薛世玉 李小飞 徐大平 崔之益 张鹏 杨曾奖

摘  要：檀香（Santalum album Linn.）+降香黃檀（Dalbergia odorifera T.Chen.）混交林是当前我国南方地区珍贵树种种植的典型模式。为揭示不同抚育措施下其林下植被多样性的变化规律，探索林地环境对这一特殊寄生特性林分的影响。本研究选取8年生檀香+降香黄檀混交林，连续开展了3年铲草（W）、施肥（F）、铲草+施肥（W+F）抚育对其林下植被多样性影响的研究。结果表明，檀香+降香黄檀混交林下出现的植物种类为20科31属32种，其中木本植物6科7属8种，草本植物14科23属24种，抚育管理初期各处理间差异显著（P<0.05），铲草、铲草+施肥处理后相较于对照物种丰富度指数（R）、Simpson多样性指数（D）、Shannon-Wiener多样性指数（H）、Pielou均匀度指数（Jsw）显著下降（P<0.05），施肥处理变化较小。连续抚育管理后，R值对照、施肥处理平稳变化，铲草、铲草+施肥处理呈逐年上升趋势，并最终超越对照;D值、H值、Jsw值对照呈逐年降低趋势，施肥处理逐年上升，铲草、铲草+施肥先增加后减小，最终D值、H值、Jsw值均表现为施肥最高，铲草最低。施肥增加了林下物种多样性并表现出对林下物种多样性降低的一种拮抗作用，铲草则加剧了林下物种多样性降低。因此，从长远来看，施肥可增加檀香+降香黄檀混交林林下物种多样性，有利于其生态稳定性的提高。

关键词：混交林;铲草;施肥;林下植被;物种多样性

Abstract： The mixed forest of Santalum album + Dalbergia odorifera is a typical pattern of planting precious trees in southern China in recent years. In order to reveal the variation law of the understory species diversity under different management patterns， the influence of forest environment on this special parasitic characteristic stand was explored. In this study， 8-year-old Santalum album + Dalbergia odorifera mixed forest was selected， and the effects of weeding， fertilization， weeding + fertilization on the undergrowth species diversity were studied for 3 consecutive years. The results showed that there were 32 species， 31 genera and 20 families in the mixed forest including 8 species， 7 genera and 6 families of woody plants and 24 species， 23 genera and 14 families of herbaceous plants. There were significant differences among the treatments in the early management （P<0.05）， compared with the control species richness index （R）， Simpson diversity index （D）， Shannon-Wiener diversity index （H） and Pielou evenness index （Jsw） after weeding and weeding + fertilization， there was a significant decrease （P<0.05）， there was little change in fertilization treatment. After continuous management， R value control and fertilization treatment changed steadily， and weeding， weeding + fertilization treatment showed an increasing trend year by year and finally surpassed the control. The control treatment D value， H value and Jsw value decreased year by year， fertilization treatment increased year by year， weeding， weeding + fertilization increased first and then decreased， and finally D value， H value and Jsw value showed the highest fertilization and the lowest weeding. Fertilization increased the diversity of understory species and showed an antagonistic effect on the decrease of understory species diversity while weeding aggravated the decrease of understory species diversity. Therefore， in the long run， fertilization can increase the species diversity of Santalum album + Dalbergia odorifera mixed forest， which is also conducive to the improvement of its ecological stability.

Keywords： mixed forest; weeding; fertilization; understory species; species diversity

物种多样性反映出森林群落中各物种对资源环境的竞争及协调利用并最终共存的结果，是群落功能复杂性和稳定性的重要度量指标[1-2]。林下植被是生态系统的重要组成部分，在维护整个系统的生态功能稳定性、物种多样性、持续生产力和立地指示方面有着特有的功能和作用[3-4]。人工林生物多样性是影响人工林生态系统稳定性的重要因素，在一定程度上可以反映人工林可持续经营的水平，因此，倍受国内外学者关注[5-7]。以往对于人工林林下植被多样性的研究多集中在桉树[8-9]、杉木[10-11]、马尾松[12-13]等速生短周期树种，对于目前大力发展的长周期珍贵树种林下物种多样性的研究鲜见报道。

檀香+降香黄檀混交林是当前南方地区广泛种植的珍贵树种人工林，近年来随着推广种植面积不断扩大，其生态效益也愈加突出。……