Relationships between floristic gradients in a primary succession

Abstract. Correlations between five floristic gradients at small spatial extents (10 - 20 m) and one successional gradient over a larger spatial extent (1.5 km) are analysed. Floristic data (62 taxa) were sampled on five terminal moraines of known age deposited after the ‘Little Ice Age’ (1750–1930). The floristic gradients on the moraine ridges were sampled by two or three transects on each moraine, and the successional gradient by 114 plots on all moraines. The sequential orders of species were determined by constrained and unconstrained Correspondence Analysis. The similarities between species order on the successional gradient and the exposure gradients at the same age were tested against the null hypothesis of no correlation. The null hypothesis was rejected using both Monte Carlo permutation tests and Spearman's rank correlations, except on the oldest moraine. Here a closed canopy has developed, which eliminates the environmental variability associated with ridge morphology. The similarity between the successional gradient and the moraine-ridge gradients is attributed to variation in environmental severity, mainly caused by glacier wind and related factors such as temperature and moisture. Similarity was highest on the moraines in the middle of the glacier foreland, which have many successional stages present and have a relatively exposed relief. The distribution of growth/life-forms along gradients of small spatial extent are comparable to the successional gradient, but lichens, herbs and graminoids differ in their behaviour. The resemblance between species gradients at a small spatial extent and species gradients on a larger spatial extent is interpreted as an ecological self-similar pattern, where young and old substrate are linked to exposed-xeric and protected-mesic habitats, respectively.     

Vegetation‐environment relationships in Atlantic European calcareous grasslands

Abstract. The relationship between vegetation and environment was investigated for calcareous grasslands in a region in the west of Spain, France, Britain and Ireland defined by climatic criteria. Vegetation was sampled using objective methods and data collected on soils, land cover, location and management. Climate data were obtained from an available database. Examination of the first axis of vegetation variation as defined by Detrended Correspondence Analysis (DCA) showed a gradient from the Irish and British samples to those from France. The Spanish samples formed a separate group on the second axis. The species composition along the gradients is discussed. Correlations between the vegetation gradients and environmental variables were determined. The strongest correlations with the first DCA axis were for temperature, latitude, soil organic matter, grazing and land cover. The second DCA axis was highly correlated with rainfall, altitude and land cover. The third and fourth DCA axes were more difficult to interpret but appeared to be related to land cover. The results indicate that climate factors are important at this scale, but should not be considered in isolation and that factors relating to land cover and management should also be taken into account.     

Effects of soil erosion on the floristic composition of plant communities on marl in northeast Spain

Abstract. This study explored the validity of three responses of vegetation to increased soil erosion: reduction of vegetation cover, number of species and reduced substitution of species. 201 relevés, including edaphic and geomorphological data, were surveyed in the intensely eroded Eocene marls of the Prepyrenees (NE Spain). Changes in plant species’ presence in relevés from different degradation stages were compared. The level of vegetation degradation was defined as the total phanerogam cover which, in the studied area, was correlated to the degree of soil erosion. The considered trends were validated. Reduction of phanerogam cover and species number were gradual from low to high‐eroded areas. Vegetation degradation explained 48% of the species number variance. In the later stages of degradation a significant substitution of species was not observed, only a lower frequency of occurrence of several species that appeared in the whole set of relevés. Through the process of degradation, 47% of species displayed significantly reduced frequencies as degradation increased, none showed a significant increase in frequency. It is concluded that there are no characteristic species in these plant communities that survive in the severely eroded marls. Among the few species that had increased in frequency, most only colonised favourable micro‐environments.     

中国美登木属的新分类群

本文拟定中国美登木属4新种1新等级,它们是:广南美登木M. guangnanensis H.Shao,蒙自美登木M. mengziensis H.Shao,易门美登木M. yimenensis H.Shao,树状美登木M. arboreus H.Shao和疏刺刺茶M. variabilis(Hemsl.)C.Y.Cheng var.inermis(C.Y.Cheng et W.L.Sha)H.Shao。     

云南寸金草新变型

本文发表寸金草一新变型,白花寸金草Clinopodium megalanthum f.leucanthum.     

四川串珠藻属一新种

发表了四川串珠藻属一新种,即彭州串珠藻(Batrachospermum pengzhouense S.L.Xieet Z.X.Shi)。     

昆明地区早寒武世三叶形虫新属——Panlongia Liu et Luo gen. nov.

简述早寒武世关山动物群的研究现状及重要意义。重点描述该动物群中一三叶形虫新属PanlongiaLiuetLuogen.nov.及其两个新种:即个体小、拥有等大的头甲和尾甲、边缘没有明显突出刺状物的PanlongiatetranodusaLiuetLuogen.etsp.nov.及头甲后侧和尾缘具刺的PanlongiaspinosaLiuetLuogen.etsp.nov.。三叶形虫在关山动物群中的首次发现为寒武纪生命大爆发以及古地理、古板块恢复的研究提供了有益的证据。     

小叶栎一新变种

本文发表了小叶栎一新变种, 即临安栎Quercus chenii Nakaivar.linanensis M.C.Liu et X.L.Shen, var.nov.。     

A Study on the Genus Melocalamus Benth. (Bambusoideae) from China

Melocalamus Benth. consists of five species. Through a comprehensive study of history, morphology, and all specimens available, the authors confirm the occurrence in China of M. compactiflorus (Kurz.) Benth. et Hook f., the type of the genus, and two species, M. scandens Hsueh ct Hui, M. fimbriatus Hsueh et Hui, are described as new. A key to speciesis provided.     

The Chemical Principles from the Female lnftorescences of Typha angustata

Seven crystalline compounds have been isolated from the female inflorescences of Typha angustata Bory et Chaub. They were identified as vanillic acid (Ⅰ), E-p-hydroxy- cinnamic acid (Ⅱ), Protocatechuic acid (Ⅲ), E-Pro-penoic acid-3- (4-hydroxyphenyl)- 2,3-dihydrohypropyl ester (Ⅳ), Succinic acid (Ⅴ), p-hydroxybenzaldehyde (Ⅵ) and D-mannitol (Ⅶ). (Ⅳ) is a new compound. (Ⅰ), (Ⅱ), (Ⅲ) and (Ⅶ) were attained for the first time from Typhaceae.