Competitive and facilitative relationships among three shrub species,and the role of browsing intensity and rooting depth in the Succulent Karoo,South Africa

Abstract. The nearest‐neighbour technique is used to infer competition and facilitation between the three most abundant species in a semi‐arid region of western South Africa. Relationships among the shrubs Leipoldtia schultzei and Ruschia robusta, which are leaf‐succulent members of the Mesembryanthemaceae (‘mesembs’) and Hirpicium alienatum a non‐succulent Asteraceae, were compared on two adjacent sites with different histories of browsing intensity. Competition was more prevalent and more important than facilitation. The only evidence for facilitation was found at the heavily‐browsed site where the palatable Hirpicium was larger under the unpalatable Leipoldtia. Generally the prevalence and importance of competition was reduced at the heavily‐browsed site. Strong evidence was obtained for intraspecific competition in each of the three species; also, competition was evident between the two mesembs, where Leipoldtia was competitively dominant over Ruschia, although neither species inhibited Hirpicium. Minimal competition between the mesembs and the asteraceous shrub was interpreted in terms of differentiation in rooting depth, and competition within the mesembs, in terms of overlap in rooting depth. The mesembs had the bulk of their roots in the top 5 cm of soil, while the asteraceous shrub had the bulk of its roots, and all its fine roots, at greater depths. The shallow‐rooted morphology of the mesembs is well adapted to utilize small rainfall events, which occur frequently in the Succulent Karoo, and do not penetrate the soil deeply. Modifications of existing methods are applied for analysing nearest‐neighbour interactions.     

紫堇属（Corydalis DC.）植物的种子形态及其分类学意义

在光学显微镜下研究了湖北产紫堇属（Corydalis DC.）15种及2变型的种子形态特征。结果表明,其种子小,近圆形、扁圆形或肾形,黑色或深棕色,具油质体。油质体帽状、扇形、条形或不规则,紧贴种子表面或分离。根据种子表面形态,种子可分为4种类型：（1）表面光滑,如大叶紫堇（C.temulifolia Franch.）、川东紫堇（C.acu-minata Franch.）、巴东紫堇（C.hemsleyana Franch.ex Prain）、北岭黄堇（C.fargesii Franch.）、鄂西黄堇（C.shennongensis H.Chuang）和小药八旦子（C.caudata（Lam.）Pers.）;（2）表面具刺或疣状突起,如阜平黄堇（C.wilfordii Regel）、小花黄堇（C.racemosa（Thunb.）Pers.）、地锦苗（C.sheareri S.Moore）和珠芽地锦苗（C.sheareri S.Moore f.bulbillifera Hand.-Mazz.）;（3）表面具凹点状印痕,如刻叶紫堇（C.incisa（Thunb.）Pers.）、紫堇（C.edulis Maxim.）、地柏枝（C.cheilanthifolia Hemsl.）、蛇果黄堇（C.ophiocarpa Hook.f.et Thoms.）、北越紫堇（C.balansae Prain）和延胡索（C.yanhusuo（Y.H.Chou et C.C.Hsu）W.T.Wang ex Z.Y.Su et C.Y.Wu）;（4）表面具凹点状印痕,并被有疣状突起,如伏生紫堇（C.decumbens（Thunb.）Pers.）。种子大小、形状和表面形态以及油质体形态在种内相对稳定,对一些物种的划分具有较重要的意义。     

基于小波包变换的基因微阵列数据预处理方法

目的:基于阿尔茨海默病微阵列基因表达数据,分析研究微阵列基因表达数据预处理的新的有效方法。方法:首先采用标准差滤波、FSC(特征记分准则)和WPT-SAM(小波包变换-微阵列数据显著性分析)方法对微阵列基因表达数据进行预处理,比较处理后获得的基因数和FDR值;然后采用分类聚类方法对处理后的数据进行分类聚类和分层决策聚类,比较分类聚类结果。结果:标准差滤波和FSC方法获得的初筛基因数据较WPT-SAM方法多,但FDR值也高、后续分类聚类结果较WPT-SAM方法差。结论:WPT-SAM方法在预处理微阵列基因表达数据中,是比较灵活理想的分析方法。     

Molecular phylogeny and taxonomic reconsideration of the subfamily Zapodinae (Rodentia: Dipodidae), with an emphasis on Chinese species

Although the subfamily Zapodinae (Rodentia, Dipodidae) contains only five species, the phylogeny and taxonomy of these species are still being disputed. First, whether Eozapus and Napaeozapus should be treated as independent genera or subgenera of Zapus has been argued for a long period. Second, the subspecific genetic differentiation of Chinese jumping mouse (Eozapus setchuanus) has not been studied in detail, neither from morphological nor molecular aspects. In this study, the phylogenetic relationship among all the five species of Zapodinae was reconstructed using DNA sequence data from the mitochondrial cytochrome b gene and the nuclear interphotoreceptor retinoid binding protein gene. Bayesian inference, maximum parsimony and maximum likelihood analyses were conducted. The results showed that two major clades could be recognized within Zapodinae. Eozapus setchuanus, is the species endemic to China, strongly formed a monophyletic clade. In the other clade, genus Zapus received significant support in all analyses to be the sister group of the genus Napaeozapus. By comparing genetic distances among these three genera, we conclude that both Eozapus and Napaeozapus should be considered as valid genera rather than subgenera of Zapus. Furthermore, we observed that the two subspecies of E. setchuanus did not form reciprocally monophyletic groups, thus the traditional taxonomy which divided E. setchuanus into two subspecies based on only one morphological character was questionable.     

Monitoring of marine benthic communities and taxonomic resolution: an approach through diverse habitats and substrates along the Southern Iberian coastline

Studies conducted along the southern Iberian coastline validate macrobenthic community analyses at taxonomic levels higher than that of species. Twelve studies on littoral benthic communities, carried out by the same research team, were selected spanning both a variety of sampling strategies (spatial, temporal, spatio-temporal) and substrate/habitat types (sediment, rock, algae). In order to establish differences between the results obtained at the taxonomic levels of species, family and order, similarities among stations were calculated using Spearman’s coefficient for ranges. A subset of three studies was selected to investigate possible differences in ‘best-explaining’ environmental variables with taxonomic level. The environmental variables selected at species level were the same as those found at levels of family and order. It is concluded that studies at the different levels of taxonomic resolution (species, family, order) lead to similar results both with regard to relative community distributions and the environmental variables associated with these. The importance of this result for monitoring similar benthic communities is discussed.     

Phylogenetic overview of the Boletineae

The generic and sub-generic relationships in the Boletineae (Boletales) were studied using nuclear large subunit (nuc-lsu), translation elongation factor 1-alpha (tef1), and DNA directed RNA polymerase largest subunit (RPB1). The Boletineae, with the exclusion of Hydnomerulius pinastri, was strongly supported and the status of the families Boletaceae and Paxillaceae is discussed. Members of the genus Boletus are found throughout the phylogeny, with the majority not closely related to the type species, Boletus edulis. Many of the traditional, morphologically defined genera are not supported as monophyletic and additional sampling and taxonomic revisions are needed. The majority of the Boletineae are confirmed or putatively ectomycorrhizal (ECM), but two putatively mycoparasitic lineages (one lineage of Buchwaldoboletus lignicola and Chalciporus piperatus and the second Pseudoboletus parasiticus) are strongly supported.     

Consistency and variation in kelp holdfast assemblages: Spatial patterns of biodiversity for the major phyla at different taxonomic resolutions

The focus of this study was to measure natural spatial variability in the biodiversity of fauna inhabiting kelp holdfasts in northeastern New Zealand at several spatial scales: from meters up to hundreds of kilometers. We wished to test the hypothesis that multivariate variation and biodiversity would vary significantly at different spatial scales in different ways for the major phyla in the holdfast community (Arthropoda, Annelida, Mollusca and Bryozoa). Biodiversity was considered in terms of richness, total abundance, structural composition (as measured by the Bray-Curtis dissimilarity measure) and taxonomic breadth for each major phylum and for the assemblage as a whole. We also examined the effect of taxonomic resolution on multivariate patterns. Species richness and total abundance increased with increases in holdfast volume. Multivariate variation was greatest at the smallest spatial scale for all phyla, but different phyla showed different patterns of multivariate variation at different spatial scales. Variations among locations at the largest spatial scale were primarily due to differences in the composition and richness of bryozoans and molluscs. Location effects became less and less distinct with decreases in taxonomic resolution. There were very few significant differences in richness or abundance for holdfasts of a given volume, taxonomic breadth did not vary significantly across locations, nor did the proportional abundances of phyla. These consistencies across large spatial scales in the absence of environmental impacts and results from other studies suggest that holdfast communities in New Zealand systems would provide a useful model assemblage against which future impacts may be detected as changes in proportions of component phyla. In addition, high variability detected at small and large scales at the species level, especially for bryozoans and molluscs, suggest that these communities may also provide unique opportunities for studying and understanding sources and functions of marine biodiversity.     

龙胆科獐牙菜属新分类纲要

獐牙菜属是龙胆科中的一个大属,广泛分布于亚洲、北美洲、欧洲和非洲.本文报道獐牙菜属下的两个新组(sect.Montana和sect.Echinulata)和七个新系(ser.Repentes,ser.Kilimandscharicae,ser.Coombosae,ser.Japonicae,ser.Swertopsis,ser.Pumilae和ser.Abyssinicae).同时对獐牙菜属中的一些类群进行了分类修订,本分类纲要将被獐牙菜属世界专著采用.     

绢蒿属8种植物果实微形态特征及其分类学意义

为寻找绢蒿属系统学的新证据,应用解剖镜和扫描电镜对我国8种绢蒿属植物的果实微形态特征进行了比较观察。结果表明,绢蒿属8种植物果实形状相似性较高,呈倒卵形或长倒卵形,直或稍弯曲;果脐圆形,常偏向一侧;顶端中央均可见花柱残留物,边缘具衣领状环;果实表面纹饰为搓板状和不规则皱褶纹饰。这些果实微形态特征中,果实的表面纹饰具有一定的差异,特别是次级结构,可作为绢蒿属植物区分种的参考性状之一。