高寒草地土壤有机碳含量同植物功能群数量特征关联度或然性初探

采用逐次回归分析法及主成分分析法,对青藏高原高寒草地不同土地利用方式(草甸、草原、人工草地、农田)的67块样地植物功能群数量特征同土壤有机碳含量的耦合性进行分析,以明晰土地利用格局或植被演替对土壤有机碳同植物群落数量特征的影响.结果表明:青藏高原植物-土壤系统有机碳含量在草地利用模式变化或演替过程中具有较强的解释能力.土壤有机碳含量同植物功能群数量特征关联度的或然性受到草地的利用模式、利用强度和利用历史等因素的影响.人工生态系统土壤有机碳含量同地上植物功能群数量特征之间无明显的耦合关系;健康草地生态系统土壤有机碳含量容易同放牧顶级群落优势种数量特征建立一定的耦合关系.退化草地生态系统土壤有机碳含量容易同提高限制性土壤养分的植物功能群建立耦合关系.     

三江平原毛苔草群落30年物种多样性变化研究

对三江平原1973、1983、2003年3个时期的毛苔草群落的种类组成、频度组成及物种多样性进行分析,并进行了比较研究。结果表明:不同时期毛苔草群落的种类组成差异明显,1973-1983年,毛苔草群落的变化主要体现在物种地位的变化,1983-2003年主要表现为物种组成种类的变化;物种多样性特征的变化表现为1973-2003年,物种丰富度呈下降趋势,物种多样性、均匀性呈先增加而后下降的趋势,优势度与之相反,总体表现均为1973-1983年变化缓慢,而1983-2003年变化较大;物种频度图的分析表明,不同时期毛苔草群落的结构均处于稳定状态,但随着演替进行,群落中有分化和演替的趋势,并且以1983-2003年变化最为明显;通过分析初步认为,毛苔草群落物种组成的变化主要由水位的下降所引起,景观破碎化对物种多样性的影响值得进一步研究。     

不同养殖年份鱼塘底泥细菌群落多样性及演替分析

为探究不同养殖年份的鱼塘底泥中细菌多样性及演替关系,通过构建16S rRN A基因文库,比较分析养殖1年和养殖4年池塘底泥样品细菌的群落构成,分别由养殖1年和养殖4年文库获得145和172个克隆子,香农—威纳多样性指数分别为2．37和2．22,辛普森优势度指数分别为9．36和7．58,覆盖度指数分别为100％和93．3％。 Prolixibacter （34／145）、荚硫菌属（17／145）、浮霉菌属（15／145）和脱硫微菌属（12／145）为养殖1年样品优势菌群,长绳菌属（41／172）、Prolixibacter （31／172）、黄色单胞菌属（22／172）、Cetobacterium （21／172）和噬纤维菌属（15／172）为养殖4年样品优势菌群。养殖1年和养殖4年文库细菌菌群结构在种分类水平上的相似度系数为0．6171。由此可知,养殖池塘底泥中蕴含着复杂的微生物群落体系,长期的积累促使该微生物群落发生了演替。     

Management and restoration of fish communities in Lake Taihu, China

The economic development of the cities around Lake Taihu, China, has caused both environmental changes and ecological succession. The biodiversity of Lake Taihu has declined since 1970. Migratory fish, including anadromous, catadromous and semi-migratory fish, are either extinct or on the verge of extinction in Lake Taihu. Only lake dwellers persist. Several measures have been taken, such as restocking, closed seasons, sanctuaries for enhancement and even introductions to restore some original fish communities. Although these measures have achieved a certain degree of success, increased fishing activities or over-fishing have offset the benefits obtained. Moreover, cultural eutrophication of the lake and the pollution of the waterways connected with the lake are getting worse. This jeopardizes the remaining economically valuable species in the lake. Measures are required not only to control eutrophication and pollution, and to reduce the intensity of fishing, but also to address the wider biodiversity issues.     

沙棘自然演替规律初探

沙棘是阳性树种,通过风、鸟、兽等传播,首先侵入,然后占领地盘,大量萌生形成团块或片状沙棘林,随之从中间开始稀疏死亡,逐渐退出,土壤得到改良肥化,被其他树种侵入代替,再通过风、鸟、兽等传播,侵入新的地点,形成新的沙棘林分,重复以上演替过程。     

Fallow to forest: Applying indigenous and scientific knowledge of swidden cultivation to tropical forest restoration

Rotational swidden cultivation systems, with fallow periods long enough for the regeneration of secondary forests are capable of maintaining forest cover and plant diversity in a dynamic balance in swidden cultivation landscapes. Regeneration of secondary forests through several successional stages and by a combination of coppicing and seedling development is still poorly understood, especially the influence of different swiddening practices and the role of animals as seed dispersers. Swidden cultivators possess a vast knowledge of plants growing in swidden fallows and of fallow dynamics as well. Forest restoration in Thailand has been carried out mainly on the basis of experimental research on the potential of indigenous tree species to promote natural forest regeneration and biodiversity recovery; the so-called framework species. Another viable source of knowledge for forest restoration can be the study of the semi-natural revegetation processes in fallows and the indigenous knowledge of swiddeners of these processes. The research presented here was carried out to attain a better understanding of forest regeneration on fallow swiddens under different swiddening regimes and how it may be applied to practical forest restoration, We investigated the vegetation characteristics of from various stages of secondary succession in fallow swiddens of the Karen and Lawa ethnic groups in the Mae Chaem watershed, Chiang Mai province, northern Thailand. Indigenous knowledge on the use of species and traditional ecological processes in swiddening was recorded by questioning key informants. The data were analyzed and discussed with respect to their application in forest restoration and participatory forest management.     

缙云山次生演替植物群落土壤抗蚀性研究

在重庆缙云山选择典型、有代表性的不同演替阶段的植物群落,进行植被调查和土壤抗蚀性分析。通过因子分析,提出了可反映特征根大部分信息（89.2%）的3类公因子,并以3类公因子对应的方差贡献率为权数计算出10个植物群落土壤抗蚀性的综合得分。其中先锋群落的土壤抗蚀性最好,顶级群落和过渡类型后期植物群落的土壤抗蚀性次之,先锋森林的土壤抗蚀性最差。     

苏北低山丘陵区森林群落次生演替物种多样性分析

对苏北低山丘陵区森林群落次生演替的特征以及空间变化进行了系统研究。结果表明,杂木林多样性最高,物种多样性指数（SD,）1．52～2．39,群落均匀度指数（CEI）0.55～0．89,生态优势度指数（EDI）0.16～0．40;刺槐林多样性最低,SD,0．07～0．17,CEI0．08～0．12,ED10．92～0．97;栎类林和温性松林的多样性分居2、3位。相对而言,苏北东北部低山丘陵区生物多样性较西北部低山丘陵区高。     

Soil degradation processes and plant colonization in abandoned terraced fields overlying pumice tuffs

The state of soil degradation/regeneration in abandoned agricultural terraced fields over pumiceous tuffs has been assessed in this paper. In an initial stage, the relationships between soil types, surface microfeatures as indicators of soil degradation, physicochemical properties, plant colonization and vegetation structure were studied by means of multivariate statistical analyses (PCA, DCA, CCA and TWINSPAN®). Aerial photographs interpretation, DEMs and field surveys allowed us to identify 47 different environments for abandoned fields along 7 altitudinal transects (33 abandoned field terraces). In each study site, an inventory of the existing plant species and of morphological surface microfeatures were also made, by the line‐intercept method. Plant colonization in the field plots studied relates to the variation of soils properties according to a climatic altitudinal gradient. The soil properties most closely related to the abandonment age (decrease of soil salinity and clay content, and increase of soil alkalinity and total organic C and N), have contributed to the growth of plant communities with a high degree of climacity. The protection degree offered to the soils by the different vegetation types as a function of their structure and life‐forms strongly determines the occurrence of the different soil surface microfeatures as indicators of soil degradation or recovery. The acceleration of the early stages of succession by active planting of seeds from shrub species in the lower and upper areas, followed by reforestation in the latter ones, may be the best improvement practices to achieve an effective ecological recovery of the fields and simultaneously to attenuate soil degradation. The reassuming of agriculture may be desirable in those fields placed in middle heights, provided they show the best soil and climate conditions. Copyright © 2006 John Wiley & Sons, Ltd.     

典型草原开垦弃耕后不同年限群落植物多样性和空间结构特征

本文旨在研究不同退耕年限下典型草原群落空间结构和植物多样性的变化特征。以长武王东沟流域不同退耕年限的典型草原为研究对象,采用空间序列代替时间序列的方法,对植物群落空间结构和植物多样性的变化特征进行了调查和研究,旨在为草地恢复和管理提供一定的理论基础。结果表明,随着退耕年限的增加,群落高度、盖度、多样性指数、地上生物量、平均个体大小和禾草类功能群所占比例均显著增加（P<0.05）,而群落均匀度指数、密度均显著降低（P<0.05）。在演替的过程中,群落中主要植物种的优势地位发生了明显的替代变化,由演替初期的冰草（Agropyron cristatum）、散穗早熟禾（Poa subfastigiata）,经过中期的异燕麦（Helictotrichon schellianum）、散穗早熟禾,到演替后期的散穗早熟禾。植物群落的空间结构也发生了显著变化,由初期的高密度、小个体分布到后期的低密度、大个体分布。退耕时间对草地群落的物种组成、空间结构及系统功能等方面均存在显著影响。