85.4.10广州绿化树木风害的分析

水文对发生在1985年4月10日的一场风暴袭击下广州绿化树木风害进行了分析。这是一场时间短而破坏性大的风暴,致使许多绿化树木遭受倒、折、扭和裂等损害。在对绿化树木风过害的调查研究和分析的基础上,水文阐明了绿化树木风害的大小除与主要的因素风力有密切关系外,其严重程度还决定于树木的健康、生长状况、生态环境和管理水平等因素,并同时讨论了防卸树风害的有效措施。木     

SOCIETY FOR EXPERIMENTAL BIOLOGY CONFERENCE,UNIVERSITY OF ST. ANDREWS,APRIL 1995

We describe the interactive nature of vocalizations emitted by African elephant (Loxodonta africana) family groups while visiting waterholes. Despite being in close visual contact with each other, individuals called interactively within a series of overlapping or antiphonal vocal bouts that increased significantly while departing from the waterhole. After initiating departure from the waterhole, elephants in this study increased their calling rate and their production of overlapping vocal bouts. The majority of calls either overlapped or occurred within 1.5 seconds of another call as part of an antiphonal bout, rather than as isolated calls. The departure of larger herds was accompanied by a greater number of calling bouts. The increase in interactive antiphonal bouts during departure might serve to facilitate group coordination and cohesion, as well as possibly reinforce social bonds. The longer repeated bouts could also facilitate eavesdropping by distant elephants by boosting signal detection since the repetition of these longer calls may yield an increase in the signal-to-noise ratio (SNR) that reduces the noise floor for better longer distance communication.