间作牧草对茶园螨类群落多样性的影响

Effects of cover crops on mite communities in tea plantations

螨类是茶园生态系统中重要且复杂的类群之一。为了了解不同植物间作后对茶园螨类群落的组成结构和多样性的影响,2006年3月至2008年4月,在武夷山市星村镇大坪洲茶园通过间作百喜草(Paspalum notatum)或圆叶决明(Cassia rotundifolia)、留养杂草和除杂草4种不同处理,对茶园茶冠层(采用盆拍法及剪枝条法)和凋落层(采用捡取凋落物法)的螨类进行系统采样、标本鉴定和统计分析。结果表明:与留养杂草对照相比,间作百喜草或圆叶决明均显著增加了茶冠层和凋落层捕食螨的物种丰富度(S)、有效多样性指数(eH′)、个体数(N)和绝对丰度(n)。与留养杂草和除杂草这两种对照相比,间作百喜草或圆叶决明均显著增加了茶冠层和凋落层优势种圆果大赤螨(Anystis baccarum)的个体数(N)。茶冠层植食螨和腐食螨及凋落层腐食螨的所有群落指标在不同处理茶园间均无显著差异。茶冠层和凋落层螨类群落物种丰富度(S)和个体数(N)季节性变化明显,物种组成相似性高。间作茶园和留养杂草茶园茶冠层的螨类总个体数与其对应的凋落层螨类总个体数呈显著正相关。多样化茶园有利于保护和利用捕食螨,从而对茶园有害生物进行生态控制,促进有机茶叶可持续生产。

Mites form one of the most important and complex communities of arthropods in tea plantations.We examined the responses of mite communities in terms of species composition,structure and diversity in tea plantations subjected to two types of intercropping.Samples were collected between March 2006 and April 2008 from tea canopies using both knock-down and pruning methods,and from ground litter in four different treatments in tea plantations in the Wuyi Mountains.Results from both canopy and litter samples showed that tea plantations intercropped with Paspalum notatum or Cassia rotundifolia had significantly higher species richness （S）,effective diversity index （e H＇）,number of individuals （N）,and absolute abundance （n） of predatory mites than in control tea plantations with natural vegetation.Plantations intercropped with P.notatum or C.rotundifolia displayed a significantly higher number of individuals （N） of Anystis baccarum,a common predatory species,for both canopy and litter samples versus the tea plantation with natural ground cover and on bare ground.Species richness,number of individuals,and diversity indices of both phyto-phagous and saprophagous mite communities collected from tea canopies and of saprophagous mite commu-nities in litter were not different among the various intercropping treatments.Seasonal dynamics in mite spe-cies richness （S） and number of individuals （N） were apparent for all treatments.Czekanowski similarity in-dices suggested that these communities were highly similar to each other.For the tea plantation intercropped with P.notatum or C.rotundifolia,or with natural ground cover,the total number of mites in tea canopies was positively associated with the total number of mites in the litter.We suggest that diversifying tea agroecosystems by using intercrops can bolster predatory mite densities,thus providing a viable strategy for pest management and promoting the environmentally benign production of tea products.