摘要:提升农田生物多样性是当前生态农业研究的热点问题。为探讨农田防护林的生物多样性保护功能，本研究在辽宁省昌图县金家镇选取8个农田-防护林单元(每个单元即为1个田块)，使用陷阱法调查了不同类型林带(完整型、残缺型、消亡型)相邻的农田中，距林带不同距离处(0 m、50 m、100 m、150 m、200 m)地表节肢动物的分布情况，同时记录林带内的植被群落特征。采用方差分析以及群落排序的方法，分析了林带类型、距离梯度以及林带植被结构对农田地表节肢动物分布的影响。研究结果表明：1)与消亡型相比，完整型和残缺型林带相邻的农田物种多度显著较高，物种多样性在各类型林带农田间无显著差异，与完整型及残缺型林带相邻的农田维持着区别于消亡型林带的地表节肢动物群落结构。2)完整型和残缺型林带相邻的农田物种多度梯度变化显著，随距林带距离的增加均呈由低到高的变化趋势；不同类型林带农田中，物种多样性随距林带距离的增加逐渐递减，边缘效应显著。3)林带中草本层物种多度和乔木层盖度是影响农田地表节肢动物群落分布的主要因子，共解释了35.4%的节肢动物数量变异；不同节肢动物物种对林带植被结构的响应存在差异，步甲和蜘蛛作为当地农业景观中主要的天敌类群，与上述林带植被结构因子关系密切：林带内较高的草本层物种多度有利于增加农田中某些步甲常见种的多样性，而较高的乔木层盖度有利于增加蜘蛛目常见科的多样性。研究结果表明，农田防护林作为研究区主要的非耕作生境类型，能够显著提升相邻农田中地表节肢动物的多度，对于物种多样性的提升作用则不明显；林带内草本层物种多度以及乔木层盖度对蜘蛛、步甲等多类天敌多样性保护具有积极作用。因此，加强农业景观中现有林地的改造和提升，如营造适宜盖度的上层林木以及丰富的林下植被，能够提升现有林地的生境质量，进一步发挥其对农田生物多样性的保育功能。
关键词:农田防护林/
昌图县/
地表节肢动物/
分布/
群落结构
Abstract:Improving farmland biodiversity is important for ecological agriculture. To explore how well farmland shelterbelts protect biodiversity, eight farmland shelterbelt units (unit=one field parcel; shelterbelt types:complete, incomplete, or extinct) in Jinjia Town, Changtu County, Liaoning Province, China were selected, and the surface arthropod distribution in adjacent farmlands was investigated using pitfall traps. Surface arthropods were sampled at 0, 50, 100, 150, and 200 m from the shelterbelt, and the shelterbelt vegetation characteristics were recorded. Analysis of variance and community ordination were used to analyze how the shelterbelt type, distance gradients, and shelterbelt vegetation structure affected the surface arthropod distribution. The results showed that the surface arthropod abundance was significantly higher in fields adjacent to complete and incomplete shelterbelts. The shelterbelt type had no significant effect on diversity; however, the surface arthropod community composition on the farmland adjacent to complete and incomplete shelterbelts differed from the extinct shelterbelts. The abundance gradient variation was significant in fields adjacent to complete and incomplete shelterbelts, demonstrating a low to high variation trend with away from shelterbelts. In all units, the diversity decreased as the distance toward the edge increased, and a significant edge effect was observed. Redundancy analysis (RDA) and Monte Carlo tests showed that the herb layer species abundance and the shelterbelt tree coverage were the primary factors affecting arthropod community distributions, accounting for 35.4% of the total surface arthropod population variation. Arthropod responses to the shelterbelt vegetation community significantly differed based on the species, carabids, and spiders present. The primary natural enemy of the local agricultural landscape was closely related to the shelterbelt vegetation structure; the carabid species diversity was positively associated with herb layer abundance, and the spider family diversity was positively associated with tree coverage. Farmland shelterbelts (a non-cropped habitat) significantly increased the number of surface arthropods in adjacent fields but did not affect species diversity. The herb layer abundance and shelterbelt tree coverage had a positive effect on natural enemy diversity (e.g., carabids and spiders). Strengthening agricultural landscape woodlands, such as increasing upper tree coverage and understory vegetation, improves the habitat quality and conserves farmland biodiversity, thereby promoting sustainable agriculture.
Key words:Farmland shelterbelts/
Changtu County/
Surface arthropods/
Distribution/
Community structure
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