广东古兜山自然保护区蕨类植物多样性对植被不同演替阶段的生态响应

蕨类植物是最早登陆的维管植物,至今仍然是生态系统初级生产力的重要组成部分。它们一方面可以通过改造生态环境影响森林群落发生和发展的过程,另一方面由于它们对生态因子变化的敏感性,其组成的多样性及其对环境的适应组合也随着森林群落发生和发展而不断变化。为了解蕨类植物在群落演替的各个阶段的种类组成、物种多样性格局演变规律及其适应方式的选择,本文选择广东古兜山自然保护区中的草丛、灌丛、次生常绿阔叶林和地带性南亚热带季风常绿阔叶林(以下相对简称“原生林”)等4个处于不同演替阶段的植被类型中的蕨类植物群落进行研究。每一植被类型中选取4个5m×5m代表性小样方进行取样调查,对其主要数量特征、群落的α多样性、β多样性、不同群落间的相似性系数和蕨类植物的种类性质进行了分析。结果表明:随着群落演替的进展,草丛、灌丛、次生林和原生林各阶段植被中:(1)群落之间的β多样性指数逐渐增大,而相似性指数依次降低;(2)蕨类植物的物种丰富度依次增大,而群落的多样性指数、生态优势度和均匀度并不伴随着群落的丰富度呈明显的规律性变化;(3)具革质叶的蕨类、阳生蕨类和进行无性繁殖的蕨类植物在各阶段所占的比例和重要值比重逐渐减少,而具草质叶的蕨类、阴生蕨类和进行有性繁殖的蕨类植物则     

广东石门台自然保护区粘木—甜锥群落特征研究

根据样方调查的结果 ,分析了广东石门台自然保护区粘木—甜锥群落的种类组成 ,区系成分 ,外貌特征和年龄结构。结果表明 ,在 5 0 0m2 样方中 ,有维管束植物 78种 ,分别隶属 46科、64属 ;优势科为樟科、山茶科、壳斗科、茜草科等。热带 -亚热带区系成分在群落中占明显优势 ,具有南亚热带向中亚热带过渡的特点。群落的生活型以高位芽为主 ,群落外貌主要由革质、单叶和中、小型叶为主的常绿阔叶林高位芽植物决定。群落成层现象明显 ,可分为乔木层、灌木层、草本层 ,乔木层可再划分为 2～ 3个亚层。种群的立木结构表明 ,粘木种群已处于衰退状态 ,将来有被其他种群替代的可能。对粘木的保护应采取采种育苗 ,扩大其种植面积的保护措施。     

澳门路环岛灌丛群落的特征

初步分析了澳门路环岛灌丛群落的种类组成及种群的多度、频度、重要值及外貌,结果表明:群落植物种类丰富,种属组成分散,具有典型的南亚热带区系特点。广东蒲桃、豺皮樟、亮叶柃、桃金娘等在群落中占明显优势,但本区灌丛群落均匀性偏低。具有较高丰富度的种类仅占很少部分,可能与乔木缺乏和种群竞争有关。群落的外貌主要是由小型和中型落叶草质及常绿革质、全缘单叶的高位芽植物所决定的。在分析灌丛群落特征的基础上,对其生态保护提出了建议。     

西双版纳热带山地常绿阔叶林蕨类植物的组成及生态特征

根据4个50m×50m样地(400个5m×5m小样方,共计1hm2取样面积)的详细调查及对各样地外蕨类植物区系的采集调查,研究了西双版纳热带山地常绿阔叶林蕨类组成特点及其数量特征等。结果表明:在所调查的5hm2滇南热带山地常绿阔叶林里记录有蕨类植物64种;在生活型组成上,以地面芽和地下芽为主;在叶特征上,以革质和纸质叶居多,叶形以一回羽状和二回羽状叶占优势;在森林群落中蕨类植物有明显的季相变化;在重要值上,狗脊、疏叶蹄盖蕨、苏铁蕨、光叶鳞盖蕨、清秀复叶耳蕨和假稀羽鳞毛蕨的重要值之和占重要值总和的84.02%,其中,狗脊的重要值占重要值总和的1/3以上,它们是该森林群落中占优势的蕨类种类,在生态分布上为该森林群落的"适宜种";研究还发现,勐腊凤尾蕨为该森林群落的确限种。     

坡向差异对广东古兜山自然保护区蕨类植物多样性的生态影响

为揭示坡向差异对蕨类植物多样性的生态影响,作者在广东新会古兜山自然保护区海拔1,000 m以下的中低山植被东、南、西、北4个坡向,分别选取10个5 m×5 m的样方进行调查,分析蕨类植物群落多样性和种类组成的差异.结果表明:(1)东坡(半阴坡)与北坡(阴坡)物种多样性最丰富,而西坡(半阳坡)和南坡(阳坡)相对贫乏;(2)4个坡向的相似性系数均很低(不超过0.5),其中南坡(阳坡)与北坡(阴坡)间种类组成差异最大;(3)反映热量差异的区系地理性质分析显示,热带性质蕨类植物在阳坡占优势,而非热带性蕨类在阴坡占优势,南坡、西坡、东坡、北坡的热带成分比例依次下降;(4)反映光照条件的植物耐荫程度分析显示,阴性种类占优势,阳性和耐荫性种类较少,其阴性蕨类植物的比例依南坡、西坡、东坡、北坡顺序增加;阳性蕨类植物比例最高的坡面是西坡,而最低的是东坡.南坡的比例稍高于北坡.研究结果显示坡向差异对蕨类植物物种及其生态习性的多样性分布格局具有比较明显的影响,蕨类植物多样性可以作为环境和气候变化的一个较好的指示物种.     

福建梅花山自然保护区蕨类植物区系研究

通过野外调查和资料整理,统计分析梅花山自然保护区蕨类植物区系组成和分布区类型,比较其与周边相邻4个自然保护区的蕨类植物区系的相似性。结果表明:(1)梅花山自然保护区共有蕨类植物42科83属189种,科、属组成优势现象明显,区系起源古老。(2)分布区类型在科、属级水平上以泛热带分布和世界分布为主,种级水平以热带亚洲分布、东亚分布和中国特有分布为主,热带亲缘明显,具有由热带向温带过渡的性质。(3)在地理亲缘关系上,梅花山与梁野山的蕨类植物区系联系最为紧密,与圭龙山的关系次之,与热带区系性质较强的南靖南亚热带雨林自然保护区和典型的中亚热带性质的武夷山自然保护区的种子植物区系联系较为疏远,具有从南亚热带向中亚热带过渡的明显特点。     

澳门青洲山白楸+假苹婆+破布叶群落特征研究

采用样方调查法对澳门青洲山白楸（Mallotus paniculatus）＋假苹婆（Sterculia lanceolata）＋破布叶（Microcos paniculata）群落的种类组成、外貌、结构特征、区系和物种多样性进行了分析,结果表明,1700m2样方中有维管植物70种,隶属于42科65属,其中热带性分布属占90.32%,群落属于南亚热带常绿阔叶林植被类型。群落外貌常绿,生活型以藤本高位芽为主（占22.86%）。群落的物种丰富度Magarlef指数为8.78,Shannon-Wienner指数为2.22,Simpson指数为0.98,均匀度Pielou指数为0.52。群落各层次的丰富度、Simpson指数以及Shannon-Wienner指数均表现为下木层〉乔木层〉藤本植物〉草本层,均匀度表现为藤本植物〉乔木层〉下木层〉草本层,表明下木层中组成的种类较乔木层多,优势树种较乔木层明显。     

西双版纳勐腊望天树热带季节雨林蕨类植物组成及生态特征

采用生态学样方调查及统计学方法,研究了云南勐腊望天树热带季节性雨林蕨类植物的组成及生态特征。结果表明:在1hm2(4个50m×50m,含400个5m×5m小样方)面积的样地里,记录有蕨类植物48种13 159株(丛);在生态特征上,40个地生蕨类的盖度之和占调查样地面积的22.45%,缺乏高盖度级种类;黑鳞轴脉蕨、长叶实蕨、多形叉蕨等属高频度级种类;长叶实蕨、多形叉蕨、黑鳞轴脉蕨、毛柄短肠蕨、薄叶牙蕨、思茅叉蕨等种的重要值之和占86.31%,它们是望天树林蕨类植物的典型代表种。生活型组成上,以地面芽植物占优势(达80%)。叶质主要由纸质叶(占54.17%)和草质叶(占27.08%)种类组成;叶形主要由羽状复叶种类组成(89.58%)。与西双版纳相同取样面积的山地常绿阔叶林比较,望天树林蕨类植物的种数及种群数量分别是山地常绿阔叶林的1.55倍及2.23倍。同一地区不同海拔和生境异质性是导致蕨类植物组成不同、种群数量变化的主要原因。该研究揭示了赤道热带北缘热带雨林蕨类植物的组成及生态特征,有利于与其它热带地区蕨类植物作进一步的比较研究。     

广东石门台自然保护区广东松群落的基本特征

应用样方法研究了广东英德石门台自然保护区的广东松群落的物种多样性、区系地理成分和年龄结构。结果表明,在2 000 m2样方中,有维管植物68种,隶属于38科57属,其中有广东松、白豆杉和福建柏3种国家Ⅱ级保护植物。群落的Simpson和Shannon-Wiener多样性指数分别为0.880 7和3.977 3。群落优势科为山茶科、樟科、壳斗科、木兰科和杜鹃花科等,植物科属的地理成分以泛热带和北温带分布型等占优势,体现了南亚热带向中亚热带过渡的特点。种群的立木结构表明广东松无更新幼苗,属于衰退种群,将来可能被阔叶树种群取代。对广东松群落的保护,将有利于群落中多个濒危植物的生存和发展。     

云南哀牢山国家级自然保护区蕨类植物生态地理研究

报道了哀牢山国家级自然保护区蕨类区系有蕨类植物48科、118属、446种(包括变种和变型)。从蕨类植物的垂直分布、东西分布和生态类型的划分等几个方面对哀牢山国家级自然保护区蕨类植物生态进行探讨并得出以下结论:(1)在海拔分布上,蕨类植物有着与不同植被相关的生态适应性,2000~2800 m的中山湿性常绿阔叶林和山顶苔藓矮林地带蕨类植物种类最为丰富,附生蕨类植物占到了该海拔地带蕨类植物总种数的28.5%;(2)东坡有蕨类植物387种,西坡则只有355种,东西坡共有种达295种;(3)哀牢山国家级自然保护区蕨类植物可划分为16个生态类型,本区明显地以阴生植物、亚高温植物和中生植物居多,附生植物种类所占比例大,旱生植物和石生植物种类少等为主要生态特征。哀牢山国家级自然保护区蕨类植物的温度生态类型以亚热带植物种类为主,温带植物和寒温带植物少。     

南亚热带森林群落种-多度的对数正态分布模型研究

通过对地处南亚热带的广东省黑石顶自然保护区森林群落的定点研究结果的分析表明：当用１,２,３,…分组每种个体数ｒ时,５个不同类型的群落样地的种一多度分布的直方图都呈明显的倒Ｊ－形;经Ｐｒｅｓｔｏｎ“倍程（ｏｃｔａｖｅｓ）”法分组ｒ后,其种－多度都服从对数正态分布。由种－多度模型可以推出另一新的模型一个体一多度分布模型,即Ｉ（Ｒ）＝２R0ＳＯＥＸＰ［［１ｎ２）２／４ａ２〕ＥＸＰ｛－ａ２（Ｒ－（ＲＯ＋１ｎ２／２ａ２）］２｝,它也符合对数正态分布。另外,还运用积分方法推导出估计总体（整个群落）中总种数Ｓ*和总个体数Ｉ*理论值的公式,用此公式估计的结果较为合理。     

An arsenic hyperaccumulating fern,Pteris vittata L. (Pteridaceae) broadly affects terrestrial invertebrate abundance

1. The Chinese brake fern (Pteris vittata L.; Pteridaceae) can accumulate up to 27 000 mg kg^?1 dry wt. of arsenic (As) from the soil into its above‐ground biomass. They may use this As to deter invertebrate threats. 2. This study explored how As concentrations [As] in the fern, and in soil associated with the fern, influenced the abundance and composition of various invertebrates. 3. Populations of P. vittata were identified in the field. Soils from the base of the fern and from 3 m away of each plant were collected and pitfall traps were installed. Soil and fern arsenic concentrations ([As]) were measured via inductively coupled plasma mass spectrometry and invertebrates were identified to order and classified by feeding guild. 4. Increased [As] did not affect all feeding guilds and orders equally. For example, individual herbivore abundance did not decrease as [As] increased, but predator abundance did. In many cases, the impact of soil [As] on invertebrates depended on the distance from the fern. Fern [As] also influenced components of the community, but only at 3 m away from the fern. Furthermore, the abundances of many invertebrate groups were higher beneath the fern, where [As] was higher. 5. These results suggest that hyperaccumulated As can impact the invertebrate community, but the defensive benefits of hyperaccumulation are more complex than have been previously described. The authors advocate that future studies examining the potential defensive benefits of hyperaccumulation should do so in a natural setting that incorporates this complexity and invertebrate richness.     

Diatoms and biomonitoring: should cell size be accounted for?

Despite the fact that biovolume calculation is a common procedure in most phytoplankton and periphyton studies, diatom community analyses are usually based on relative abundance data. In a biomonitoring context, a community metric that accounts for cell size could be of interest due to the potential differences that might exist in nutrient uptake between large and small-sized species. This paper addresses the question of whether diatom community analysis should be based on relative abundance, biovolume or cell surface. The results show that although community structure expressed as relative proportion of taxa varied according to the metric used, the ordinations conducted with each metric were similar. The explained percentage of species variance was slightly higher with the relative abundance metric compared to the metrics based on relative biovolume or cell surface area. Partial CCAs showed that each water chemistry variable generally explained a higher portion of species variance when the relative abundance was used. The analyses conducted with two size groups (small and large taxa) expressed as relative abundance and relative biovolume showed similar results. Moreover, our data showed that there is no significant relationship between diatom size and total phosphorus. According to these results, it seems that relative abundance would be the most appropriate metric to use for biomonitoring purposes. The biovolume and cell surface area calculations added substantially to the total analysis time due to the numerous measurements required, but did not improve the variance explained in community structure, and site ordinations were not significantly different. Electronic supplementary material Electronic supplementary material is available for this article at and accessible for authorised users.     

海南岛霸王岭两种典型热带季雨林群落特征

热带季雨林为海南岛的隐域性植被类型,分布在与热带低地雨林相似的海拔范围但生境条件较差的局部地段,在旱季其大部分的乔木种类和个体都会落叶.海南岛霸王岭林区分布着海南岛最为典型且大都保存较为完好的热带季雨林原始林,按照其优势树种可划分为海南榄仁(Terminalia hainanensis)季雨林和枫香(Liquidambar formosana)季雨林两种群落类型.通过对霸王岭林区两种典型的热带季雨林老龄林群落的样地调查,比较分析了其物种组成、大小结构、多样性、季相变化等特征.结果表明:海南岛热带季雨林群落中物种优势度明显,具有明显的标志种--海南榄仁和枫香.海南榄仁群落具有较高的灌木物种丰富度、个体多度及较低的乔木物种丰富度、个体多度和多样性;海南榄仁群落在小径级和低高度级中具有较高的植物个体多度,同时在低高度级中具有较低的物种丰富度,但其它径级和高度级两个群落物种丰富度及个体多度差异均不显著;除灌木落叶物种丰富度海南榄仁群落显著高于枫香群落外,其余各生长型落叶物种丰富度及个体多度两个群落之间均无显著差异;在具刺木质藤本物种丰富度和个体多度上海南榄仁群落与枫香群落差异不显著,但乔木、灌木和木本植物具刺物种丰富度及个体多度海南榄仁群落均显著高于枫香群落.总体来看,海南榄仁群落比枫香群落的季雨林特征明显,是海南岛最为典型的季雨林群落类型.     

The influence of life form on carbon and nitrogen relationships in tropical rainforest ferns

Tropical ferns are characterized by a high diversity of plant life forms, yet there have been few large-scale studies on the functional ecology of these different forms. We examined epiphytic, hemiepiphytic, and terrestrial ferns, and asked whether there are differences in the mineral nutrition and water relations across different growth forms of a diverse assemblage of species. We measured specific leaf area, leaf nitrogen concentrations, and natural abundance of the stable isotopes δ¹⁵N and δ¹³C of 48 fern species from 36 genera across a wide range of habitats at La Selva Biological Station in Costa Rica. We found that epiphytes were significantly different in all measured variables from hemiepiphytic and terrestrial species, and that terrestrial and soil-rooted hemiepiphytes were indistinguishable in all variables excluding SLW. A multivariate analysis revealed that aspects of N nutrition were the most reliable at separating epiphytic species from other life forms. Our study demonstrates that the natural abundance of both C and N as well as N relations and leaf morphology are useful when segregating different plant life forms, and that the N cycle of epiphytic and terrestrial habitats function independently from each other.     

Species Abundance in a Forest Community in South China: A Case of Poisson Lognormal Distribution

Case studies on Poisson lognormal distribution of species abundance have been rare, especially in forest communities. We propose a numerical method to fit the Poisson lognormal to the species abundance data at an evergreen mixed forest in the Dinghushan Biosphere Reserve, South China. Plants in the tree, shrub and herb layers in 25 quadrats of 20 m×20 m, 5 m×5 m, and 1 m×1 m were surveyed. Results indicated that: (i) for each layer, the observed species abundance with a similarly small median, mode, and a variance larger than the mean was reverse J-shaped and followed well the zero-truncated Poisson lognormal;(ii) the coefficient of variation, skewness and kurtosis of abundance, and two Poisson lognormal parameters (σ andμ) for shrub layer were closer to those for the herb layer than those for the tree layer; and (iii) from the tree to the shrub to the herb layer, the σ and the coefficient of variation decreased, whereas diversity increased. We suggest that: (i) the species abundance distributions in the three layers reflects the overall community characteristics; (ii) the Poisson lognormal can describe the species abundance distribution in diverse communities with a few abundant species but many rare species; and (iii) 1/σ should be an alternative measure of diversity.     

琅琊山虫生真菌物种多样性和季节变化

在皖东琅琊山自然保护区设置的20个样方中共采集672份虫生真菌标本,分属于4科8属20种.优势种依次为球孢白僵菌、粉拟青霉、环链拟青霉、布氏白僵菌和玫烟色拟青霉,其中球孢白僵菌占绝对优势,相对多度高达73.8%.选用物种多度、Shannon-Wiener指数H′和Pielou均匀度E对琅琊山虫生真菌物种多样性和季节分布进行研究发现,虫生真菌数量丰富但物种多样性指数较低;夏季虫生真菌菌株最为丰富,均匀度相对较低,随着气温及降雨量的下降,菌株数量急剧下降,均匀度相对较高;不同季节白僵菌属的数量波动大,但拟青霉属波动较小.     

Alien grasses in Brazilian savannas: a threat to the biodiversity

African grasses used as forage are spreading fast in cerrado (Brazilian savanna) patches, probably displacing native species. An analysis of the graminoid species abundance was performed in Cerrado Pé-de-Gigante Reserve (São Paulo State, Brazil), where their relative frequency, density, dominance and the value of importance were assessed in two cerrado forms: cerrado sensu stricto (denser) and campo cerrado (open). Thirty-six transects were determined, along which 3240.5 m × 0.5 m herbaceous samples were taken. Ordination by CCA analysis was performed to detect gradients in the graminoid species distribution, according to shading, distance from the reserve border and aspect. Interspecific associations among the species were tested. A total of 93 species were sampled, predominantly Poaceae and Myrtaceae families. Two alien grasses were found, Melinis minutiflora and Brachiaria decumbens, with very high values of importance. Light availability proved to be the most important analyzed environmental factor related to graminoid distribution, strongly correlated with the abundance of M. minutiflora. Both alien grasses were negatively associated with most native graminoids, suggesting they exert a strong competitive pressure on the native herbaceous community. Attention must be taken to the introduction of alien species in the country.     

The orchid community in the Biosphere Reserve Sierra del Rosario, Cuba

The Biosphere Reserve Sierra del Rosario is located in Western Cuba and two different areas can be characterized: one for tourism and forestry activities, El Taburete (ET), and the other for conservation and research, El Salón (ES). With the aim to know the effect of visitation activities on the orchid community in the Reserve, a comparative study between the disturbed area and the preserved one was undertaken. The field work, held between 2004-2005, consisted on four transects in each locality (10 x 100m, 0.1ha). For each transect, the existing orchid species (terrestrial and epiphytic), kind of phorophytes, and level of occupation were identified. Different analysis were considered: dominance-diversity, Sorensen similarity, the dominance index and the relative abundance of the most abundant species. Our results showed 27 phorophytes species, 20 species in ET (98 phorophytes), and 16 species in ES (76 phorophytes). A total of 22 genus, 26 species and 8 326 individuals of orchids were identified. In ET, 17 genus, 18 species and 5 075 individuals were found, while for ES were 15 genus, 18 species and 3 251 individuals. Both locations have a similarity of species of 57.14%. Oeceoclades maculata, an invasive species, was the most abundant. The most dominant species were Microchilus plantagineus in ES and O. maculata in ET. The dominance in ET was of 81.79%, while in ES of 69.27%. It is important to sketch management plans focused on controlling O. maculata in both areas, and the restoration of the disturbed area.