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1. The correlation between climatic variables and past (up to 20 years) growth was studied in seven circumarctic populations of the moss Hylocomium splendens, using retrospective analyses of growth. We hypothesized that relationships between growth and climate would be simpler in an ectohydric moss than in higher plants and that the moss could provide high signal-to-noise ratios of responses to climatic variation.
2. Growth parameters of the moss were strongly correlated with early summer temperatures and with the length of the growing season. Annual segment mass, growth rates and degeneration rates were highest at the mildest subarctic sites and lowest at the high arctic site. In contrast, 'longevity' (age of the oldest segment) increased at the climatically harsher sites.
3. Between-year growth variations at two contrasting sites were significantly correlated with June and July temperatures and, to a lesser extent, with early-season precipitation at one of the sites.
4. The moss currently tolerates a wide range of climates and large interannual variations in temperature and is likely to be at risk from climatic change only at the southern edge of its range.
5. The climate-change component most likely to affect the growth of H. splendens in the Arctic and Subarctic will be a lengthening of the growing season and in increase in early summer temperatures provided that moisture is not limiting.
6. Hylocomium splendens is a suitable species for monitoring climatic change at a circumarctic scale.  相似文献   

3.
Different numerical techniques were used to detect and describe the major ecological-biogeographical patterns of vascular plant distributions at the meso-scale level in a subarctic region in Finland. The distribution patterns of 231 native taxa in 362 1 km2 grid squares of the Kevo Nature Reserve were analysed by two-way indicator species analysis and detrended correspondence analysis, and were subsequently related to twenty-eight geographical, topographical, geological, and vegetational variables using simple discriminant functions and canonical correspondence analysis with associated Monte Carlo permutation tests.
The floristic variation detected reflects variations in environmental factors operative at the regional and local scales. No major broad-scale coherent geographical patterns were detected; instead, the spatial distribution of the grids with a similar floristic composition shows a scattered distribution. All the numerical techniques reveal a major gradient from alpine areas to lowland sites with rivers and rocky outcrops, and the most important explanatory variables for predicting the main floristic variation are all associated with altitude. The floristic patterns represented by the second ordination gradient mainly correlate with the abundance of mires. Partial ordinations indicate that both the geographical and geological variables explain relatively little of the species distributional patterns.
Although the meso-scale approach reveals much about the plant-environment relationships in the study area, the floristic variation appears to be determined mainly by fine-scale factors. In the most heterogeneous grids, the grid size used fails to detect accurately the ecological patterns of the species present.  相似文献   

4.
Our work aims to investigate whether herbaria resources can be used for the extension of Arctic dwarf shrub chronologies. The current use of herbaria reaches far beyond their initially aims; among the new applications, phenology observations and conservation biology can be mentioned. However, to this date, no studies on the use of herbarium specimens for dendrochronological research have been published. Examples of perennial plants from herbarium sheets that could potentially be used for such studies are dwarf shrubs, samples of which often consist of whole specimens, including the root system, the root collar and branches. Here, we present a protocol for the selection and processing of historical material. Based on the collections from Kew and Copenhagen, which are among of the largest herbaria with Arctic plants, a database of 25 areas from the Atlantic sector of the Arctic was created. Material from the following most common species was collected: grey willow (Salix glauca L.), polar willow (Salix polaris Wahlenb.), dwarf willow (Salix herbacea L.), net-leaved willow (Salix reticulata L.), arctic willow (Salix arctica Pall.), mountain avens (Dryas octopetala L.), dwarf birch (Betula nana L.). We present the preliminary results of a case study using historical samples of Salix arctica from the Thule (Qaanaaq) area, NW Greenland. Dwarf shrubs can commonly reach the age of 80–100 years or beyond, while herbaria resources may allow the extension of such series over the last centuries. Therewith, these resources may provide an excellent proxy data source on the changing natural environment beyond the northern and upper tree limits, where well-replicated proxy time-series remain sparse.  相似文献   

5.
The pace of climate change in the Arctic is dramatic, with temperatures rising at a rate double the global average. The timing of flowering and fruiting (phenology) is often temperature dependent and tends to advance as the climate warms. Herbarium specimens, photographs, and field observations can provide historical phenology records and have been used, on a localised scale, to predict species’ phenological sensitivity to climate change. Conducting similar localised studies in the Canadian Arctic, however, poses a challenge where the collection of herbarium specimens, photographs, and field observations have been temporally and spatially sporadic. We used flowering and seed dispersal times of 23 Arctic species from herbarium specimens, photographs, and field observations collected from across the 2.1 million km2 area of Nunavut, Canada, to determine (1) which monthly temperatures influence flowering and seed dispersal times; (2) species’ phenological sensitivity to temperature; and (3) whether flowering or seed dispersal times have advanced over the past 120 years. We tested this at different spatial scales and compared the sensitivity in different regions of Nunavut. Broadly speaking, this research serves as a proof of concept to assess whether phenology–climate change studies using historic data can be conducted at large spatial scales. Flowering times and seed dispersal time were most strongly correlated with June and July temperatures, respectively. Seed dispersal times have advanced at double the rate of flowering times over the past 120 years, reflecting greater late‐summer temperature rises in Nunavut. There is great diversity in the flowering time sensitivity to temperature of Arctic plant species, suggesting climate change implications for Arctic ecological communities, including altered community composition, competition, and pollinator interactions. Intraspecific temperature sensitivity and warming trends varied markedly across Nunavut and could result in greater changes in some parts of Nunavut than in others.  相似文献   

6.
本文报道了梵净山的大型真菌365种,分属于124属、41科。其中食用菌105种,药用菌87种,毒菌33种,木腐菌131种及菌根菌114种。梵净山的大型真菌分属于下列林型和植被型:阔叶林型;针阔混交林型;针叶林型;灌丛型和荒地型。营养方式主要分为寄生、腐生和共生三大类群。  相似文献   

7.
This study presents a quantitative partitioning of the total variance in the patterns of occurrence of 231 vascular plant taxa in 362 1 × 1 km grids in the Kevo Nature Reserve into four independent components: purely spatial variation, spatially structured environmental variation, non-spatial environmental variation, and unexplained variation. This partitioning is done with (partial) constrained ordinations (canonical correspondence analysis) and associated Monte Carlo permutation tests. The numerical results suggest that most of the biological variance captured by the external explanatory variables is related to 'local' meso-scale environmental factors, as 12.6% of the variation in the species data is explained solely by the environmental variables. Part of the variance (6%) represents a spatially covarying environmental component, but only a very small part, ca 2%, is related to purely spatial variation. The amount of unexplained variation is very high (>75%). The results are compared and discussed in relation to the relative amounts of these four variance components at broader- and finer-scales and to the concepts of domains and transition zones of scales in biological patterning.  相似文献   

8.
Yuri B. Okolodkov   《Harmful algae》2005,4(2):351-369
The global distributional patterns are presented for 14 toxic and potentially toxic dinoflagellate species (PSP, DSP, yessotoxin, azaspiracid and their analogues, ichthyotoxic and haemolytic compound producers) recorded from the Eurasian Arctic and which have caused harmful blooms elsewhere. The distributional patterns are based on materials collected during 28 expeditions to the Eurasian Arctic during the period from 1976 to 1999 (1810 samples from 539 stations) and about 500 literary sources. All Russian literature on the occurrences of dinoflagellates in the Eurasian Arctic was analyzed and relevant references are given.  相似文献   

9.
大型真菌是菌物中形成大型子实体的一类真菌,该类群中食药用资源极为丰富,许多种类具有显著的抗氧化活性。本文综述了国内外有关大型真菌具抗氧化活性的小分子次生代谢产物的化学结构及其活性的研究概况,以期对大型真菌的活性筛选、化学分析和开发利用提供借鉴。  相似文献   

10.
Plant phenological data from northern Finland, compiled from several sources, were examined as potential biometeorological indicators of climate change since the 18th century. A common feature of individual series was their sporadic nature. In addition to waning enthusiasm, wartime hardships and crop failures had caused gaps in recording observations during the 18th and 19th centuries. The present study’s challenge was to combine separate records, as retrieved from several historical archives and personal diaries, into a single continuous series. To avoid possible biases due to the variability of data availability each year, each phenomenon-specific mean series was transformed into normalized site-specific index series. These series were compared to each other and to a regional instrumental temperature series (years 1802–2011). The inter-phenomena correlations were high. Moreover, a strong biometeorological response of the phenological series, most especially to monthly mean temperature in May, and seasonally to the April through June temperatures, was identified. This response focused on slightly later spring months compared to the responses in an earlier study conducted for southern Finland. The findings encouraged us to compute a total phenological index series as an average of all available phenomenon-specific index series for northern Finland. The earliest phenological springs were found as a cluster in the recent end of the record, whereas the anomalously-late phenological spring could be found through the centuries. This finding could indicate that potential future warming could result in an earlier onset of phenological springs (i.e. as experienced by the plants), with a remaining possibility of late phenological springs. To conclude, it was shown that the indices are reliable biometeorological indicators of the April through June temperature variations and thus of the climate variability in the region.  相似文献   

11.
Baeospora occidentalis is described as a new species associated with melting snow in montane coniferous forests of the western USA. The species is spring-fruiting and is characterized by a long tapering pseudorhiza covered with white basal rhizomorphs which extends deeply into the needle litter or woody debris. It possesses a multiallelic, tetrapolar mating system. Monokaryotic mycelia produce arthroconidia.  相似文献   

12.
The 2 4thvolumeofJOURNALOFJILINAGRICULTURALUNIVERSITYwaspublishedinFebruary 2 0 0 2asmemorialissueofthelateProf.ZHOUZong huangatJilinAgriculturalUniversity .Inthisissueatotalof34myco logicalandphytopathologicalpaperswasreported ,aswellasadetailedintroductiontothescientificcareerandachievementsofProf.ZHOU .ThetopicsandtitlesofthepapersherewellrepresentrecenttrendsandprogressinthesefieldsofstudyinChina .MycologistsinAsiahavebeenconcernedwithmycologicalinformationfromChina .…  相似文献   

13.
广西种子植物新资料   总被引:2,自引:1,他引:1  
林春蕊  邹蓉  刘演 《广西植物》2009,29(3):309-310
报道了广西种子植物分布新记录3种:剪红纱花、头花水玉簪、大柱莓草,其中霉草科和喜荫草属分别为广西新记录科和新记录属;以及原来被认为在广西已经灭绝的广西重点保护植物胡豆莲也被重新发现。  相似文献   

14.
安徽清凉峰自然保护区大型真菌的生态分布   总被引:4,自引:2,他引:4  
柯丽霞  杨超 《应用生态学报》2003,14(10):1739-1742
清凉峰北坡的大型真菌十分丰富,经初步调查,发现清凉峰北坡共有大型真菌2纲10目38科72属160种,它们广泛分布于常绿阔叶林、马尾松林、常绿-落叶混交林、落叶阔叶林和黄山松林等林带中。按经济价值分有食用菌72种,药用菌55种,毒菌19种;依生态习性分有木生菌68种,土生菌84种,菌根真菌21种。本文论述了该地区大型真菌自然发生的常见种类和分布,并对该区大型真菌资源进行了评价,大型真菌在各林带下的分布有一定规律性,种群的组成和分布与植被类型、林中小生境、土壤类型、海拔高度等相关。该区有多种具有经济价值的大型真菌,是主要的自然资源之一,它们在食用、药用、营林等方面有着较大的利用潜力。  相似文献   

15.
Soil factors influencing ectomycorrhizal (ECM) sporome distribution in neotropical forests dominated by Pinus montezumae were examined at Sierra Chichinautzin, Mexico. Study sites were located on three volcanoes of different ages and ECM sporomes were collected during three consecutive years. Inocybe and Laccaria species were preferentially found at the youngest site, while Tricholoma and Russula species showed a more abundant distribution at the oldest site. Total sporome richness was negatively correlated with carbon (C) and nitrogen (N) contents in the soil organic horizon. Canonical correspondence analysis (CCA) was used to investigate the relationships between sporome species and soil variables. The CCA biplot showed that Amanita rubescens, I. fastigiata, and I. geophylla had a strong positive relationship with soil C and N contents, whereas Inocybe sp.4 was negatively related to these variables. This indicates an intra-generic variability in fungal responses to soil factors. The measured soil nutrients influenced species composition patterns, and the differences in sporome distribution evidenced a large degree of community specialization along the soil quality gradient. Together, these data contribute to a better understanding of the ecology of macrofungi in neotropical forests.  相似文献   

16.
Thirty years have passed since Carl Woese proposed three primary domains of life based on the phylogenetic analysis of ribosomal RNA (rRNA) genes. Adopted by researchers worldwide, rRNA has become the “gold-standard” for molecular taxonomy, biodiversity analysis and the identification of microorganisms. The more than 700,000 rRNA sequences in public databases constitute an unprecedented hallmark of the richness of microbial biodiversity on earth. The International Workshop on Ribosomal RNA Technology convened on April 7–9, 2008 in Bremen, Germany (http://www.arb-silva.de/rrna-workshop) to summarize the current status of the field and strategize on the best ways of proceeding on both biological and technological fronts. In five sessions, 26 leading international speakers and ∼120 participants representing diverse disciplines discussed new technological approaches to address three basic ecological questions: “Who is out there?” “How many are there?” and “What are they doing?”.  相似文献   

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贵州蕨类植物新记录   总被引:1,自引:0,他引:1  
代朝霞  苟光前 《植物研究》2006,26(4):387-388
报道了贵州省新记录的4种蕨类植物,分属3科,4属,它们是上毛凤丫蕨(Coniogramme suprapilosa)、具腺凸轴蕨(Metathelypteris glangdulosa)、光滑方秆蕨(Glaphyropteridopsis glabrata)和混淆鳞毛蕨(Dryopteris commixta)。  相似文献   

19.
This paper describes dispersed angiospermous pollen grains from the Maastrichtian of Sakhalin, Russia, with scanning electron microscopy. These pollen grains includeClavatipollenites, Tricolpites, andBetulaepollenites. Exine sculpture of the pollen grains are shown in detail. The palynomorphs imply a wide range of angiosperm diversity during Maastrichtian time at the mid- or high-latitudes in the eastern Eurasia.  相似文献   

20.
报道广西蕨类植物分布新记录1属7种1变型,即粉叶蕨属、锡金石杉、四川石杉、笔直石松、布朗卷柏、粤铁线蕨、粉叶蕨、大叶贯众、中华水龙骨.该文列出了每个种的标本引证和地理分布.  相似文献   

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