不同植被恢复模式土壤结构特征与健康评价

对湘西女儿寨流域不同植被恢复类型的土壤结构特征研究和健康评价的结果寝明。荒草灌丛容量最高．人工林土壤容重高于天然林及混交林，对土壤孔隙状况的改善作用表现为林分类型优于荒草灌丛类型．天然林优于人工林，0-20cm土层优于20—40cm土层；土壤团聚体平均重量直径以油桐人工林、杜仲人工林最高．马尾松天然林、毛竹杉木混交林其次．而润楠次生林、荒草灌丛、杉木人工林较低，各层土壤团聚体分形维数值大小排序为：毛竹杉木混交林〉马尾松天然林〉荒草灌丛、润楠次生林〉杜仲人工林〉油桐人工林〉杉术人工林；土壤结构健康综合评价的灰色关联分析结果表明．土壤结构以荒草灌丛最差，油桐人工林最好，其余类型介于两者之间．研究结果可为女儿寨流域及我国类似生态脆弱区的植被恢复与重建提供一定依据和参考．     

重金属污染对土壤酶活性的影响

[目的]探求表征土壤重金属污染的主要指示酶,为重金属污染土壤环境质量评价提供理论依据。[方法]以东北黑土为主要研究对象,采用实验室模拟试验,研究不同浓度重金属Cu、Zn、Pb、Cd单因素污染对土壤中过氧化氢酶、脲酶、转化酶、蛋白酶和脱氢酶活性及微生物群落的影响。[结果]土壤脲酶活性与重金属的污染程度呈良好的负相关关系,土壤过氧化氢酶活性对Cu、Zn含量的增加表现较敏感,土壤转化酶活性对Cu非常敏感。[结论]土壤脲酶活性最适于作为土壤重金属污染的敏感指标。     

不同水生植物对温室大棚鳝池水质指标的影响

为了优化黄鳝生态养殖条件,监测了菹草、空心菜与水葫芦3种不同水生植物对温室鳝池水质理化指标以及浮游动植物量的变化.结果表明,水生植物能有效起到遮阳降温的作用;水体的pH均呈下降趋势,下降幅度大小依次为空心菜、水葫芦、空白对照、菹草;平均溶解氧含量大小依次为空心菜、水葫芦、菹草、空白对照;同时,水生植物种殖可有效抑制浮游动植物的生长.     

罗非鱼养殖池塘底泥微生物群落代谢功能的动态变化

利用传统的平板培养法和Biolog ECO微平板法调查了罗非鱼养殖过程池塘底泥异养细菌数量和微生物群落代谢功能的动态变化.结果表明:底泥异养细菌数量在整个养殖过程中均较稳定,其波动高峰出现在6月份,波动范围为(8.4±5.7)×106～(5.2±4.2)×107CFU/g;池塘底泥微生物群落代谢活性和功能多样性以在各个月份之间的差异性均不显著.此外,还分析了底泥微生物群落的碳源代谢特征,底泥微生物群落对4大类碳源的利用,各月份之间无显著性差异;对不同种类碳源的利用存在差异,对糖类的利用率最高,对氨基酸、脂肪酸、代谢中间产物和次生代谢物的利用率较低.     

龙王山落叶阔叶林群落特征及物种多样性研究

采用丰富度（R1、R2）、多样性（D、H）和均匀度（J1、J2）各2种指数研究龙王山落叶阔叶林的物种多样性。结果表明,龙王山落叶阔叶林植物资源丰富,灌木种数最多,草本植物最少,共计有维管束植物54科91属140种（含变种）;群落层次分明,从上到下,分为乔木层、灌木层和草本层,并有少量层间植物。乔木层和草本层中优势种比较明显,灌木层中各优势种的差异不明显;丰富度指数（R1、R2）,多样性指数（D、H）,均匀度指数（J1、J2）的变化趋势均一致,灌木层＞乔木层＞草本层;t检验结果表明,各个层次之间的物种丰富度和多样性差异性均显著,灌木层的均匀度指数（J1、J2）与乔木层和草本层的差异性并不显著,而乔木层与草本层均匀度差异却相对显著。     

和田河上游不同植物群落土壤理化性质及酶活性分析

[目的]通过调查分析不同植物群落土壤理化性质、土壤酶活性的空间分布,了解生境变化过程中植物群落与土壤变化特征,为塔里木盆地西南地区荒漠生态脆弱区植被的恢复和管护提供理论参考。[方法]以和田河上游垂直河岸带4种植物群落类型(Ⅰ-灰叶胡杨+多枝柽柳+芦苇+胀果甘草;Ⅱ-灰叶胡杨+胡杨+多枝柽柳+芦苇+胀果甘草;Ⅲ-黑果枸杞+盐穗木+芦苇+胀果甘草;Ⅳ-花花柴+芦苇+胀果甘草)土壤为研究对象,采用分层取样方法,分析比较不同植物群落土壤理化性质、土壤酶活性空间分布特征,揭示制约荒漠河岸植物群落生存发展的关键因子。[结果]表明:4种植物群落类型土壤含水率、全盐量、碱解氮垂直分布异质性较为明显。同一土层之间含水率、全盐量差异性显著(P<0.05),群落Ⅳ各层土壤含水率均为最低,而全盐量在群落Ⅰ中最低,群落Ⅲ最高。4种植物群落土壤均呈碱性,pH值介于8.40~8.89,而全磷波动范围在0.53~0.86 g·kg^-1之间,两种指标在各植物群落之间均没有显著性差异(P<0.05)。有机质、全氮、脲酶在群落Ⅰ各土层均为最高,而过氧化氢酶、碱性磷酸酶活性在群落Ⅲ最高。[结论]土壤含水率、土壤密度权重系数较大,对外界环境变化比较敏感,可以作为评价该地区荒漠植被土壤肥力的首要指标。     

辽东山区柞树林不同间伐强度下物种多样性分析

物种多样性是描述森林群落结构及个体组成的一个重要指标。采用Margalef丰富度指数、ShannonWiener多样性指数、Simpson多样性指数、Pielou均匀度指数等几个主要参数对辽宁东部山区柞树林不同间伐强度下植物种类多样性规律进行了研究。结果表明,随着柞树林间伐强度的递增,群落的多样性呈递减的趋势。     

滇中三种人工林群落控制土壤侵蚀和改良土壤效应

通过对人工云南松群落、桉树—黑荆混交林群落、直干桉群落及无林地对照地表径流、土壤侵蚀的观测及林地土壤几个主要理化指标的分析表明 ,地带性植物种云南松形成的人工林群落及桉—黑荆混交林具有好的控制径流和土壤侵蚀的能力 ,对土壤理化性质的改善也有较明显的作用 ,值得在生产中推广。在此基础上 ,论述了不同人工林群落土壤理化性质的改善与土壤侵蚀的控制关系。     

Vertical Changes in Bacterial Communities in Percolating Water of a Japanese Paddy Field as Revealed by PCR-DGGE

Percolating water was sampled from the plow layer and subsoil layer in a Japanese paddy field, and the bacterial communities were compared together with floodwater by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) targeting a partial 16S rRNA gene and subsequent sequencing. The number of DGGE bands ranged from 16 to 28 with no significant differences among the sampling sites and times. Only 2 bands were common for the three sources of water samples. DGGE bands specific for the floodwater samples and percolating water samples from the plow layer were identified, while percolating water samples from the subsoil layer did not show specific bands but displayed common bands to those of the floodwater samples (7 bands) and percolating water samples from the plow layer (1 band). Cluster analysis of the DGGE banding patterns showed a distinct clustering in the samples of percolating water from the plow layer and a closer relationship between the others. These results suggest that the bacterial communities in percolating water changed during downward movement through the plow layer and subsoil layer. Sequences of the DGGE bands specific for the samples of percolating water from the plow layer showed a close relationship with anaerobic bacteria such as iron-reducers or uncultured bacterial DNA isolated from environments that are considered to be less oxic. On the other hand, the sequences of the bands specific for the samples of floodwater and percolating water from the subsoil layer showed a close relationship with uncultured bacterial DNA isolated from freshwater environments.     

Influences of roads and development on bird communities in

Our objective was to improve knowledge about effects of broad-scale road and development variables on bird communities in protected desert landscapes. Bird species richness and the relative abundance or probability of occurrence of many species were significantly associated with total length of roads within each of two spatial extents (1- and 2-km radii), distance to the nearest road, distance to the nearest development, or the two-way interactions of these variables. Regression models reflected non-linear relations, interaction effects, spatial-extent effects, and interannual variation. Road and development effects warrant special attention in protected areas because such places may be important sources of indigenous bird communities in a region.