球大型湖库营养状态遥感监测,以及全国大型湖库透明度遥感监测;在此基础上,开发了地表水环境遥感监测系统,提高了水环境遥感监测效率,促进了卫星遥感在水环境监测中的高精度业务化应用。 相似文献
440.
基于环境空气VOCs自动监测系统中动态稀释校准仪在相同稀释比和不同稀释流量条件下,对仪器测试结果误差的影响进行研究,指出了当前环境空气VOCs自动监测普遍使用的校准仪的不足之处。选取臭氧前体物(PAMS) 57种有机化合物,以不同稀释总流量,分别测试0. 5和1. 0 nmol/mol的平均检出限以及平均回测偏差,结果显示,在输出流量1 000 m L/min时,平均检出限分别在0. 02~0. 17和0. 01~0. 10 nmol/mol;平均回测偏差在-12%~26%和-28%~10%。当总输出流量 1 000 m L/min时,多点曲线各浓度点重复性5%。 相似文献