彭州市龙门山不同地震裸地次生演替初期土壤酶活性研究

地震形成的次生裸地的生态恢复包括植被和土壤的结构与功能恢复两个方面.选取彭州龙门山地震崩塌地、泥石流冲积扇、滑坡体等震后形成的三个典型次生裸地恢复3 a后,对表土(0-30 cm)有机碳、水溶性氮、有效磷和土壤酶活性等性质进行了研究,以评价恢复初期不同次生裸地的土壤恢复状况.结果显示,自然恢复3a,土壤有机碳恢复到原生样地的27％～42％,可溶性碳恢复至原生样地的25％～46％,可溶性氮恢复至原生样地的6％～14％,有效磷恢复至原生样地的21％～83％.土壤酶中,过氧化氢酶活性恢复较快,达到对照样地过氧化氢酶活性的70％以上,而脲酶、蔗糖酶、碱性磷酸酶活性恢复较慢,分别为对照样地的5％～19％,6％～48％,6％～26％,因此地震形成的次生裸地上土壤肥力质量与土壤酶活性的恢复是一个长期的过程.     

Physical extent,frequency, and intensity of phosphatase activity varies on soil profiles across a Douglas-fir chronosequence

In forest soils, the availability of phosphate is largely dependent on phosphatase activity. We used soil imprinting to compare in situ activity and fine-scale distribution of phosphatase on soil profiles located across forest chronosequences of four age classes young (5–6 yrs), canopy closure (24–30 yrs), stem exclusion (61–71 yrs), and older (90–103 yrs) of mixed Douglas-fir/paper birch stands regenerated after fire or clearcutting in southern interior British Columbia, Canada. Chromatography paper treated with a mixture of substrate and colorimetric reagent was applied directly to vertical soil surfaces, accessed through root windows. Stands older than 61 years had both the highest level of in situ phosphatase activity and larger, more intense regions of activity. Bray-extractable phosphorus was negatively related to imprintable phosphatase activity. We compared the changes in phosphatase activity with differences in the ectomycorrhizal fungal (EMF) community that had been documented previously in the same stands. Of 84 ectomycorrhizal fungi found on roots in at least two of the stand-age classes, eight taxa were positively correlated and one taxon (Rhizopogon vinicolor/vesiculosus) negatively correlated with high phosphatase activity. The frequency of three taxa appeared to be positively correlated with larger areas of activity on the soil profiles. By using an imprinting approach, this study was able to demonstrate, for the first time, that in situ phosphatase activity and physical attributes of that activity (i.e., number, size, and relative rates of each area of activity) were related to concentrations of soil nutrients and with the frequency of individual ectomycorrhizal fungi.     

浅议广东森林自然度划分标准

森林自然度反映现实森林类型与地带性原始顶板森林类型的差异程度。是反映森林质量和生态状况的一项重要指标。文章叙述了广东省森林自然度划分标准及实践应用情况。探讨了实践应用中存在的问题，提出了完善划分标准的建议。     

退化羊草草地生态恢复技术的研究

在内蒙古锡林郭勒盟东乌珠穆沁旗对退化羊草草地进行了更新复壮的技术研究,初步探索出了退化羊草草地生态恢复技术和群落演替规律。     

The roles of calving migration and climate change in the formation of the weak genetic structure in the Tibetan antelope (Pantholops hodgsonii)

Geographical barriers and distance can reduce gene exchange among animals, resulting in genetic divergence of geographically isolated populations. The Tibetan antelope (Pantholops hodgsonii) has a geographical range of approximately 1600 km across the Qinghai–Tibet Plateau, which comprises a series of tall mountains and big rivers. However, previous studies indicate that there is little genetic differentiation among their geographically delineated populations. To better understand the genetic structure of P. hodgsonii populations, we collected 145 samples from the 3 major calving regions, taking into consideration their various calving grounds and migration routes. We used a combination of mitochondrial sequences (Cyt b, ATPase, D‐loop and COX I) to investigate the genetic structure and the evolutionary divergence of the populations. Significant, albeit weak, genetic differentiation was detected among the 3 geographical populations. Analysis of the genetic divergence process revealed that the animals gradually entered a period of rapid genetic differentiation approximately 60 000 years ago. The calving migration of P. hodgsonii cannot be the main cause of their weak genetic structure because this cannot fully homogenize the genetic pool. Instead, the geological and climatic events as well as the coupling vegetation succession process during this period have been suggested to greatly contribute to the genetic structure and the expansion of genetic diversity.     

大尤尔都斯高寒草原退化演替序列的划分

采用系统聚类分析法对巴音布鲁克大尤尔都斯紫花针茅(Stipapurpurea)高寒草原进行退化演替序列的划分,并对不同退化草地的植物群落结构进行比较。结果表明,随着草地退化演替程度的加剧,群落结构与主要植物种的优势地位发生明显变化,顶级植被紫花针茅的高度、盖度、密度及地上生物量均有所下降;退化演替模式为:紫花针茅+艹洽草属(Koeleria)→赖草属(Leymus)+委陵菜属(Potentilla)→苔草属(Carex)+马先蒿属(Pedicularis)→艹洽草属+委陵菜属;紫花针茅的重要值可作为划分巴音布鲁克大尤尔都斯高寒草地退化的重要指标;相同等级内各样地间相似性大,不同等级间样地相似性小。系统聚类的结果与各样地相似性比较的结果一致。     

松嫩平原不同演替阶段植物群落和土壤特性的关系

探讨了松嫩草原植物群落演替与土壤化学性质与土壤肥力的关系。结果表明：不同演替群落阶段，其土壤的化学性质和肥力存在一定差异，由于土壤化学性质不同，使群落镶嵌分布，组成植被的复合体。随着植被的退化演替，群落的盖度，高度下降，种类组成趋于简单化，生物量减少，土壤盐碱化程度加重，土壤肥力下降，出现次生盐碱植物群落，群落的生物量与土壤值，含盐量，碱化度呈负相关，与土壤腐殖质和全氮含量呈正相关。     

高山嵩草—苔草草地的植被演替

本文以生态位理论为指导,就广泛分布于青藏高原的嵩草—苔草草地在放牧条件下演替的过程和机理进行了研究,结果表明这类草地在放牧条件下演替有四个阶段:珠芽蓼+线叶嵩草—苔草群落(Ⅰ);线叶嵩草+苔草—垂穗鹅观草群落(Ⅱ);线叶嵩草+苔草—毛茛+甘肃马先蒿群落(Ⅲ);苔草+多茎委陵菜—毛茛+钝叶银莲花群落(Ⅳ);其衰退序列是Ⅰ→Ⅱ→Ⅲ→Ⅳ。封育可使群落中优良牧草的生态体积增大,使草地向进展方向演替。     

南方山区草地植被理论类型及演替导向的研究

根据生态学的基本原理，通过植被与环境条件互作关系的分析，将我国南方山区草地划分为Ｃ型、Ｃ－Ｓ型、Ｃ－Ｄ－Ｓ型、Ｓ型、Ｓ－Ｄ型和Ｄ型（Ｃ为竞争，Ｓ为压力，Ｄ为干扰）等７个植被理论类型，探讨了这几类草地演替（或改良）的主要导向措施，并提出了“导向演替”和“非导向演替”的概念和意义。     

高寒地区草地放牧演替与害鼠密度关系的研究

在定性划分放牧演替的基础上，应用Ｗｈｉｔｔａｋｅｒ的生境梯度分析法，进行了演替阶段的定量校正，根据校正后演替序列的基本数据，应用关联分析分别对害鼠密度与植物群落各特性以及主要植物优势度的相关关系进行了探讨。分析结果表明，植物群落种多样性的早熟禾优势度在各自的关联分析中对害鼠（高原鼠兔）密度的关联度分别是０．８２３和０．８８６。由此，从群落角度说，物种多样性大小是调控害鼠度的主要因子，从植物种类角度