食螨瓢虫自然种群基地建立的研究

腹管食螨瓢虫Stethorus siphonulus Kapur是福建省柑桔全爪蠕(红蜘蛛)Panonychus eitri MeGregor的优势种天敌,控制作用显．已在我省柑桔产区大面积应用成功。为了使柑桔全爪蠕生物防治持续发展,古螨瓢虫自然种群基地的建立至关重要．本将多年来在闽清白中柑桔场、福建农业大学金山柑桔园、福州北郊峙头柑桔场、长泰柑桔园等地进行食螨瓢虫自然种群基地建立的研究,进行总结报道。     

Seedling Establishment of a Canopy Tree Species in Malaysian Tropical Rain Forests

Abstract Unlike many other canopy tree species in tropical rain forests, Dryobalanops aromatica (Dipterocar-paceae, local name: Kapur) establishes monospecific dominant (monodominant) forests in Peninsular Malaysia. In natural conditions, monodominance of Kapur does not necessarily mean low species diversity of the Kapur forests. While the emergent canopy layer is occupied by Kapur, many other plant species, which are common to lowland dipterocarp primary forests in the same region, are found in lower canopy layer and understory.
To understand the ecological implications of the monodominance of Kapur, we monitored post dispersal survival and seedling establishment in a pure stand of Kapur in a plantation in Kepong, near Kuala Lumpur. Immediately after seed fall, seeds and cotyledon-stage seedlings suffered high predation by vertebrates such as rodents. The predation pressure was higher in a more general fruiting year (1991) than in a sporadic fruiting year (1992). In contrast to the high mortality of seeds and newly emerged seedlings, seedlings surviving to the six-leaf stage showed low mortality, which allowed the establishment of a sapling bank.
The occurrence of saplings of Kapur with a wide range of size classes in natural forests indicates that this species is more shade tolerant than other dipterocarp species such as the Shorea group and that it could well respond to enhanced light conditions caused by canopy opening. These characteristics may partly contribute to maintaining monodominance of Kapur.