新疆喀纳斯旅游区森林群落数量分类与排序

采用双向指示种分析法(TWINSPAN)和除趋势对应分析(DCA)对新疆喀纳斯旅游区森林群落进行了数量分类和排序.结果表明:①采用TWINSPAN等级分类方法,将森林群落划分为9个类型;②TWINSPAN和DCA相结合应用能较好地反映出各森林群落之间以及森林群落与环境之间的关系;③DCA排序第一轴从左到右,湿度在逐渐增大,第二轴从下到上,气温逐渐降低,沿对角线方向,海拔逐渐升高.影响喀纳斯旅游区森林群落类型和植物种分布格局的主要环境因子是海拔梯度、水分和热量.     

脱氧胆酸处理对大鼠肌肉卫星细胞的影响

肌肉卫星细胞是组织特异性干细胞,负责骨骼肌的生长和再生。尽管卫星细胞的发现已有50多年的历史,但肌肉卫星细胞的维持培养仍是一个难以解决的问题。本研究使用脱氧胆酸(deoxycholic acid,DCA)处理肌肉卫星细胞,结果发现,50μmol/L脱氧胆酸能显著促进肌肉卫星细胞的增殖。Western blotting检测发现50μmol/L DCA能促进细胞内β-catenin表达水平的持续增加。处理6 d后的细胞仍然保持着肌肉卫星细胞的成肌能力。     

五台山旅游对植被影响测量方法的比较

研究旅游对植被影响的测量方法对于评价景区生态环境质量具有重要的意义。目前主要有两种不同的方法。第1种方法是利用传统生态学上植物的重要值来计量;第2种方法是利用景观重要值、物种多样性、群落结构比、耐阴种比值、伴人种比值和旅游影响系数来测量。以五台山为例,采用TWINSPAN和DCA对这两种测量方法进行了比较,它们的结果反映了不同的生态信息。在TWINSPAN中,第1种方法的结果主要反映了不同种群和群落的生态特性;第2种方法的结果主要反映了旅游开发与植被景观之间的生态关系。在DCA中,第1种方法的结果主要反映了不同植物群落类型与自然地理因子之间的生态关系以及不同类型之间的空间格局;第2种方法的结果主要反映了旅游干扰下不同植被景观类型的格局规律。与第1种方法相比,第2种方法在旅游与植被的研究方面则更为合理和科学。     

五台山景区湿地植被的数量分类和排序

利用双向指示种分析方法(TWINSPAN)和除趋势对应分析方法(DCA)对五台山清水河湿地植被进行了数量分类和排序.结果表明:1)TWINSPAN将57个样方分为牡蒿群落、鹅观草群落、地榆+委陵菜群落、水蓼+东方蓼+薄荷群落、水蓼+酸模群落、北水苦荬+东方蓼群落.2)DCA第1轴主要反映了人为干扰程度因子;DCA第2轴主要反映了海拔因子.在DCA图中,湿地植被相应地沿对角线从旱中生的群落类型逐步向湿生群落过渡.3)TWINSPAN和DCA分析结果具有一致性,它们都客观地反映出人为干扰与湿地植被之间的生态关系.     

山西果园秋季杂草群落数量分类和排序分析

通过野外调查,应用双向指示种分析法(TWINSPAN)分类和无趋势对应分析法(DCA)排序,对山西省农业科学院果树研究所果园秋季杂草群落进行了数量分类和排序分析。根据TWINSPAN分类结果,并结合生态特性,将所调查的果园69个样方划分为12个群丛,论述了各群丛的群落学特征。TWINSPAN分类结果较好地反映了杂草群落类型与环境梯度之间的关系,并在DCA二维排序图上得到较好的验证。DCA排序进一步说明了群系的分布格局与土壤养分、土壤水分和海拔的密切关系。结果表明,组成果园杂草的种群对群落生境具有指示作用,能客观反映群落的生境特征。     

The effects of fire on the regeneration of a Quercus douglasii stand in Quail Ridge Reserve, Berryessa Valley (California)

Wildfire is an important element in the dynamics of the blue oak (Quercus douglasii) stand. We evaluated the effect of fire in the regeneration of a stand in Quail Ridge. This protected area is located on a peninsula formed by the flooding of Berryessa Valley (California) which has helped it maintain many elements of the native flora. Major vegetation types are blue oak woodland and forest (Q. douglasii, Fagaceae), chamise chaparral (Adenostoma fasciculatum, Rosaceae), and grasslands. In the blue oak stand, 14 plots were randomly located: seven in the burned area and seven outside of the burned areas (control). The effect of fire on sexual regeneration, asexual regeneration, mortality and species composition was analyzed. The fire caused changes in canopy cover, soil cover and litter cover. Asexual regeneration was significantly favored by the fire, but the effect on sexual regeneration was not significant. Fire caused a significant reduction in the basal area of Q. wislizeni and Arctostaphylos manzanita and a reduction in the density of Heteromeles arbutifolia. We concluded that fire does not have a significant effect on the sexual regeneration of Q. douglasii or Q. wislizeni. Fire does stimulate asexual regeneration in both species of oaks, but grazing reduces the regenerative effect of fire. Fire increases regeneration of Arctostaphylos manzanita and Heteromeles arbutifolia by stimulating asexual and sexual regeneration. The occupancies of these chaparral species are further enhanced by their lower palatability compared to both species of oaks.     

广州市不同土地利用方式下冬季土壤动物群落结构的研究

对广州市越秀区和天河区3种土地利用方式(绿地、林地、农田)下、6种不同样地(人民公园东部绿地、天河体育中心广场绿地、华南植物园、华南农业大学树木园、郊区岑村农田和郊区凤凰街农田)中小型土壤动物群落的数量和结构组成、分布及其变化规律进行了研究。调查期间共获得中小型土壤动物1 365个,共25个类群,分别隶属于7门16个类群,优势类群为线虫纲(Nematoda)、蜱螨目(Acarina)和弹尾目(Collembola),共占总捕获量的83.44%。不同样地生境中土壤动物的类群组成以及个体数不同。各样地土壤动物群落复杂性指数(C)以华南植物园为最高,达2.822,人民公园绿地为最低。观测样地中小型土壤动物表现出明显的表聚现象,垂直分布有明显差异,类群数和个体数随深度增加而减少。群落排序的结果显示,土壤动物群落对人类活动干扰的响应有所不同,其中倍足纲(Diplopoda)和石目(Archaeognatha)这两类土壤动物为稀有类群,仅在观测的林地类样地中有分布,对干扰最为敏感,可用于指示城市化进程S中土地利用类型的变化。     

汾河太原段河温滩草地植被的数量分类与排序

采用双向指示种分析法和除趋势对应分析法对汾河太原段河漫滩草地植被做了分类和排序研究，结果将汾河太原段草地群落划分为17个群系，并论述了各群系的特征。DCA排序进一步说明了群系的分布格局与土壤水分、质地和人为干扰的密切关系。种的DCA排序结果证明对群落生境有明确的指示作用，能客观反映群落的生境特征，此外，还讨论了群落的演替趋势。     

Vegetation development patterns on skislopes in lowland Hokkaido, northern Japan

The Japanese montane zones are usually covered with well-developed forests, and most ski resorts are constructed there. Therefore, the construction of skislopes requires the destruction of forest ecosystems. To detect vegetation development patterns on skislopes, I assessed vegetation on seven skislopes in the lowland of Hokkaido Island, Japan, using 155 2 m×2 m plots. The surrounding vegetation was mostly consisted of broad-leaved forests with a floor of dwarf bamboo, Sasa senanensis. The skislopes were established 5-28 years before the surveys by scraping off the topsoil and subsequent artificial seeding. The data of vegetation analyzed by TWINSPAN resulted in six different grassland types: (A) Miscanthus sinensis-Hypochaeris radicata, (B) introduced herbs with low richness, (C) introduced herbs, (D) Artemisia montana, (E) M. sinensis-Pueraria lobata-A. montana, and (F) Solidago gigantea var. leiophylla. H. radicata and S. gigantea var. leiophylla were alien species. Vegetation dominated by introduced grasses for erosion control, such as Dactylis glomerata and Poa pratensis, should be initial vegetation on the skislopes. Most tree pioneer species established in the vegetation type A, that was most natural vegetation in the skislopes. Type A seemed to proceed from types B and C, and species richness was the highest. Therefore, this type should be preferable for the management and restoration of skislope vegetation. Type D established on newer skislopes, while types E and F established on older skislopes. Results including detrended correspondence analysis suggested that those vegetation types D-F proceeded to distorted succession, i.e. biological invasion changed native successional sere. Based on these results, I recommended that the restriction of alien invasion and careful monitoring on M. sinensis grasslands are required to restore the natural vegetation.     

川西北高寒草地退化演替群落的数量分类与排序

在野外植被调查的基础上,应用TWINSPAN分类和DCA排序法,对川西北高寒草地退化演替群落进行了多元分析.根据TWINSOAN分类结果,并结合生态特性,将所调查的45个样方植被分为12个群丛,论述了各群丛的群落学特征.DCA二维排序图较好地验证了TWINSPAN的分类结果,第1轴主要反映了植物群落所在环境的水分条件梯度,第2轴基本反映了高寒草地不同退化的梯度.