Effects of plateau zokors (Myospalax Fontanierii) on plant community and soil in an alpine meadow

Effects of plateau zokors (Myospalax fontanierii) on seasonal above- and belowground plant biomass, plant species diversity, and soil moisture and organic matter were examined at an alpine meadow site in Qinghai Province, People's Republic of China. Above- and belowground biomass increased significantly in areas where zokors were removed or burrow systems were abandoned for 5 years compared with areas that zokors had occupied for >10 years. Biomass of monocotyledons was reduced greatly, but biomass of nonpalatable dicotyledons increased significantly, in occupied areas. Diversity of dicotyledons, monocotyledons, and total plants in unoccupied areas was significantly greater than in occupied or abandoned areas. Vegetation cover and height in occupied areas were significantly less than in unoccupied and abandoned areas. No consistent effect by zokors on soil moisture and organic matter was observed.

神农架植被及其生物多样性与垂直分布格局-兼论中国中、北亚热带植被带的划分

本文主要通过样线法和样方法相结合，进行了大量的群落学调查和分析，分别从植物区系、物种多样性的垂直分布格局和森林群落类型三个方面分析了神农架植被的基本特征及其物种多样性，结果表明： 1．神农架地区具有很高的物种丰富度，有高等植物3，479种，隶属于1，010属，202科。 其中，蕨类植物305种，80属，32科;种子植物3，174种，930属，170科，其中裸子植物32种，19属，6科，被子植物3，142种，911属，164科;单子叶植物501种，175属，21科，双子叶植物2，641种，736属，143科。植物区系属的分布区类型中北温带分布型最多，其次为东亚分布、泛热带分布、东亚北美间断分布、旧世界温带分布以及热带亚洲分布。中国特有成分占5.65%，较全国的8.12%低。温热比(温带分布型(8-11)属数与热带分布型(2-7)属数的比值）为1.200，比全国(0.385)高。 调查样方中共出现高等植物784种，隶属于454属，144科，其中蕨类植物41种，32属，16科;种子植物743种，422属，128科，其中裸子植物20种，14属，5科，被子植物723种，408属，123科;单子叶植物86种，58属，11科，双子叶植物637种，350属，112科。属的分布区类型中北温带分布型最多，其次为东亚分布、泛热带分布、东亚北美间断分布、旧世界温带分布以及热带亚洲分布。温热比为1.52，草本层>乔木层>灌木层分别为2.18、1.76和1.14。 2．神农架植被类型多样，具有常绿阔叶林、常绿落叶阔叶混交林、落叶阔叶林、针阔混交林、亚高山针叶林、硬叶常绿阔叶林和亚高山灌丛草甸等自然植被类型。本文，依据乔木物种的重要值将神农架地区的森林植被划分出了69个类型。用Twinspan将调查的森林群落划分为32组，能基本上反映群落间相似的关系。 3．神农架地区具有完整的植被垂直带谱：海拔900 (1300) m以下为常绿阔叶林带;海拔900 (1300) m～1500 (1800)ⅡI为常绿落叶阔叶混交林带;海拔1500 (1800) m-2000 (2200)m为落叶阔叶林带;海拔2000 (2200) m～2400 (2600)m为针阔混交林带：海拔2400 (2600)m以上为亚高山针叶林带。神农架地区植被的垂直带的分化从总体上比较显著，但由于小生境的异质性和人为干扰，垂直带谱又具有一定的模糊性和次生性。南北坡具有一定的差异，但不十分明显，也说明神农架植被的过渡性。 4．神农架物种多样性的垂直分布格局。神农架的物种多样性与海拔的关系，类似于“中间膨胀”规律(mid-altitude bulge)，在中低海拔处生物多样性最高。通过二次多项式回归拟合，得到如下拟合曲线： 1)海拔与总体物种数：y= _14.445x2+ 34.74lx+42.07，Xd=1.203km; 2)海拔与乔木层物种数：y=-6.9707x2+ 21.334x+0.2004，Xdrl.530km; 3)海拔与灌木层物种数：y=-6.1599x2+ 9.9747x+30.991，Xd=0.8 lOkm: 4)海拔与草本层物种数：y= _3.9907x2+ 10.455x+15.35，Xd-1.308km; 5）海拔与乔木层Shannon-Wiener指数：y=_0.3337x2+ 0.9877x+0.2537，Xd' 1.480km; 6)海拔与灌木层Shannon-Wiener指数：y=-0.1938xz+ 0.422lx+1.2103，Xd=1.089km： 7)海拔与草本层Shannon-Wiener指数：y=_0.1072x2+ 0.294lx+0.9954，Xd=1.372km; x为海拔( km)，y为各物种多样性指标，Xd为物种多样性的最大时的海拔。 从这些拟合曲线中可以看出：总体物种多样性在海拔1200m左右的常绿落叶阔叶混交林带最高：乔木层物种多样性在海拔1500m左右的常绿落叶阔叶混交林带与落叶阔叶林的过渡带最高;灌木层物种多样性在海拔800-llOOm左右的常绿阔叶林与常绿落叶阔叶混交林带的过渡带最高;草本层物种多样性在海拔1300-1400m左右的常绿落叶阔叶混交林带最高。 但物种多样性随海拔变化有许多的起伏和波动。这些波动有些反映了群落的垂直带谱随海拔梯度变化的特点，在垂直带谱的过渡区物种多样性往往较高;有些波动反映了一些特殊的生境，有些反映了人为活动的影响，造成了神农架植被的次生性。因此，影响神农架物种多样性垂直分布的因素有：植被本身的性质和特点、过渡带的特点、生境的异质性和人为活动。 5．神农架植被水平地带性的过渡性。海拔1300m以下的植物属的分布区类型的温热比南坡总是比北坡小，而且相差十分显著，反映了神农架作为植被分界线的价值。神农架南坡的基带植被是常绿阔叶林，因此南坡属于中亚热带。北坡的基带植被，虽然也有常绿树种的零星分布，甚至有小块的常绿阔叶林，完全由于小生境所至，分布的主要类型是常绿落叶阔叶混交林，应属于北亚热带。因此，神农架是中、北亚热带重要的过渡地带。神农架地区中北亚热带的具体分界线宜按照分长江干流和汉水的水岭来划界，即猴子石、大窝坑、神农架、神农顶、老君山一线，南坡属于中亚热带，北坡属于北亚热带。 总之，神农架处于我国中、北亚热带的过渡带，具有过渡带的性质，具有很高的物种多样性，拥有完整的植被垂直带谱，具有多种多样的植物群落及其组成的生态系统。而且，具有我国许多特有植物和珍稀濒危保护植物和许多资源植物。因此，神农架植被在我国植被体系中具有重要的地位，是我国生物多样性最丰富的地区之一，是生物多样性保护的关键地区，也应是生物多样性研究的热点地区。 另外，调查分析了黄山和万朝山植被及其物种多样性与垂直分布格局，结果表明： 6．黄山样方中共出现高等植物259种，隶属于263属，110科，其中蕨类植物14种，II属，8科，种子植物345种，152属，105科，其中裸子植物9种，8属，6科，被子植物336种，144属，99科，其中单子叶植物37种，27属，6科，双子叶植物299种，117属，90科。属的分布区类型中北温带分布最多，其次为东亚分布和泛热带分布，再次为东亚北美间断分布、热带亚洲分布以及旧世界温带分布，与神农架和万朝山也较相似，但热带分布的属更多一些。温热比为1.1875，灌木层>草本层>乔木层，分别为1.3818、1.2609和1.2143。 黄山的森林植被类型有针叶林、常绿阔叶林、常绿落叶阔叶混交林、针阔混交林、落叶阔叶林和竹林。Twinspan将调查的森林群落划分为22组，反映群落间相似的关系，比较清楚和适用。依据乔木物种的重要值将森林植被划分出了34个类型。黄山物种多样性的与海拔的关系不十分明显。黄山植被的垂直带谱不是十分明显，将其垂直带谱划分为：海拔1300m(1500m)以下为常绿阔叶林带;海拔1300m(1500m)-1500m(1600m)常绿落叶阔叶混交林 带;1500m(1600m)以上为落叶阔叶林、黄山松林、山地灌木草丛带。垂直带谱在不同坡向上有差别，东、南、西坡的相似性较大，而北坡与其差别较大。 7．万朝山样方中共出现高等植物490种，隶属于339属，124科，其中蕨类植物21种，18属，11科，种子植物469种，321属，113科，其中裸子植物9种，7属，4科，被子植物460种，314属，109科，其中单子叶植物47种，37属，11科，双子叶植物413种，277属，98科。植物属的分布区类型中，北温带分布所占最多，其次为泛热带分布、东亚分布、东亚北美间断分布、旧世界温带分布以及热带亚洲分布，。温热比为1.3366，草本层>乔木层>灌木层，分别为1.5429、1.4063和1.0645。 万朝山的植被类型包括针叶林、落叶阔叶林、针阔混交林和常绿落时阔叶混交林，但没有典型的常绿阔叶林。依据乔木物种的重要值将森林植被划分出了20个类型。万朝山物种多样性与海拔的关系则不十分明显。万朝山的人为干扰比较强，植被的次生性很大，南、北坡物种多样性随海拔升高的起伏较大。

辽东山区与长白山植物物种多样性比较研究

辽东山区（龙岗山）为长白山余脉，原始林受干扰后形成的次生林是该区森林资源主体，长白山是以原始林为主。通过对两地区植物物种组成、林分结构、物种多样性等方面的比较，可以了解受干扰后处于不同演替阶段的森林物种多样性变化。同时，在一定程度上可以说明人类活动对植物物种多样性的影响。本研究通过地面样地调查的方法，分析长白山地区原始林、次生林和辽东山区次生林植物物种多样性差异，并引入干扰度的概念探讨形成这种差异的原因。通过遥感解译的方法分析两地乔木树种多样性空间分布格局的差异及其沿海拔梯度的变化情况。以期为次生林的恢复、经营，及长白植物区的植物保护提供参考。 主要结论：通过地面调查、比较可知1）Shannon-Wiener指数是物种丰富度和均匀度的综合反映，总体Shannon-Wiener多样性指数原始林大于次生林；乔木层和灌木层多样性：辽东山区（次生林）要大于长白山地区（原始林和次生林，下同），而草本层小于长白山地区。2）不同森林类型之间的比较结果表明：次生林的形成在一定程度上增加了物种丰富度，但受到物种散布方式等因素的影响，物种分布的均匀性较差。 引入干扰度的概念，分析干扰强度对两地物种多样性的影响，可知1）干扰对长白山次生林各层均有影响，且各层变化不一致；对辽东山区次生林的影响，基本表现为受中等水平干扰的林分具有较高的物种多样性和均匀度。2）人为干扰是十分复杂的，且各林型本身具有各自独特的特点，这就决定了干扰强度对不同林型的影响不同，且对同一林型不同层次的影响也不相同。随着干扰强度的增加，如长白山桦木林的总体物种多样性增加，乔木层先增加后降低，灌木层与乔木层相反，草本层变化较小；长白山杂木林的总体多样性、乔木层多样性、灌木层多样性均先增加后降低，草本层变化较小；针阔混交林总体、乔木层、草本层多样性各指数表现不一致，灌木层先增加后降低。 通过遥感影像的解译，分析长白山地区和辽东山区乔木树种多样性空间分布格局，结果表明1）两地乔木树种多样性指数多处于1.4-2.0之间，较高和较低多样性指数所占的比重较小；辽东山区乔木层树种多样性高于长白山地区，这与地面调查的结果相一致。2）长白山地区和辽东山区乔木树种多样性的海拔梯度变化不一致：随着海拔梯度的上升，辽东山区乔木层多样性下降；长白山地区乔木层多样性大致表现为先增加后减少，即单峰分布格局。

青海湖鸟岛地区植物群落物种多样性与土壤环境因子的关系

The study on the relationship between plant species diversity and soil factors in the bird island of Qinghai Lake indicated that this island was a low diversity district,its Shannon-Wienner index and species richness decreased with the increasing soil available K,water soluble salt concentration and pH,and there were significant linear and quadratic correlations between them.Stepwise linear regressions showed that soil available K and water soluble salt were the key factors to estimate Shannon-Wienner index and species richness in this island,respectively,and no correlation was found between species evenness and soil factors.

Effect of plateau zokors on vegetation characteristics and productivity of alpine meadow

This research was conducted on alpine meadow site at Menyuan county, Qinghai Province, People's Republic of China to determine the effects of native, subterranean rodent of Qinghai-Tibet grasslands, the plateau zokors (Myospalax baileyi), on seasonal above-and below-ground plant biomass, plant species diversity and productivity. Both total peaks of above-and below-ground biomass were the greatest (413.600 g/m~2 and 2297.502 g/m~2) in the patch no any plateau zokors colonized by plateau zokors over 10 years in August and October, respectively. Both above-and below-ground biomass were significantly increased in the patches where plateau zokors were removed or the burrow systems were abandoned for five years compared to the patches plateau zokors colonized over 10 years. However, both above-and below-ground biomass in abandoned patches were significantly lower than that in uncolonized patches. Monocotyledonous biomass was reduced greatly, but the non-palatable dicots were significantly increased in colonized patches. The palatable biomass of monocots and dicots were increased in abandoned patches. Total plant species diversity was the greatest in uncolonized patchesand least in abandoned patch. The total net primary production in colonized patches was reduced by 68.98% compared with uncolonized patches. Although the patches were without any plateau zokors disturbance for fives years, the total net primary production just reached 58.69% of the uncolonized patches. The above-ground net primary production in abandoned patches increased 28.74% and the below-ground increased 54.91% compared with the colonized patches. We suggest that plateau zokor-induced changes in plant above- and below-ground biomass and species diversity may lead to further alterations of nutrient cycling and trophic dynamics in this alpine meadow ecosystem.

A Plant Needs Ants like a Dog Needs Fleas: Myrmelachista schumanni Ants Gall Many Tree Species to Create Housing

Hundreds of tropical plant species house ant colonies in specialized chambers called domatia. When, in 1873, Richard Spruce likened plant-ants to fleas and asserted that domatia are ant-created galls, he incited a debate that lasted almost a century. Alth

Species richness in a riparian plant community along the banks of the Xiangxi River, the Three Gorges region

The distribution of vascular plant species richness along an altitudinal gradient and their relationships with environmental variables, including slope, aspect, bank (flooding) height, and river width of the Xiangxi River, Hubei Province, were examined. Total vascular plant species richness changed with elevation: it increased at lower elevations, reached a maximum in the midreaches and decreased thereafter. In particular, tree and herbaceous species richness were related to altitude. Correlation analysis (Kendall's tau) between species richness and environmental variables indicated that the change in species richness in the riparian zone was determined by riparian environmental factors and characteristics of regional vegetation distribution along the altitudinal gradient. The low species richness at lower elevations resulted from seasonal flooding and human activities - agriculture and fuel collection - and the higher. Species richness ill (he midreaches reflected transitional zones ill natural vegetation types that had had little disturbance. These results oil species distribution in the riparian community could he utilized as a reference for restoration efforts to improve water quality of the emerging reservoir resulting from the Three Gorges Hydroelectric Dam project.

Response of Polygonum viviparum species and community level to long-term livestock grazing in alpine shrub meadow in Qinghai-Tibet Plateau

Grazing by domestic herbivores is generally recognized as a major ecological factor and an important evolutionary force in grasslands. Grazing has both extensive and profound effects on individual plants and communities. We investigated the response patterns of Polygonum viviparum species and the species diversity of an alpine shrub meadow in response to long-term livestock grazing by a field manipulative experiment controlling livestock numbers on the Qinghai-Tibet Plateau in China. Here, we hypothesize that within a range of grazing pressure, grazing can alter relative allocation to different plant parts without changing total biomass for some plant species if there is life history trade-offs between plant traits. The same type of communities exposed to different grazing pressures may only alter relative species' abundances or species composition and not vary species diversity because plant species differ in resistant capability to herbivory. The results show that plant height and biomass of different organs differed among grazing treatments but total biomass remained constant. Biomass allocation and absolute investments to both reproduction and growth decreased and to belowground storage increased with increased grazing pressure, indicating the increasing in storage function was attained at a cost of reducing reproduction of bulbils and represented an optimal allocation and an adaptive response of the species to long-term aboveground damage. Moreover, our results showed multiform response types for either species groups or single species along the gradient of grazing intensity. Heavy grazing caused a 13.2% increase in species richness. There was difference in species composition of about 18%-20% among grazing treatment. Shannon-Wiener (H') diversity index and species evenness (E) index did not differ among grazing treatments. These results support our hypothesis.

Changes in plant biomass and species composition of alpine Kobresia meadows along altitudinal gradient on the Qinghai-Tibetan Plateau

Alpine Kobresia meadows are major vegetation types on the Qinghai-Tibetan Plateau. There is growing concern over their relationships among biodiversity, productivity and environments. Despite the importance of species composition, species richness, the type of different growth forms, and plant biomass structure for Kobresia meadow ecosystems, few studies have been focused on the relationship between biomass and environmental gradient in the Kobresia meadow plant communities, particularly in relation to soil moisture and edaphic gradients. We measured the plant species composition, herbaceous litter, aboveground and belowground biomass in three Kobresia meadow plant communities in Haibei Alpine Meadow Ecosystem Research Station from 2001 to 2004. Community differences in plant species composition were reflected in biomass distribution. The total biomass showed a decrease from 13196.96 +/- 719.69 g/m(2) in the sedge-dominated K. tibetica swamp to 2869.58 +/- 147.52 g/m(2) in the forb and sedge dominated K. pygmaea meadow, and to 2153.08 +/- 141.95 g/m(2) in the forbs and grasses dominated K. humilis along with the increase of altitude. The vertical distribution of belowground biomass is distinct in the three meadow communities, and the belowground biomass at the depth of 0-10 cm in K. tibetica swamp meadow was significantly higher than that in K. humilis and K. pygmaea meadows (P < 0.01). The herbaceous litter in K. tibetica swamp was significantly higher than those in K. pygnaeca and K. humilis meadows. The effects of plant litter are enhanced when ground water and soil moisture levels are raised. The relative importance of litter and vegetation may vary with soil water availability. In the K. tibetica swamp, total biomass was negatively correlated to species richness (P < 0.05); aboveground biomass was positively correlated to soil organic matter, soil moisture, and plant cover (P < 0.05); belowground biomass was positively correlated with soil moisture (P < 0.05). However, in the K. pygnaeca and K. humilis meadow communities, aboveground biomass was positively correlated to soil organic matter and soil total nitrogen (P < 0.05). This suggests that the distribution of biomass coincided with soil moisture and edaphic gradient in alpine meadows.

兴山龙门河地区的植物群落与物种多样性研究

龙门河地区地处湖北省的西部，神农架的南坡，处于中亚热带向北亚热带过渡的地带。对其植物与植物群落的研究得到如下结果： 龙门河地区共有维管植物160科724属1737种，其中种了植物140科692属共1686种。其植物区系有显著的温带性，温带分布属共380属，占总属数的54.9%，这可能和该地区的地理位置，海拔及人为活动的影响有关，该地区的植物区系还具有古老性，特有属丰富特点，且有较多的珍稀濒危植物分布。 龙门河地区的植被共划分三个自然植被型共16个群系。在高海拔地区保存有较原始的落叶阔叶林，低海拔地区多为人为破坏后的次生类型。这些植被类型随环境条件的变化呈现较有规律的分布，依照其垂直分布的情况，可以将该地区植被划为三个带，即常绿阔叶林带低于海拔900(-1300)m;常绿落叶阔叶混交林位于海拔900(-1300)-600m之间;落叶阔叶林带在海拔1600(-1300)-2200m之间，无针叶林带在龙门河地区分布。应用TWINSPAN和DCA程序对各调查样地进行数量分类和排序结果说明，植物群落的分布与环境因子明显相关，但排序轴不能用海拔等单个的因子来解释。对各群落乔木层的Gleason丰富度指数，Shannon-Wiener指数及Pielou均匀度指数对比后发现，各种指数在不同的群落之间及不同海拔高度上没有明显的规律，这可能是由于人类活动混淆了群落成分及结构的结果。 锐齿槲栎林是神农架地区一种重要的落叶阔叶林，其分布广泛，保存较好。通过对锐齿槲栎种群大小结构的研究发现，中等大小的锐齿槲栎个体数量较多，幼苗与幼树的数量在不同样地间变化很大，其大小结构分布图中多有一定程度的缺失。锐齿槲栎种群多呈现聚集分布，不同的尺度下其聚集程序不同。在大多数尺度下，幼苗幼树的聚集程度比相同尺度下成体的聚集程序高。幼苗更新是锐齿槲栎更新的一种主要形式，其幼苗的出现与林窗的形成有密切的关系。在锐齿槲栎幼苗成长为幼树的过程中，同于种内与种间竞争的影响。导致了许多幼树的死亡。正是由于林窗形成等干扰因素的影响才使锐齿槲栎幼树得以进入群落上层。

亚热带森林外生菌根真菌的生态学研究

菌根是一种植物营养根与土壤真菌形成的共生体，在自然界中分布广泛。外生菌根真菌是菌根真菌的重要类群，其宿主植物约占陆地植物总数的3%左右。由于外生菌根真菌的宿主植物常常是一些生态系统的优势种和建群种，并且这些真菌还参与了许多森林生态系统的有机和无机元素循环、物种的竞争和共存、生物多样性的维持、生态系统的演替等过程，因而对外生菌根真菌的研究有助于对这些生态系统维持和演替机制的深入理解。本文通过外生菌根真菌的种类鉴定和多样性，外生菌根真菌种群的遗传结构，外生菌根真菌群落的结构、空间格局及植物-菌根真菌空间关系，外生菌根真菌接种对植物生长和竞争的影响等四个方面的研究，使我们对这一地区的外生菌根真菌的种类组成、空间分布和传播规律、年度变化、以及对植物群落组成和多样性的影响等方面，有一个初步了解。 外生菌根真菌的鉴定和种类组成是进行菌根真菌研究的前提之一。在第一章中，主要通过子实体形态分类和分子方法，对大型真菌的种类进行了鉴定。在对东灵山和都江堰森林的调查中分别发现的大型真菌106种和98种，菌根真菌比例分别为44.3%和69.4%，木生真菌比例分别为16%和10.2%。按Fellner的评价标准，两个森林群落均属于健康的生态系统。我们应用ITS-RFLP和ITS序列比较的方法对地上子实体、地下菌根及分离培养的菌种进行了种类鉴定和分析。结果表明，ITS-RFLP可以用来进行外生菌根真菌的种类鉴定，而序列分析能够提供更为可靠的信息。二者的结合，可以使我们建立菌根真菌分子数据库成为可能。 种群遗传结构的研究包括种群中个体的空间分布和亲缘关系等方面，有助于加深我们对种群的生殖和传播方式，菌根真菌与风、雨、动物等生态因子的关系等方面的理解。第二章主要以两个外生菌根真菌种群为例，对种群遗传结构中空间距离与遗传相似性的关系、种群结构的年度变化等方面进行了探讨。正红菇（Russula vinosa）种群具有较高的遗传多样性，每个子实体来自不同的克隆。空间距离-遗传相似性关系和空间格局分析的结果均表明，这一正红菇的种群结构可能是由短距离孢子传播产生的，而不可能是无性生长或长距离孢子传播形成的。在对隐花青鹅膏菌（Amanita manginiana）连续两年的种群结构进行了研究中，种群的每一个子实体也均来自不同的克隆。遗传相似性分析、AMOVA、遗传相似性-空间距离关系的结果均显示，这两年的种群在遗传相似性和种群结构上均具有显著差异。对此的一个合理的解释就是，这一外生菌根真菌种群来说，其个体由有性孢子发育为子实体的时间可能超过一年，因而2001和2002年的个体并非同一种群的连续世代。 外生菌根真菌群落可以定义为在一定地理范围和时间尺度内不同外生菌根真菌种群的组合。对外生菌根真菌群落的研究有助于揭示森林生态系统中菌根真菌与植物、菌根真菌与环境因子、以及菌根真菌之间的相互关系。在第三章中，我们应用点格局的分析方法和二元逻辑回归分析对外生菌根真菌的主要类群，即鹅膏菌科，牛肝菌科和红菇科，的空间格局及其与周围（5×5米样方）树种组成的关系进行研究。结果表明，某些树种与特定类群菌根真菌的子实体出现有负相关，而三个类群的外生菌根真菌在克隆生长上的差异并不是子实体空间分布的决定因素。而在较小尺度上（450平方米样方）研究也表明，三个主要外生菌根真菌类群的空间分布为聚集半径不等的集群分布，并且其空间分布不依赖于木本植物的分布。外生菌根真菌主要类群在空间分布上具有相互抑制的特点，而抑制能力的大小可能与菌根真菌地下菌丝体的分布范围及连续性有关。 外生菌根真菌的盆栽接种实验通常用来验证菌根真菌-宿主植物的相互关系，不但有理论意义，也是大田实验和大规模生产应用的基础。第四章中进行了两个实验，对外生菌根真菌多样性与宿主植物生长的关系以及菌根真菌与植物之间竞争平衡的关系进行了初步研究。在外生菌根真菌多样性对马尾松生长影响实验中，菌根真菌接种并未显著促进马尾松幼苗的生长和生物量积累，不同的菌种与地上、地下生物量的积累存在不同（正或负）的相关关系。外生菌根真菌的多样性水平与马尾松幼苗的针叶数量存在显著的正相关，并且随接种时间的延长相关关系更为显著。外生菌根真菌多样性水平还与马尾松幼苗地下生物量的累积呈显著的正相关关系。在外生菌根真菌对三种植物的竞争平衡和共存的影响实验中，外生菌根真菌接种没有显著促进马尾松幼苗的生长，但对漆树和枹栎幼苗的生长有显著影响。外生菌根真菌接种能够在两个外生菌根真菌宿主植物竞争中降低枹栎对马尾松的优势，在马尾松和漆树的竞争中降低马尾松的优势，并促使枹栎与漆树（一个外生菌根真菌宿主和一个非宿主植物）的竞争处于不稳定状态。 本文首次通过生态学的角度对外生菌根真菌的物种多样性、种群结构、群落中的空间格局、以及外生菌根真菌与植物生长的关系进行了较为全面的研究。在大型真菌的多样性方面，菌根和木生真菌比例的引入可以完善森林生态系统的健康评价体系，而分子数据库的建立使对大型真菌尤其是外生菌根真菌多样性的长期监测成为可能;在种群遗传结构方面，本文验证了红菇属和鹅膏菌属克隆较小的特点，以及红菇属菌根真菌以短距离孢子传播为主的繁殖特性，并首次从生活史特点的角度解释菌根真菌的种群结构的年度差异;在菌根真菌群落的空间格局方面，本文首次应用二元逻辑回归和点格局分析的方法研究外生菌根真菌的空间分布及菌根真菌－植物关系，并发现三个类群的外生菌根真菌在子实体分布上具有相互排斥的特点;在控制实验中，本文首次研究了菌根真菌接种的多样性水平对宿主植物的影响，首次研究了外生菌根真菌接种对三个物种之间竞争与共存的影响。虽然这些研究在很多方面都仅得到初步的结果，但我们希望这些探索可以为今后对外生菌根真菌的生态学研究提供有益的启示。

长白山自然保护区北坡森林结构、植物多样性与碳储量40余年的变化

长白山自然保护区始建于1960年，位于北坡的红松针阔叶混交林森林生态系统是我国东北地区典型温带地带性森林植被之一，面临着全球气候变化和人类干扰的双重影响。 本研究以间隔43年的野外调查数据为基础，对1963年和2006年的长白山自然保护区北坡海拔800~1700m的森林植物群落进行对比分析，得到该区域的森林结构、植物多样性与碳储量的变化特点，讨论森林动态变化与人类活动、气候变化的关系，评价长白山自然保护区的保护效果： 对长白山北坡森林沿海拔梯度的森林结构和植物多样性的分析表明：群落的整体空间格局保存完好，植物种类变化不大，乔木层的建群种的种类基本不变，植物多样性与海拔高度呈负相关关系;林下层植物多样性受小环境影响，与海拔高度无明显相关。 以红松（Pinus koraiensis）针阔混交林、红松针叶混交林和云冷杉暗针叶林三种类型为单元分别研究各森林类型的多样性变化：α多样测度选择物种丰富度、Shannon-Wiener和Pielou均匀度指数，较好体现了样地内发生的多样性变化，灌木层和草本层多样性明显下降，一些稀有种和药用物种消失，红松等原优势物种有衰退趋势，阔叶树比例增大;β多样性测度选取Cody指数，体现出海拔梯度上的植被空间格局细节变化，演替层特别是阔叶树的物种更替变化有向高海拔移动的趋势。 对森林生态系统各层次碳储量进行估算：乔木层和灌木层采用维量法，对灌木层自建生长回归方程;草本层、枯枝落叶层采取收获法;植物细根采取根钻法;土壤采取土壤深度加权法。碳密度估算结果都与前人研究结果相似。各类型植被碳库总碳密度都达到170 t/hm2，远远高于国内平均森林植被碳库密度值44.9 t/hm2。 乔木层43年来的碳储量变化都无显著性差异，但仍表现出：阔叶树种碳储量上升，特别在高海拔类型这种变化更加明显;针叶树种碳储量在暗针叶林内大幅下降;树干的碳库分配比例都有所减少，表明植被碳库正存在向不稳定性方向发展的趋势。针阔混交林和暗针叶林的土壤碳储量，与植被碳库出现相反的变化趋势，整体碳库保持在一个相对平衡的状态。 推测造成这种变化的原因是：禁止砍伐等保护措施的实施，基本保存了乔木层垂直分布格局，而气候变暖使阔叶树种比例大幅增加，采集松籽等人类生产及旅游活动对林下层植被影响破坏较大。提议加强保护区内管理力度和规划，以减缓长白山北坡森林群落的不稳定变化趋势。

Diet and feeding behavior of Rhinopithecus bieti at Xiaochangdu, Tibet: Adaptations to a marginal environment

The diet and feeding ecology of a wild subpopulation of black-and-white snub-nosed monkeys (Rhinopithecus bieti) were studied at Xiaochangdu in Honglaxueshan Nature Reserve, Tibet. This region is climatologically harsher than any other inhabited by non-human primates. Black-and-white snub-nosed monkeys fed on 48 parts of 25 plant species, at least three species of lichens and seven species of invertebrates. The number of food items exploited varied markedly among seasons, with dietary diversity being greatest in spring and summer. In winter, black-and-white snub-nosed monkeys had to subsist on fallback foods such as dried grass and bark. Ubiquitous lichens formed a major dietary constituent throughout the year, contributing about 75% of feeding records. Even though lichens act as a staple, our findings signify that the monkeys at Xiaochangdu prefer feeding on foliage, which is higher in protein content than the former. We provide evidence that black-and-white snub-nosed monkeys are able to cope with an array of food items other than lichens and hence can be regarded as feeding generalists. We discuss the results with reference to previous studies on other subpopulations living in habitats that are floristically more diverse and offer more plant food items than the marginal habitat at Xiaochangdu.

Genetic diversity: Geographical distribution and toxin profiles of Microcystis strains (Cyanobacteria) in China

Twenty strains of Microcystis Kutz were isolated from different freshwater bodies in China to analyze the diversity, geographical distribution and toxin profiles. Based on whole-cell polymerase chain reaction of cpcBA-IGS nucleotide sequence, the derived neighbor-joining (NJ) and maximum parsimony (MP) trees indicate that these strains of Microcystis can be divided into four clusters. The strains from south, middle and north region of China formed distinct lineages, suggesting high diversity and a geographical distribution from south to north locations. Moreover, the results being indicating high variable genotypes of the strains of the Microcystis strains from the same lake show that there is high diversity of Microcystis within a water bloom population. Comparing the results of the present study with those reported for compared with 43 strains of Microcystis from other locations, also reveals Chinese strains have high similarity with those from regions in the North Hemispherical. This suggests that the Microcystis strains in the world might have a geographical distribution. Analysis of 30 strains using the primers MCF/TER and TOX2P/TOX2M showed that there was no correlation between the gene of cpcBA-IGS and the presence of mcy. Toxic strains were founded to be predominant in different water bodies throughout China.

Community structure of small fishes in a shallow macrophytic lake (Niushan Lake) along the middle reach of the Yangtze River, China

This study describes the current status of the small fish community in Niushan Lake in China, and examines the spatial and seasonal variations of the community in relation to key environmental factors. Based on macrophyte cover conditions, the lake was divided into three major habitat types: (1) Potamogeton maackianus habitat, (2) Potamogeton maackianus and Myriophyllum spicatum habitat, and (3) uncovered or less-covered habitat. Fish were sampled quantitatively in the three habitat types by block nets seasonally from September 2002 to August 2003. A total of 10 469 individuals from 27 fish species were caught, among which 20 species were considered as small fishes. Rhodeus ocellatus, Paracheilognathus imberbis, Pseudorasbora parva, Micropercops swinhonis and Cultrichthys erythropterus were recognized as dominant small fishes according to their abundance and occurrence. It was noted that (1) small fishes predominated the total number of fish species in the lake, which reflected to some degree the size diminution phenomenon of fish resources; (2) many small fishes had plant detritus as their food item, which was consistent with the abundance of macrophyte detritus in the lake and implied the importance of detritus in supporting small fish secondary production. Canonical correspondence analysis suggested that the spatial distributions of most small fishes were associated with complex macrophyte cover conditions. Macrophyte biomass was positively correlated with species richness, diversity index and the catch per unit of effort (CPUE) of the fish community. Water depth had no significant effects on species diversity and distribution of the small fishes. Correspondence analysis revealed a higher occurrence of the small fishes and higher abundance of individuals in summer and autumn. Seasonal length-frequency distributions of several species indicated that more larval and juvenile individuals appeared in spring and summer. This study provides some baseline information which will be essential to long-term monitoring of small fish communities in the Yangtze lakes.