共查询到20条相似文献,搜索用时 15 毫秒
1.
Abstract The vegetation communities of the karst-tectonic basins of the Majella massif alpine belt were studied using the phytosociological methods, and analysed from coenological, synchorological and syntaxonomical viewpoints. During the field-work, 115 relevés were performed using the phytosociological approach of Braun-Blanquet, and these relevés were further subjected to multivariate analyses. Eight clusters of relevés resulted from the numerical classification. The plant communities identified in the study area were ascribed to the following five associations, two sub-associations and one community type: Leontopodio – Seslerietum juncifoliae (ass. nova); Helianthemo – Festucetum italicae (ass. nova); Gnaphalio – Plantaginetum atratae; Taraxaco – Trifolietum thalii gnaphalietosum magellensis (subass. nova); Luzulo italicae – Nardetum, Carici – Salicetum retusae; Saxifrago – Papaveretum julici, Saxifrago – Papaveretum androsacetosum (subass. nova), Plantago atrata and Leontodon montanus community. The distribution of these communities within the karst basins was found to be related to variations in topographic and geomorphological parameters, such as altitude, slope, soil availability and stoniness. All the new associations proposed in this paper belong to the suballiance Leontopodio – Elynenion and to the alliance Seslerion apenninae, both of which are endemic to the central Apennines. In order to compare the plant community types identified within the Majella massif to similar associations found in the rest of the Apennine chain, synoptic tables were constructed. Finally, a comparative phytogeographical analysis of the alpine belt vegetation of the Apennines, Dinarides, southern Balkans and eastern Alps is presented. 相似文献
2.
Searching for a model for use in vegetation analysis 总被引:8,自引:0,他引:8
M. P. Austin 《Plant Ecology》1980,42(1-3):11-21
Summary Indirect gradient analysis methods require an explicit vegetation model which must be based on direct gradient analysis studies. Various vegetation models are reviewed. Field evidence for the models is discussed. Experimental studies of species response to environmental gradients are reviewed and discussed. Three types of gradient are recognized as important for development of models: indirect environmental gradients where the environmental factor has no direct physiological influence on plant growth e.g. elevation; direct environmental gradients where the factor has a direct physiological effect on growth but is not an essential resource, e.g. pH; resource gradients where the factor is an essential resource for plant growth. The behaviour of the ecological carrying capacity and the role of competition along such gradients are shown to be important for developing vegetation models. 相似文献
3.
The Middle Miocene Marnoso-arenacea Formation at Deruta in the northern Apennines of Italy rests unconformably on an orogenic wedge adjacent to the Adriatic foredeep. Based on a detailed facies analysis, the succession reveals two genetically related depositional systems: a distal delta-fed sand-rich system and a more proximal fan-delta slope system. Petrographic data confirm the genetic relationship between the two depositional systems, with the fan-delta slope feeding the basinward sand-rich system. The Deruta depositional setting shows a multi-step sedimentary evolution controlled by tectonically induced relative sea-level changes. The first stage, corresponding to a sea-level rise, promoted deposition in a wedge-top basin of pebbly sand and sand lobes (delta-fed). The second stage, characterized by intense tectonic activity (uplift) and sea-level fall, promoted accumulation of a prograding fan-delta slope replacing the sand-rich lobes. This phase was dominated by mass failures and methanogenic cold seepages. During these two stages, the wedge-top basin was isolated from the adjacent foredeep. Only during the third stage was a connection established, with the development of a deep-sea fan in the foredeep, fed by a deltaic depositional system. 相似文献
4.
Summary In vegetation research selection of a technique for the analysis of phosphate in soil frequently presents problems with respect to selection criteria. In plant communities of hayfields in Drenthe (The Netherlands) such a criterium has been found by means of drawing axes with different ordination techniques (9 techniques, 43 axes). Each numerical approach obtained one or two axes, which were evidently related to variation in phosphate. Five different extraction techniques were used (Ammonium lactate, EDTA, KF, NaHCO3 and water). The outcome of these analyses could be classified in two groups: 1. P-KF and P-W (correlated with the ground water level) and 2. P-AL, P-EDTA and P-NaHCO3 (correlated with pH). The first group showed clearer relations with the relevant ordination axes. Phosphate indicator values according to Kruijne (P-citric acid) were related to the first group only. P-KF had higher correlations with the ordination axes. 相似文献
5.
Shrubland vegetation and environmental data in western Shewa, Ethiopia have been analysed. Vegetation data include cover-abundance values of vascular plant species; environmental data comprise physical and chemical properties of the soil, altitude, slope, grazing and browsing pressure. The vegetation data were subj ected to hierarchical and non-hierarchical classification and ordination with correspondence analysis. The classification resulted in seven different vegetation types, ranging from grassland with scattered shrubs to degenerated forest. Ordination of the data and biplot analysis showed that the vegetation is influenced by anthropogenic factors and altitudinal variation. Sand content is related to a low level of anthropogenic influence whereas silt content is related to a high level. This is explained by historical events rather than by the present situation. Total nitrogen, organic carbon, altitude and slope are positively correlated and these variables are negatively related to anthropogenic influences. The shrubland vegetation may have expanded from lower altitudes and drier sites as forests gradually disappeared. The recovery of an economically more rewarding vegetation type may be achieved through pro viding alternative sources of fuel and construction and through prohibiting cultivation and grazing in the shrublands on the hillsides. Regeneration can be accelerated by actively introducing seedlings of tree species that do not need a heavy canopy cover for establishment and growth. 相似文献
6.
Modern pollen representation of source vegetation in the Qaidam Basin and surrounding mountains, north-eastern Tibetan Plateau 总被引:3,自引:0,他引:3
We use a data set of 35 surface pollen samples from lake sediments, moss polsters and top soils on the north-eastern Tibetan
Plateau to explore the relationship between modern pollen assemblages and contemporary vegetation patterns. The surface pollen
transect spanned four vegetation zones––alpine meadow, steppe, steppe desert and desert––under different climatic/elevational
conditions. Relative representation (R
rel) values and Principal Components Analysis (PCA) were used to determine the relationships between modern pollen and vegetation
and regional climate gradients. The results show that the main vegetation zones along the regional and elevational transects
can be distinguished by their modern pollen spectra. Relative to Poaceae, a high representation of Artemisia, Nitraria and Chenopodiaceae was found, while Cyperaceae and Gentiana showed values in the middle range, and Ranunculaceae, Asteraceae, Ephedra and Fabaceae had low relative representation values. PCA results indicate a high correlation between the biogeoclimatic zones
and annual precipitation and annual temperature and July temperature. The Artemisia/Chenopodiaceae ratio and the Artemisia/Cyperaceae ratio are useful tools for qualitative and semi-quantitative palaeoenvironmental reconstruction on the north-eastern
Tibetan Plateau. Surface lake sediments are found to have different palynomorph spectra from moss cushion and soil samples,
reflecting the larger pollen source area in the contemporary vegetation for lakes. 相似文献
7.
Troop size,home range area and seasonal range use of the Japanese macaque in the Northern Japan Alps
Home range area and habitat use of the wild Japanese macaque (Macaca fuscata) were investigated between elevations of 600m and 3000m in the Northern Japan Alps, in areas where there is great variation in vegetation type. A total of 22 troops were located either visually or by radiotracking from December 1996 to February 2000. The average troop size was 48.4 individuals, the average ranging area (65% probability distribution calculated using the adaptive kernel method) was 3.7km2 and the average elevation of each troop varied from 740m to 1458m. Two troop types were distinguished according to their habitat use: (i) rural type groups frequently utilized cultivated land (n=12); and (ii) natural type groups never utilized cultivated land (n=10). Natural groups inhabited higher elevation areas and showed a greater dependency on deciduous broad-leaved forests during all seasons. In contrast, rural groups utilized the larch plantation more in spring, and the red pine forest in summer. Rural groups were observed on cultivated lands more often from summer to winter than in spring. The size of the rural groups was twice as large as that of the natural groups. Troop size and home range area showed significant correlation within each group type. The per capita home range area of rural groups was smaller than that of natural groups. These results suggest that per capita home range area is negatively correlated with habitat quality. 相似文献
8.
A three-dimensional compositional pattern in the epiphytic lichen vegetation in Tasmanian cool temperate rainforest is demonstrated using the robust ordination technique, hybrid multidimensional scaling (HMDS). The first two dimensions are correlated with the age of the host tree (and the concomitant change in bark texture) and wetness of the substrate. No measured environmental variable is related to the third dimension, which is tentatively attributed to a gradient in the constancy of the microclimate. Patterns of richness of lichen growth forms and the cover of bryophytes are correlated with the three putative environmental gradients. Possible successional trends between 12 community groups derived by numerical classification are described with respect to changes in substrate age, wetness and microclimatic constancy. Temporal variation of these factors due to tree growth, together with the slow establishment and long persistence of some lichen species, make succession in epiphytic communities very complex. This study demonstrates the value of HMDS in identifying compositional patterns and generating hypotheses about the causal ecological factors. The existence of the postulated microclimatic constancy gradient was not appreciated before the analysis and its discovery illustrates the risk of relying on constrained ordination methods, such as canonical correspondence analysis.Abbreviations HMDS
Hybrid multidimensional scaling
- NMDS
Non-metric multidimensional scaling 相似文献
9.
The use of climatic parameters and indices in vegetation distribution. A case study in the Spanish Sistema Central 总被引:1,自引:0,他引:1
Gavilán RG 《International journal of biometeorology》2005,50(2):111-120
In this study, over 100 phytoclimatic indices and other climatic parameters were calculated using the climatic data from 260 meteorological stations in a Mediterranean territory located in the centre of the Iberian Peninsula. The nature of these indices was very different; some of them expressed general climatic features (e.g. continentality), while others were formulated for different Mediterranean territories and included particular limits of those indices that expressed differences in vegetation distribution. We wanted to know whether all of these indices were able to explain changes in vegetation on a spatial scale, and whether their boundaries worked similarly to the original territory. As they were so numerous, we investigated whether any of them were redundant. To relate vegetation to climate parameters we preferred to use its hierarchical nature, in discrete units (characterized by one or more dominant or co-dominant species), although it is known to vary continuously. These units give clearer results in this kind of phytoclimatic study. We have therefore used the main communities that represent natural potential vegetation. Multivariate and estimative analyses were used as statistical methods. The classification showed different levels of correlation among climatic parameters, but all of them were over 0.5. One hundred and eleven parameters were grouped into five larger groups: temperature (T), annual pluviothermic indices (PTY), summer pluviothermic indices (SPT), winter potential evapotranspiration (WPET) and thermal continentality indices (K). The remaining parameters showed low correlations with these five groups; some of them revealed obvious spatial changes in vegetation, such as summer hydric parameters that were zero in most vegetation types but not in high mountain vegetation. Others showed no clear results. For example, the Kerner index, an index of thermal continentality, showed lower values than expected for certain particular types of vegetation. Parameters relating to the water balance turned out to be very discriminative for separating vegetation types according to the season or the month when water begins to be scarce. Thus, water availability in soils is a limiting factor for the development of vegetation in spring or autumn as well as in summer. As expected, precipitation and temperature discriminated the altitudinal levels of vegetation. Finally, these index limits only worked in the territories where they were formulated, or in nearby areas. 相似文献
10.
11.
Susanne Jahns 《Vegetation History and Archaeobotany》2006,15(1):57-63
A pollen diagram from the Ahlequellmoor in the Solling area shows the history of vegetation and settlement over the last 7,800
years. In the early Atlantic period mixed deciduous forest with mainly Tilia together with Ulmus and Quercus
grew in the area. In the late Atlantic period Quercus became most abundant. Fagus spread in the Sub-boreal period at about 2700 B.C. Since ca. 900 B.C. the Solling was covered by beech forests with some
oak. In prehistoric times woodland grazing is indicated. Only in Medieval times are two settlements in the vicinity of the
Ahlequellmoor reflected in the pollen diagram. The earlier one is dated to about A.D. 750–1020, and may be connected with
the former Monastery of Hethis, which is thought to have existed close to the fen from A.D. 815 to 822. The second Medieval
settlement dates to the 11th–12th century. The large-scale woodland destruction of late Medieval and modern times is not clearly
visible. The silvicultural measures of the last 200 years are reflected by increasing values of spruce and grassland taxa. 相似文献
12.
Altitudinal changes in composition and structure of mountain-temperate vegetation: a case study from the Western Carpathians 总被引:3,自引:0,他引:3
Changes in composition and structure of plant communities in relation tothe soil and snow cover variation were analyzed along an altitudinal transect(1150–1750 m) from the mountain-temperate forests to a woodyshrub community and alpine meadows on Mt Velký Gápel', Slovakia.The soils below the treeline (1510 m) had a more developedorganic layer above the mineral substratum. Generally, soil depth decreased asthe altitude increased, although the maximum values were recognized at a middlealtitude in a beech stand. Snow was redistributed by westerly winds from theridgeline down to the upper forest margin. Mean snow depth decreased withaltitude up to almost snow-free sites around the summit. In the 48 plots at 16sites we recorded 118 taxa including 6 tree, 7 shrub, 18 grass, 42 herb, 5fern,25 moss and 15 lichen species. The species diversity showed no distinctrelationship to altitude but declined with canopy consolidation. The TWINSPANfloristic classification distinguished five groups of community typescharacterised by different dominants, and a further three clusters of samplesfrom transition zones. Horizontal compositional heterogeneity increased inareaswhere trees were aggregated and tree basal area was smaller. Vegetationcomposition became more patchy at open-canopy Acerpseudoplatanus–Abies alba mixed forest at 1150 m,in Picea abies forest limit 1470 m, andin Pinus mugo krummholz at 1590 m. Speciesturnover of the entire transect was 6.1 half-changes as estimated by DCA.Despite this heterogeneity, none of the 15 elevational bands had significantaggregation of species' limits. Vegetation varied continuously, with individualspecies overlapping in transition zones delimited by dominant taxa. Thecoincident aggregation of up-slope and down-slope boundaries was found at abelt1430–1510 m. This discrete ecotone corresponds to a shiftfrom the closed coniferous forest to P. mugo krummholz.Thesecond inherent up-slope boundary aggregation indicated the P.mugo krummholz – alpine meadow vegetation transition at1700 m. Spatial analysis (K-function) of eight forest plots(0.12 ha each) showed that at lower elevation, adult trees of thebroad-leaf forest were closer to a random arrangement while at higherelevation,trees of evergreen coniferous stands became aggregated toward the forest limitwith the highest intensity from 2 to 4 m. Altitudinal gradient andrelated factors explained 35% of the variance in vegetation data.Canonical correspondence analysis also showed that main vegetation changesabovethe treeline area were associated with the topographic pattern of pine shrubsand snow cover. 相似文献
13.
A characteristic microfacies of the Late Jurassic to Early Cretaceous allodapic Barmstein Limestone of the Northern Calcareous
Alps are clasts of wackestones with numerous fragments of calcareous algae (“algal debris-facies”). According to dasycladale
palaeocoenoses, several subtypes comprising different associations can be distinguished. One association is characterized
by the debris of an unknown large dasycladalean alga reported as dasycladalean alga indet. sp. 1 from different localities
in the Northern Calcareous Alps, typically forming a monospecific assemblage. Another microfacies type contains star-like
calcitic bodies tentatively referred to the morphospecies Coptocampylodon pantici Ljubović-Obradović and Radoičić, originally described as being from the Turonian of NW-Serbia. Other Coptocampylodon-like bodies represent the calcified tufts of the laterals of Selliporella neocomiensis (Radoičić). The occurrence of Coptocampylodon pantici-like microfossils in the Late Tithonian to Early Berriasian, shows that obviously different species of dasycladaleans display
identical to similar shaped tufts of laterals in transverse sections when becoming fragmented. Coptocampylodon pantici Ljubović-Obradović and Radoičić was observed only from different occurrences of Barmstein Limestone, but not from the autochthonous
platform carbonates of the Plassen carbonate platform. The Coptocampylodon algal debris-facies is also reported from the Late Jurassic of Albania, Mirdita zone. Occurrences of different types of algal
debris-facies in components of mass-flow deposits can be used as a tool to reconstruct eroded carbonate platforms and tectonics,
as demonstrated in the Northern Calcareous Alps and the Albanides. Finally, the general occurrences of algal debris-facies
in both settings—intra-Tethyan mostly isolated platforms (Alps, Albanides) vs. extended epeiric platforms (Middle East)—are
compared and discussed. 相似文献
14.
This paper presents a quantitative account of vegetation–soil environmental factor relationships in the Wangsuk stream (WS)
and the Gwarim reservoir (GR) in Korea. Vegetation and the following soil variables were investigated in May, August and October
2004: pH, conductivity, water content, organic matter, total nitrogen content, NH4–N content, PO4–P content, total Ca, Mg, K, and Na content, extractable Ca, Mg, K and Na content, soil texture, distance from the channel,
and elevation above water level. Species richness, diversity and ratio of hydrophyte occupation in WS were different from
those in GR. Species richness was higher in WS, whereas the ratio of hydrophyte occupation was higher in GR. There were large
temporal and spatial variations in plant distribution in the riparian and aquatic zones of WS but only slight variations in
those of GR. These differences might have arisen from differences in flooding regime, distance from the stream channel related
to elevation above water level, and soil properties such as soil texture and available nutrients. The median values of organic
matter, total nitrogen, NH4–N, PO4–P and extractable Ca, Mg, K and Na contents in the soil were higher in GR than in WS. Sandy loam and loamy sand were common
soil types in WS and clay loam and sandy clay loam in GR. Ten vegetation groups in WS and six in GR were identified using
TWINSPAN. DCCA indicated that the distance from the stream channel was most strongly related to plant distribution and this
reflected the spatial distribution of plant species in WS. In both WS and GR, NH4–N content in soil and soil texture were important factors for the distribution of species in May, August and October. Spatial
and temporal heterogeneity of soil variables were related to species distribution. 相似文献
15.
A radiocarbon-dated pollen profile provides the first evidence for the vegetation history of the north-west Burren, a karstic region in Co. Clare, western Ireland. The profile, which spans the period ca. 3200-0 B.P., shows that Corylus was the main woody species and that, apart from the later eighteenth and nineteenth centuries, when woody species were almost totally cleared, it constituted a more important element in the landscape than at present. The data indicate that small populations of Quercus, Fraxinus, Betula, Alnus and possibly Ulmus were also present until at least the mid seventeenth century. Exceptionally high values of Plantago lanceolata (mostly in excess of 20% total terrestrial pollen) suggest intensive pastoral farming over most of the period. Between A.D. 200–580, a lull in activity is recorded during which woody species and, in particular, hazel scrub regenerated. The separation of pollen of cereal origin from large cereal-type pollen produced by non-cultivated grasses proved particularly problematic. Reliance has therefore been placed on the weed pollen flora as a guide to arable activity. This flora indicates that arable farming was of some importance in the Burren from A.D. 1000 onwards. The implications of the various findings for the longer term history of the rarer elements of the Burren flora and the relationship between the pollen record and the archaeological and historical evidence for settlement and land use are discussed. 相似文献
16.
The aim of this work was to relate depth profiles of prokaryotic community composition with geochemical processes in the deep subseafloor biosphere at two shallow-water sites on the Peru Margin in the Pacific Ocean (ODP Leg 201, sites 1228 and 1229). Principal component analysis of denaturing gradient gel electrophoresis banding patterns of deep-sediment Bacteria, Archaea, Euryarchaeota and the novel candidate division JS1, followed by multiple regression, showed strong relationships with prokaryotic activity and geochemistry (R(2)=55-100%). Further correlation analysis, at one site, between the principal components from the community composition profiles for Bacteria and 12 other variables quantitatively confirmed their relationship with activity and geochemistry, which had previously only been implied. Comparison with previously published cell counts enumerated by fluorescent in situ hybridization with rRNA-targeted probes confirmed that these denaturing gradient gel electrophoresis profiles described an active prokaryotic community. 相似文献
17.
L. Mucino 《Plant Ecology》1982,48(3):267-275
The ruderal communities of the orders Sisymbrietalia and Onopordetalia from the western part of Slovakia have been subjected to numerical classification and ordination. The ordination techniques proved to be a useful tool in the elucidation of the cluster pattern as well as in the detection of the main environmental variation underlying the floristic variation within the data. Results obtained with numerical techniques and traditional syntaxonomical classification have been compared. The similarity between these results is low at the level of the orders. This incompatability is explained by the differences in the weighting of the species in the course of the classification process and by the addition of non-floristical criteria that often occurs in syntaxonomical classification according to Braun-Blanquet. The highest value has been observed at the 3-clusters level (both orders and the Malvion neglectae). High similarity among the results of the numerical techniques have been observed, particularly in the group of space-dilating clusterings (Ward's method, Complete linkage clustering and MeQuitty's similarity analysis). Average linkage clustering produces the most diverse result. The Malvion neglectae appeared as a separate group in all numerical techniques adopted. This suggests the upranking of its syntaxonomical position. The Bromo-Hordeion murini turned out to be a very heterotoneous syntaxon. 相似文献
18.
根据颗粒体病毒颗粒体蛋白(Granulin)基因在其起始密码子上游的12个碱基高度保守序列(TATAAGGAATTT)以及大菜粉蝶颗粒体病毒(PbGV)的颗粒体蛋白基因的序列[1]设计引物,PCR扩增得到850bp左右大小的片段,核苷酸序列测定结果表明该病毒的granulin基因全长为855bp,起始密码位于第38~40位碱基,终止密码位于779~781位碱基,编码框序列全长为744;推测该基因编码一段由247个氨基酸组成的多肽,分子质量约为2.9178×104道尔顿。与其它颗粒体病毒颗粒体蛋白基因进行同源性比较,核苷酸同源性都在70%以上,氨基酸同源性都在75%以上,最高的为大菜粉蝶颗粒体病毒(PbGV),核苷酸同源性为97%,氨基酸同源性为98%。构建了重组表达载体pet-28a-Gran,IPTG诱导后经SDS-PAGE检测,表明获得了颗粒体蛋白基因在大肠杆菌BL21中的特异表达。 相似文献
19.
The representation of root processes in models addressing the responses of
vegetation to global change 总被引:5,自引:0,他引:5
The representation of root activity in models is here confined to considerations of applications assessing the impacts of changes in climate or atmospheric [CO2 ]. Approaches to modelling roots can be classified into four major types: models in which roots are not considered, models in which there is an interplay between only selected above-ground and below-ground processes, models in which growth allocation to all parts of the plants depends on the availability and matching of the capture of external resources, and models with explicit treatments of root growth, architecture and resource capture. All models seem effective in describing the major root activities of water and nutrient uptake, because these processes are highly correlated, particularly at large scales and with slow or equilibrium dynamics. Allocation models can be effective in providing a deeper, perhaps contrary, understanding of the dynamic underpinning to observations made only above ground. The complex and explicit treatment of roots can be achieved only in small-scale highly studied systems because of the requirements for many initialized variables to run the models. 相似文献
20.
For soil and water erosion control in slope farmland, field experiments consisting of corn?+?no straw application?+?longitudinal ridge (CNL-CK), corn?+?stubble standing?+?cross ridge (CSSC), corn?+?straw application?+?cross ridge (CSC), soybean?+?straw application?+?cross ridge (SSC) and alfalfa?+?straw application?+?cross ridge (ASC) were conducted. Compared with the traditional CNL cropping pattern, soil loss in CSSC, CSC, SSC, and ASC was decreased 43.6%, 48.6%,58.2% and 62.1%, respectively, soil nitrogen loss load was decreased 53.8%, 50.8%, 62.1% and 66.2%, respectively, and soil phosphorus loss load was decreased 50.7%, 50.7%, 60.0%, and 66.7%, respectively. Runoff volume was decreased 42.4%, 52.3%, 54.6% and 61.0%, runoff nitrogen loss load was decreased 52.8%, 56.8%, 46.1% and 50.2%, respectively, and runoff phosphorus loss load was decreased 46.9%, 78.2%, 67.2%, and 62.7%, respectively. Soil and water erosion control of soybean and alfalfa were better than that of corn. Soil loss was decreased 19.2% and 26.7%, soil nitrogen loss load was decreased 22.9% and 31.3% respectively, soil phosphorus loss load was decreased 18.9% and 32.4% respectively, runoff volume was decreased 4.8% and 18.4% respectively, runoff nitrogen loss load was decreased ?24.9% and ?15.3% respectively, and runoff phosphorus loss load was decreased ?50.4% and ?71.2% respectively. Though runoff volume of SSC and ASC were lower than CSC, the concentration of nitrogen and phosphorus in SSC and ASC runoff liquid were higher than CSC, so the runoff nitrogen and phosphorus of SSC and ASC were increased. The runoff nitrogen and phosphorus loss load could be negligible because the soil nitrogen and phosphorus loss load were large. The concentration of nitrogen and phosphorus of all treatment runoff liquid was less than the environmental quality standards for class III surface water, so the runoff from slope farmland did not influence the water quality of the Songhua River. 相似文献