浙江省生态公益林植被恢复过程中物种组成及多样性的变化

在浙江省生态公益林区域的现状植被中分析了6种主要群落类型的物种组成和多样性的变化格局,包括演替系列中的2种灌丛、松优势林、2种混交林和常绿阔叶林。结果表明含松较多的灌丛和松优势林常分布在环境退化较严重(土层瘠薄)的生境中,其中灌木层主要由阳性的映山红、木、白栎等组成,常绿阔叶林优势种木荷、青冈、苦槠、甜槠等在其中偶见,因此推断其自然恢复为常绿林的速度慢;含常绿阔叶树较多的灌丛及含松较少的混交林分布在土层较厚处,木荷、青冈、苦槠、甜槠等的频度和重要值都较大,较容易自然恢复为常绿阔叶林。各种群落中物种多样性指数——Gleason、Shannon-Wiener、Simpson指数基本上以常绿阔叶林为最高,其次是含松较少的混交林,含松较多的灌丛和松优势林各种多样性指数最低。本研究显示我国中亚热带东部森林植被恢复途径有3条:(1)灌草丛→针叶林(松)→针(松)阔混交林→常绿阔叶林;(2)灌草丛→针(松)阔混交林→常绿阔叶林;(3)灌草丛→常绿阔叶林。这意味着本区域的常绿阔叶林恢复可以不必经历松林阶段,在生境条件较好的地方通过人工干预、补种常绿阔叶树可以加速常绿阔叶林恢复。     

The role of land-use history in driving successional pathways and its implications for the restoration of tropical forests

Secondary forests are increasingly important components of human-modified landscapes in the tropics. Successional pathways, however, can vary enormously across and within landscapes, with divergent regrowth rates, vegetation structure and species composition. While climatic and edaphic conditions drive variations across regions, land-use history plays a central role in driving alternative successional pathways within human-modified landscapes. How land use affects succession depends on its intensity, spatial extent, frequency, duration and management practices, and is mediated by a complex combination of mechanisms acting on different ecosystem components and at different spatial and temporal scales. We review the literature aiming to provide a comprehensive understanding of the mechanisms underlying the long-lasting effects of land use on tropical forest succession and to discuss its implications for forest restoration. We organize it following a framework based on the hierarchical model of succession and ecological filtering theory. This review shows that our knowledge is mostly derived from studies in Neotropical forests regenerating after abandonment of shifting cultivation or pasture systems. Vegetation is the ecological component assessed most often. Little is known regarding how the recovery of belowground processes and microbiota communities is affected by previous land-use history. In published studies, land-use history has been mostly characterized by type, without discrimination of intensity, extent, duration or frequency. We compile and discuss the metrics used to describe land-use history, aiming to facilitate future studies. The literature shows that (i) species availability to succession is affected by transformations in the landscape that affect dispersal, and by management practices and seed predation, which affect the composition and diversity of propagules on site. Once a species successfully reaches an abandoned field, its establishment and performance are dependent on resistance to management practices, tolerance to (modified) soil conditions, herbivory, competition with weeds and invasive species, and facilitation by remnant trees. (ii) Structural and compositional divergences at early stages of succession remain for decades, suggesting that early communities play an important role in governing further ecosystem functioning and processes during succession. Management interventions at early stages could help enhance recovery rates and manipulate successional pathways. (iii) The combination of local and landscape conditions defines the limitations to succession and therefore the potential for natural regeneration to restore ecosystem properties effectively. The knowledge summarized here could enable the identification of conditions in which natural regeneration could efficiently promote forest restoration, and where specific management practices are required to foster succession. Finally, characterization of the landscape context and previous land-use history is essential to understand the limitations to succession and therefore to define cost-effective restoration strategies. Advancing knowledge on these two aspects is key for finding generalizable relations that will increase the predictability of succession and the efficiency of forest restoration under different landscape contexts.     

间伐对日本落叶松人工林林下更新木本植物组成和生长影响的时间效应

明确间伐对针叶人工林林下更新阔叶木本植物组成和生长影响的时间效应,可为促进人工纯林向针阔混交林转化、进而解决纯林生产与生态功能无法兼顾的问题提供参考。本研究以我国北方重要针叶人工林——日本落叶松人工林为例,比较间伐后短期(1～3年)、中期(4～9年)和长期(>9年)人工林林下更新木本植物组成的差异;并选择具有较高重要值且与落叶松互惠共生的3种更新树种蒙古栎、色木槭、糠椴,分析不同间伐时期人工林内光照(郁闭度)与更新木本植物生长的关系。结果表明: 在间伐样地内更新的阔叶木本植物达46种,不同间伐时期样地内共有且占据优势的乔木树种为色木槭,灌木树种为忍冬和卫矛。随间伐后时间的推移,更新物种数逐渐减少,但乔灌比呈增大的趋势;中性树种占据优势地位。间伐对更新树种生长影响的时间效应受树种耐荫性的影响,糠椴的基径和树高均高于蒙古栎和色木槭。随间伐后时间的延长,糠椴的基径、色木槭的树高对光照响应较敏感,分别倾向于采用“耐荫策略”和“避荫策略”以适应间伐后变化的环境。间伐对日本落叶松人工林林下更新阔叶木本植物组成和生长的影响具有明显的时间效应;在制定以促进人工林林下树种更新为目标的间伐措施时,应该考虑适当延长间伐间隔,从而保证糠椴和色木槭等阔叶树幼苗的生长,使其进入林冠层,促进形成针阔混交林,实现人工林的可持续发展。     

The influence of resprouting forest canopy species on richness in Southern Cape forests, South Africa

We investigated the relationship between species richness and numbers and types of individuals and species present in forests with different physiognomies in the southern Cape Province, South Africa. Data were collected from three different ‘plot’ types: 400 m², canopy‐scaled (plot length is directly proportional to canopy height) and per 100 individuals closest to a point. Plots were designed to control for the effect of scale on local richness. Canopy species richness was inversely proportional to the abundance of resprouting species. The strength of the relationship between the abundance of resprouters and canopy species richness increased progressively from the 400 m² plots to the canopy‐scaled plots and finally to the plots of 100 individuals. Resprouter abundance decreased, while canopy species richness increased, with increasing canopy height. Resprouters are able to retain their in situ position in the forests for longer periods of time than do reseeders. This reduces individual and species turnover, thus reducing species richness in resprouter‐dominated forests.     

Elevated CO2 influences the responses of two birch species to soil moisture: implications for forest community structure

Increased levels of atmospheric CO₂ may alter the structure and composition of plant communities by affecting how species respond to their physical and biological environment. We investigated how elevated CO₂ influenced the response of paper birch ( Betula papyrifera Marsh.) and yellow birch (Betula alleghaniensis Britt.) seedlings to variation in soil moisture. Seedlings were grown for four months on a soil moisture gradient, individually and in mixed species stands, in controlled environment facilities at ambient (375 μL L^–1) and elevated (700 μL L^–1) atmospheric CO₂. For both individually and competitively grown paper birch seedlings, there was a greater CO₂ growth enhancement for seedlings watered less frequently than for well-watered seedlings. This differential change in CO₂ responsiveness across the moisture gradient reduced the difference in seedling growth between high and low water levels and effectively broadened the regeneration niche of paper birch. In contrast, for yellow birch seedlings, elevated CO₂ only produced a significant growth enhancement at the wet end of the soil moisture gradient, and increased the size difference between seedlings at the two ends of the gradient. Gas exchange measurements showed that paper birch seedlings were more sensitive than yellow birch seedlings to declines in soil moisture, and that elevated CO₂ reduced this sensitivity. Additionally, elevated CO₂ improved survival of yellow birch seedlings growing in competition with paper birch in dry stands. Thus, elevated CO₂ may influence regeneration patterns of paper birch and yellow birch on sites of differing soil moisture. In the future, as atmospheric CO₂ levels rise, growth of paper birch seedlings and survival of yellow birch seedlings may be enhanced on xeric sites, while yellow birch may show improved growth on mesic sites.     

鄂西南木林子常绿落叶阔叶混交林恢复过程中优势树种生态位动态

运用Shannow-wiener生态位宽度指数和Pianka生态位重叠指数,分析了鄂西南木林子常绿落叶阔叶混交林恢复过程中优势树种生态位动态。结果表明:大穗鹅耳枥(Carpinus fargesii)、四照花(Cornus kousa var.Chinensis)、青冈(Cycloblanopsis glauca)生态位总宽度较大,且在5个不同恢复时期均有分布。恢复期14a、35a、60a、85a和110a生态位宽度最大的树种分别为白马桑(Weigela japonica var.sinica)、大穗鹅耳枥、四照花、光皮桦(Betula luminifera)和尾叶冬青(Ilex wilsonii)。随着群落的恢复,优势落叶树种生态位宽度表现出下降趋势,优势常绿树种则呈上升趋势。当恢复到顶极群落阶段,乔木层常绿和落叶树种生态位接近,灌木层常绿灌木占据较大生态位。随着群落的恢复,优势落叶树种与其它树种的生态位重叠值呈波动性下降趋势,优势常绿树种表现为波动性上升趋势,群落全部树种间生态位重叠程度呈小幅度波动性下降趋势。相同或相似生活型的演替早期种间的高生态位重叠,意味着种间对资源利用的相似性和竞争关系,演替后期种与其它树种间的生态位重叠的增加,意味着不同生活型树种在水平空间重叠而在垂直空间分化,这是不同树种对有限环境资源充分利用的一种机制。     

Structural characteristics and canopy dynamics of Tsuga canadensis in forests of the southern Appalachian Mountains, USA

Tsuga canadensis (L.) Carr. forests of the southern Appalachian Mountains are currently facing imminent decline induced by a nonnative insect pest, the hemlock woolly adelgid (Adelges tsugae Annand). To effectively manage these forest systems now and in the future, land managers need baseline data on forest structure and dynamics prior to large-scale Tsuga canadensis mortality. Most of our knowledge concerning the dynamics of Tsuga canadensis forests comes from more northern locations such as the Great Lakes region and New England and, therefore, may not pertain to the ecological systems found within the southern Appalachian Mountains. We examined the structure and canopy dynamics of four Tsuga canadensis forest stands within the Cataloochee watershed, in the far eastern part of Great Smoky Mountains National Park (GSMNP). We characterized the environmental settings and vertical forest layers, as well as the diameter and age-structures of each Tsuga canadensis forest stand. These environmental and structural data showed that there were indeed differences between forest stands with and without successful Tsuga canadensis regeneration. The two forest stands exhibiting successful Tsuga canadensis regeneration were located above 1,000 m in elevation on well-drained, moderately steep slopes and had the greatest canopy openness. Structural data from these two forest stands indicated a history of more continuous Tsuga canadensis regeneration. We also constructed disturbance chronologies detailing the history of canopy response to disturbance events and related these to Tsuga canadensis regeneration within each forest stand. Student t-tests adjusted for unequal variances indicated significant differences in the number of release events per tree between forest stands with and without successful Tsuga canadensis regeneration. While forest stands with successful Tsuga canadensis regeneration were more frequently disturbed by minor to major canopy disturbances, events of moderate intensity were found to be most significant in terms of regeneration. These data will be of value to land managers maintaining stands of Tsuga canadensis where treatment for hemlock woolly adelgid infestation has been successful. In areas where treatment is impractical or unsuccessful, land managers will be able to use these data to restore Tsuga canadensis forests after the wave of hemlock woolly adelgid induced mortality has passed. As of August 2008, Joshua A. Kincaid will be a member of the Environmental Studies program at Shenandoah University in Winchester, Virginia, USA     

人为干扰对风水林群落林下木本植物组成和多样性的影响

华南地区的风水林是乡村聚落的一种特色林分, 具有守护村庄的象征意义。在过去的数百年中, 风水林在乡村的社会文化习俗的影响下而受到保护, 对当地的生物多样性保育有着重要作用。为揭示人为干扰对风水林的影响, 我们选择广东省东莞市大岭山镇同一林分起源的3个具有相似地形的风水林, 研究了在不同干扰强度下其林下木本植物种类组成和物种多样性。多响应置换过程(multi-response permutation procedures, MRPP)分析表明, 人为干扰显著改变了风水林林下木本植物组成(P = 0.001, A = 0.3886), 沿着干扰由弱至强的梯度呈现出中生性植物减少、阳生性植物递增的趋势。多样性指数变化趋势为重度干扰＞中度干扰＞轻度干扰, 但没有表现出统计学意义上的差异(P＞0.05)。随着干扰强度的增大, 3个风水林群落相互间的林下物种相似性降低, 物种替代率呈增加趋势。双向聚类分析较好地反映出林下物种因受不同人为干扰强度影响而表现出在空间分布上的差异。指示种分析进一步确定了不同干扰强度下具有显著指示值(IV ≥60)的指示种。综合分析表明, 人为干扰有利于阳性物种在风水林内定居生长, 并明显地改变了林下木本植物组成, 但未能引起物种多样性的显著差异。此外, 找出对人为干扰产生关键生态响应的林下指示种, 对增进风水林的生物多样性保育以及生态系统管理有着重要的理论意义和实践价值。     

Colonization of woody seedlings in the understory of actively and passively restored tropical moist forests

The status of woody seedling colonization gives clues about the self‐sustainability of restored forests, a tenet of restoration success. Little is known about woody seedling colonization in restored afrotropical forests. We evaluated effects of restoration methods (active vs. passive), sampling year, restoration age, and distance from old‐growth forests on seedling colonization in restored afrotropical moist forests. Seedlings were measured in 2011 and 2014 in 71 clusters of 284 permanent sampling plots (12.6 m² each) in actively (initially 3–16 years old) and 21 clusters of 63 plots in passively restored forests (initially 16 years old) in Kibale National Park, western Uganda. Seedlings were also measured in nearby old‐growth forests in three clusters of five plots in 2014. We determined species diversity, richness, abundance per plot, and species composition as measures of seedling colonization in restored and old‐growth forests. We found that diversity, richness, and abundance of seedlings were significantly higher in passively than actively restored forests. Diversity and richness but not abundance significantly increased between sampling years and with restoration age. Distance from old‐growth forests did not significantly affect diversity, richness, and abundance. Species composition of actively and passively restored forests was different from that of old‐growth forests after 19 years since restoration started. Our results show that passive restoration should be the preferred method for recovering afrotropical forests, and highlight the effect of continued management on biodiversity of restored forests.     

Fragment shape and tree species composition in tropical forests: a landscape level investigation

Fragmentation of tropical forest alters community composition as a result of changes in forest shape. This paper uses 22 hypotheses to test the effect of fragment shape on tree species composition in Ghana, West Africa, within biological categories of regeneration guild, rarity, phenology and dispersal. For both regenerating and mature trees, relationships between species composition and the shape of forest fragments were complex; almost half were significant but many failed to support the established hypotheses. Irregular shaped fragments had high proportions of regenerating, light‐demanding pioneers and mature, animal‐dispersed species. Species common to Ghana formed the foundation of communities in fragments of all shapes. Investigation at the landscape level indicated broad patterns of species change. Rigorous hypothesis testing is needed, following extensive demographic work on the ground, before population dynamics within tropical forest fragments can be comprehended fully and applied to conservation management.     

湖南大围山杜鹃灌丛的群落组成及结构特征

灌丛是陆地生态系统中最重要的自然植被类型之一, 在植被演替、生物多样性保护和维持生态平衡等方面具有重要作用。本文基于2012年的样地资料, 对湖南大围山杜鹃(Rhododendron simsii)灌丛的物种组成和群落结构进行了分析。结果表明: 群落内共有维管束植物58种, 隶属于36科50属, 其中木本植物19种, 草本植物39种, 缺乏木质藤本; 区系以温带性质为主, 兼受热带亚热带区系的强烈影响; 群落外貌矮平, 灌木层个体集中在1-2 m高度级; 植被分类上, 该群落归属于山地中生落叶阔叶灌丛, 隶属于温性落叶阔叶灌丛群系组; 生活型以地面芽和高位芽植物为主, 反映了亚热带中山山顶温凉湿润的气候特点; 群落各层次优势种明显, 具有较高的稳定性和均匀性; 高度级和基径级分析表明群落内中等大小个体具有保守的生活史策略, 优势种杜鹃为远期衰退种群。综合分析结果表明, 该杜鹃灌丛尚处于群落演替的中期或前中期, 最终将演替为亚热带中山常绿落叶阔叶混交林或常绿阔叶林。     

Effects of flooding duration on species richness, floristic composition and forest structure in river margin habitat in Amazonian blackwater floodplain forests: implications for future design of protected areas

Rivers in central Amazonia experience annual water-level fluctuations of up to 14m, flooding vast areas of adjacent forest for periods ranging from a few to 270 days per year. At different sites, variation in the duration and type of flooding results in a mosaic of habitats that includes lakes, grasslands, forests, and streams. To study the effects of flood duration on plant species richness and floristic composition, two river margin sites were surveyed on the rivers Jaú and Tarumã-Mirim. Both areas are seasonally flooded by blackwaters, and plots were made at different topographic levels (lower, middle and upper slopes). All woody plants with DBH>5cm were inventoried in five 10 × 40m plots in each of the three topographic levels, which varied in length of flood duration and mean water level. Plant species richness did not vary significantly between topographic levels, but species composition varied substantially. At both study sites, the species composition exhibited distinctive distribution patterns with respect to the three topographic levels and river site. Differences in the distribution of dominant species in both sites probably relate to the ability of species to withstand seasonal flooding, although other edaphic factors associated with the topographic levels may also be important, especially for less-dominant, locally rare, and habitat generalist species. Species composition overlap among topographic levels at the two sites was highly variable ranging from 15% to 43%. Knowledge about the complex pattern of species composition and distributions between and among topographic levels and river sites is important for the preservation of the diverse flora of the blackwater forests and for the creation of future conservation management plans and design of protected areas in this ecosystem that will maintain the biodiversity.     

A comparison of species composition and stand structure between planted and natural mangrove forests in Shenzhen Bay,South China

Aims For assisting faster restoration of damaged or severely disturbed coastal ecosystems, selected mangrove species have been planted on previously mangrove-inhabited sites of the tropical and subtropical coasts of southern China. The objective of this study was to understand the stand dynamics of the planted mangroves and their functional traits in comparison with natural mangrove forests under similar site conditions.Methods Species composition, stand density, tree size distribution, and aboveground production were investigated along three transects in a 50-year-old planted mangrove stand and three transects in an adjacent natural mangrove stand in Shenzhen Bay, South China. Measurements were made on tree distribution by species, stand structure, and aboveground biomass (AGB) distribution. Analyses were performed on the spatial patterns of tree size distribution and species association.Important findings We found that the planted and natural mangrove stands did not differ in stand density, average diameter at breast height (DBH), species composition, and AGB. Spatial distribution of AGB and frequency at species level were also similar between the planted and natural stands. However, the traits in stand structure were more variable in the planted stand than in the natural stand, indicating higher spatiotemporal heterogeneity in the development and succession of planted mangroves. Geostatistical analyses show that both DBH and AGB were spatially auto-correlated within a specific range in the direction perpendicular to coastline. More than 60% of the variance in these attributes was due to spatial autocorrelation. The Ripley's K -function analysis shows that the two dominant species, Kandelia obovata and Avicennia marina, clumped in broader scales in the natural stand than in the planted stand and displayed significant interspecific competition across the whole transect. It is suggested that interspecific competition interacts with spatial autocorrelation as the underlying mechanism shaping the mangrove structure. This study demonstrates that at age 50, mangrove plantations can perform similarly in stand structure, spatial arrangement of selected stand characteristics and species associations to the natural mangrove forests.     

Pollination and breeding systems of woody plant species in tropical dry evergreen forests,southern India

Tropical dry evergreen forests (TDEF) are a unique forest type found along the east coast of India. They mostly occur as small, isolated fragments of varying sizes (0.5 to ≈10 ha) and are considered as endangered forests types in peninsular India. Although plant diversity is well documented in these forests, there is a paucity of ecological studies vital for conservation and for planning restoration activities. We studied reproductive biology of 13 woody species: four trees, six shrubs, and three lianas in fragments of TDEF in southern India. The phenology of reproduction, floral biology, anthesis and sexual system of each species were recorded. The pollination mode was assessed through observations of the visitation frequency of pollinators and from the floral characters. The breeding system was determined by hand-augmented self- and cross-pollination experiments. The plants flowered during the dry season from January to July. Plants of nine species had both flowers and fruits at the same time. Twelve species were hermaphrodites and one was polygamo-dioecious. Flowers of 11 species opened at dawn and two at dusk. Four species were self-incompatible and six were self-compatible. Natural fruit set ranged from 10% to 56%, self-incompatible species having low fruit set. Cross-pollen augmentation increased fruit set, suggesting presence of outcrossing in all species. The majority of plants species (85%) had a generalized pollination system, receiving visits from diverse insects, such as social bees, solitary bees, wasps, moths and flies. However, only few of them were functionally important for the species. Two species namely: Capparis brevispina and C. zeylanica had butterflies and birds, respectively, as their main pollinators. Our data reveal that there is a predominance of outcrossing in plant species and a generalized pollination system in these forests. We suggest that restoration of TDEFs is crucial as habitats, not only for wild plants but also for pollinating insects.     

天目山常绿落叶阔叶混交林优势种生物量变化及群落演替特征

利用天目山自然保护区内设立的典型亚热带常绿落叶阔叶混交林1 hm~2固定样地为基础,分别对1996年和2012年(时间跨度为16年)的实地调查监测数据进行综合处理分析,包括优势种的生态位宽度、生态位重叠、种间联结和生物量等方面对其群落演替特征进行深入探讨。结果表明:1996年到2012年中,优势种生态位宽度指数下降的有青钱柳(Cyclocarya paliurus)和缺萼枫香(Liquidambar acalycina),而上升较明显的有小叶青冈(Cyclobalanopsis myrsinifolia)和东南石栎(Lithocarpus harlandii);并且2012年优势种相比于1996年生态位重叠程度更高;1996年和2012年胸径(DBH)≥10 cm的乔木树种的总生物量分别为151.03 t和148.53 t,而2012年优势种胸径5—10 cm幼树的总生物量达到10.03 t,增长潜力较大。结果总体上与天目山常绿落叶阔叶混交林演替趋势相吻合,并以此揭示天目山亚热带常绿落叶阔叶混交林群落演替规律提供数据支撑与借鉴。     

亚高山森林自然与人工恢复对土壤涵水能力的影响

西南亚高山原始针叶林被大规模采伐后,在皆伐迹地上营造了大量云杉林进行人工恢复。但关于这些人工林的土壤涵水能力如何,一直没有系统深入的研究与评价。选择川西米亚罗林区系列不同林龄云杉人工林(20 a、30 a、40 a、70 a)为对象,以相邻同龄自然更新恢复的针阔混交林为对照,比较人工林土壤涵水能力随着演替进程的动态及其与自然恢复次生林之间的差异,结合人工与自然恢复后的林地特征(如细根生物量、凋落物储量和土壤有机碳等)和土壤物理结构参数等差异,阐释自然与人工恢复后土壤涵水能力差异的影响因素。结果显示:随着人工林演替,土壤0—40 cm层最大持水量随林龄的增加而降低,但变化不显著,从20年的2200 t/hm~2下降到70年的2138 t/hm~2,年平均下降速率为1.24 t/hm~2;然而在自然次生林中,土壤最大持水量随着林龄的增加呈现出波动式变化,从20年的2142 t/hm~2增加到40年的2565 t/hm~2,到70年又下降为2302 t/hm~2。通过土壤持水特性与林地凋落物贮量、细根生物量和土壤物理结构参数的相关分析表明,由不同恢复途径导致的林地土壤有机碳含量、凋落物特性及细根差异,进而改变土壤物理结构是影响土壤持水性能差异的主要因素。这些结果说明,从土壤持水量角度考虑,在对采伐迹地进行造林恢复时,应尽量避免营造结构单一、高密度的人工纯林,应选择营造针阔混交林的模式进行恢复。     

间伐对落叶松人工林内草本植物多样性及其组成的影响

通过对落叶松人工林间伐林分和未间伐林分林下草本植物的调查以及林下光照条件的测定,分析间伐对林下草本植物多样性、组成的影响及其与光照条件的关系。结果表明,除均匀度指数在春、秋季表现不同外,间伐林分的丰富度指数、多样性指数均高于未间伐林分,说明间伐后草本植物多样性明显增加。依据草本物种在间伐前后出现与否和密度变化情况将其划分为正反应种(间伐后密度明显增加和间伐后新出现的种)、中性反应种(间伐后密度变化不明显或没有变化的种)和负反应种(间伐后密度明显减小和间伐后消失的种),间伐后出现大量新的草本种类,同时在间伐和未间伐林分的共有种中有许多表现为负反应种。在间伐林分中,间伐行和未间伐行的共有种春季有11个、秋季有10个,分别占间伐林分草本总种数的17.74%和15.15%,表明各行草本植物组成差异较大;各指数均呈现了从间伐行到未间伐行逐渐减小的趋势。主要的正反应种、中性反应种和负反应种均表现出与光照具有一定的相关性,且这种相关性与间伐和非间伐林分之间各草本物种与光照的相关性基本一致。