Sleeping sites of Rhinopithecus bieti at Mt. Fuhe, Yunnan

Data on sleeping site selection were collected for a group of black-and-white snub-nosed monkeys (Rhinopithecus bieti; around 80) at Mt. Fuhe, Yunnan, China (99degrees20'E, 26degrees25'N, about 3,000 m asl) from November 2000 to January 2002. At the site mainly three vegetation types were present in an elevation-ascending order: deciduous broad leaf forest, mixed coniferous and broad leaf forest, and dark coniferous forest. In addition, bamboo forest presented in areas burned in 1958. Sleeping sites (n = 10) were located in the coniferous forest, where trees were the tallest, bottommost branches were the highest, the diameter of crowns was the second largest, and the gradient of the ground was the steepest. Monkeys usually kept quiet during entering and staying at a sleeping site. The site choice and the quietness may be tactics to avoid potential predators. In the coniferous forest, however, monkeys did not sleep in the valley bottom where trees were the largest, but frequently slept in the middle of the slope towards the east/southeast, in the shadow of ridges in three other directions, to avoid strong wind and to access sunshine; in winter-spring, they ranged in a more southern and lower area than in summer-autumn. These may be behavioral strategies to minimize energy stress in the cold habitat. Monkeys often slept in the same sleeping site on consecutive nights, which reflected a reduced pressure of predation probably due to either the effectiveness of anti-predation through sleeping site selection, or the population decline of predators with increasing human activities in the habitat. The group's behavioral responses to interactive and sometimes conflicting traits of the habitat are site-specific and conform to expectations for a temperate zone primate.

Deceptive female oviposition behaviour elicits male ejaculation in the European bitterling

In European bitterling Rhodeus amarus, fish that lay their eggs in the gill chambers of living freshwater mussels, females perform conspicuous behaviours associated with spawning that increases the probability of males performing ejaculatory behaviour and participating in a spawning. A significant positive association was detected between behaviour in which a female performs a spawning action but without releasing eggs, here termed 'deceptive female oviposition', and ejaculatory behaviour by courting males.

黄土高原植被恢复与建设策略

以中国水土流失与生态安全综合科学考察——西北黄土区考察组获得的资料为依据,对黄土高原地区植被恢复的基础和潜力进行了系统分析,提出了植被恢复的目标和策略。黄土高原天然群落恢复的基本措施是封育,有条件的区域应实施人工促进,使植被自然恢复力与人为促进力相结合;人工植被建设应充分利用乡土树草种,合理利用外来种,采用防护性整地和管理措施,造林种草后引导乡土物种进入群落,进行天然化培育;以流域为治理单元,优化景观斑块空间布局和面积构成,逐步改造具有退化特征的人工群落,使建群种能够自我更新,群落可永续利用;政府部门在政策上要保护现有成果,扩大自然修复比例;保护大户承包治理的积极性,鼓励多元化投资,进行植被建设;扩大黄土区植被建设和科研投资力度,培育黄土区植被恢复方面的科技创新能力。

中国西部退耕还林基本策略研究

21世纪,生态危机成为人类面临的最大威胁,森林作为陆地生态系统的主体,自然成为世人瞩目的集点.由于中国西部水土流失、土地沙化、水资源紧张、生物多样性锐减等问题越来越突出,给人民的生活与国民经济发展造成巨大损失.退耕还林成为中华民族生存与发展的根本大计,这不仅关系到当代人的生存与发展,而且关系到子孙后代的生存与发展.文章在上述背景下,提出了符合中国实际的对策,供决策部门参考.

纸房沟流域生态经济系统演变分析

通过对纸房沟流域土地利用结构和收入结构的简要分析 ,提出了生态系统与经济系统演变的一般规律 ,受生态系统与经济系统演变规律的启示 ,提出了纸房沟流域生态经济系统进一步建设的策略。

基于网络环境的地理信息系统-WebGIS

Web GIS作为一门新兴的技术学科 ,依托互联网的环境和 Internet实用技术 ,成为地理信息系统理论研究和技术创新的增长点。随着网络技术和应用市场的不断发展和扩大 ,将促进 GIS新兴信息产业的形成。本文结合工作实践 ,论述了 Web GIS的技术背景与发展 ,以及系统功能等基础理论 ,重点讨论了 Web GIS的体系结构、实现策略和技术方法

一个用于自治智能移动式机器人导航和监控的实验系统

文中重点讨论了系统实现过程中,任务分解与行走命令下达,时序分配与同步,路标定位与行走误差修正.动态障碍感知,测定与响应和特别情况紧急处理等难题的解决策略及遇到的问题.