scholarly journals Ecological ordination of the grass vegetation in Altai Krai

2020 ◽  
Vol 10 (5) ◽  
pp. 192-196
Author(s):  
N.V. Ovcharova ◽  
A.V. Matsyura

The article shows a variety of ordination methods used to analyze different types of vegetation and presents the results of the ordinal analysis of meadow (i.a. idle lands) and steppe phytocenoses that are widespread in Altai Krai. Ecological ordination is performed by means of the Detrended Correspondence Analysis (DCA) method. The ordination of grass communities is based on 616 complete geobotanical descriptions (330 - meadow, 286 - steppe). The article determines the position of community types on the gradients of humidification and soil richness-salinity for steppes and suggests the directions of the progressive successions of idle land communities in Altai Krai.

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10349
Author(s):  
Zhenguo Zhang ◽  
Mingming Wang ◽  
Jikai Liu ◽  
Xinwei Li

Identification of typical vegetation succession types and their important influencing factors is an important prerequisite to implement differential vegetation and soil management after land abandonment on the Loess Plateau, China. However, there is no reported study specifically on the identification of vegetation types and their important factors as well as the thresholds of the important factors for classification of the vegetation types, based on the medium- to long-term succession of natural vegetation after cropland abandonment. We collected vegetation and soil data on the natural vegetation with the longest 60-year-old forest communities that developed after cropland abandonment and analyzed the data using two-way indicator species analysis, detrended correspondence analysis, direct canonical correspondence analysis and classification tree model. The vegetation communities were classified into five distinct vegetation types, including Artemisia scoparia, Lespedeza davurica and Stipa bungeana, Artemisia giraldii pamp, Sophora viciifolia, Quercus liaotungensis and Biota orientalis. The years after cropland abandonment and soil C/N were further identified as important factors determining the types of vegetation. Likewise, it was observed that most of the investigated soil nutrient variables and soil texture-related variables improved with the vegetation succession while soil water in the surface layers showed a decreasing trend. These findings may provide an ecological basis for site-specific management of vegetation types after cropland abandonment in the medium-long term on the Loess Plateau. Our results encourage further exploration of vegetation succession and their important factors based on longer periods of vegetation succession after cropland abandonment under more soil and climatic conditions on the mountainous areas as the Loess Plateau.


Koedoe ◽  
1997 ◽  
Vol 40 (2) ◽  
Author(s):  
L. Breebaart ◽  
M. Deutschlander

An analysis of the vegetation of Goedverwacht farm in the mixed bushveld of the Northern Province is presented. Releves were compiled in 33 stratified random sample plots. Eight distinct plant communities were identified by means ofBraun-Blanquet pro-cedures. Detrended correspondence analysis (DCA) was applied to the floristic data set using the computer programme DECORANA (Detrended Correspondence Analysis) to determine a probable environmental gradient and to facilitate in the identification of management units. The computer programme CANOCO (Canonical Correspondence Analysis) was used to apply canonical correspondence analysis (CCA) to the floristic data set. Two management units were determined by means of vegetation ordinations and soil data. A classification, description and ecological interpretation of the plant communities as well as a description of the management units are presented.


Koedoe ◽  
1989 ◽  
Vol 32 (1) ◽  
Author(s):  
N. Hanekom ◽  
A. Southwood ◽  
M. Ferguson

Sampling plots (5 m x 10 m in fynbos, 10 m x 10 m in forest) were analysed in the littoral, coastal escarpment, and north and south facing inland escarp- ment zones of 17 transect sites along the length of the Tsitsikamma Coastal National Park. Cover- abundance values were estimated for each species in the sampling plots. A detrended correspondence analysis (using CANOCO) and a two way indicator species analysis (TWINSPAN) were carried out on these data to determine the communities sampled. The vegetation of the park was classified into an Afromontane Forest, a Littoral Herbland and two Mesic Mountain Fynbos Communities. The distribution and extent of these communities were determined and their conservation discussed.


1989 ◽  
Vol 67 (10) ◽  
pp. 2967-2974 ◽  
Author(s):  
J. C. Earle ◽  
K. A. Kershaw

Plant zonations and selected environmental variables were studied in a subarctic coastal marsh at Ekwan Point, James Bay, Ont. Eight distinct community types were identified using two-way indicator species analysis classification (TWINSPAN). These were interpreted as a primary successional sequence. The eight communities were found to conform closely to the classical marsh zonations based on elevation and tidal influence: (1) lower salt marsh, (2) middle salt marsh, (3) upper salt marsh, (4) saline meadow, (5) freshwater meadow, and (6) freshwater fen. Environmental data collected along the vegetation transects indicated that changes in elevation and soil-water salinity probably influence species distributions. A species ordination using detrended correspondence analysis (DECORANA) revealed several trends in plant distribution patterns. Consideration of the environmental affinities of species separated along three ordination axes suggested that salinity and elevation, water content, and soil texture were probably important factors influencing successional processes in the marsh during at least the last century. An inverse salinity gradient, which has been reported at many sites along the west coast of Hudson and James bays, was not found at Ekwan Point.


Author(s):  
Luis M. Caillaux ◽  
Wolfgang B. Stotz

An evaluation was carried out on the distribution and abundance of the rock shrimp Rhynchocinetes typus in the inshore subtidal zone on the north-central coast of Chile. A number of different benthic community types occur in the region which have different degrees of spatial complexity provided by the primary substratum and by the biotic communities colonizing the substratum. Shrimp abundance was estimated in five different community types including shallow and deep ‘barren grounds’, low encrusting communities, erect suspension feeding associations, and kelp beds of Lessonia trabeculata. The abundance of shrimp was determined on three different types of primary substratum (stones, boulders, rock mass) within each community. Rhynchocinetes typus occurred in all the communities studied, showing the highest abundance on the deep barren grounds and lowest abundance on the shallow barren grounds. The shrimp was found to prefer the stony areas, as these offered the greatest degree of refuge. The abundance of predators was not significantly different among the different communities. However, a decline of abundance of predators was apparent over the deep barren grounds.


1992 ◽  
Vol 6 ◽  
pp. 320-320
Author(s):  
Jiping Yao

The present day vegetation types on the earth are to a large extent controlled by climatic conditions that are mainly reflected in variations in moisture availability and temperature through the annual cycle. Therefore, fossil plants can be used as a tool to elucidate both spatial and temporal climatic changes. The global climates of the Jurassic can be interpreted with fossil floras because many parts of world have yielded abundant floral localities. Those records not only provide a strong basis for the qualitative depiction of vegetation patterns, but also provide quantitative data for the reconstruction of paleophytogeographic provinces and climatic changes. The computer program known as “Detrended Correspondence Analysis” written by Hill (1979) was used in this study. The floral data for this quantitative approach was assembled at the generic level mainly from the published literature. By definition, it is a method based on ordination scores, that is, the species ordination scores are averages of the sample ordination scores, and vice versa.The scatter diagrams of the first two axes of genera and sample sites derived by detrended correspondence analysis were obtained for the intervals of Early, Middle, and Late Jurassic. The gradient variations of both genera and sample sites are reflected by the scores along axis 1 and 2 because axis 1 and axis 2 maximize the correlation of species and sample sites according to this technique. In the ordination score diagrams, the genera in similar climatic environments and the sample sites in similar paleogeographic regions are relatively close to each other along axis1 and axis2.One of characteristics of the Jurassic vegetation is the taxonomic stability through the period compared with other periods of time. Therefore, the generic scores of axis1 for the Early and Middle, Middle and Late, and Early and Late Jurassic can be plotted against each other. The regression line can be used to assign the scores to the ordered genera. This is the technique used to complement the ordered genera from the gradient score diagrams and to eliminate the effect of some local genera. The genera adjacent to the regression line can be reliably used to reflect climatic gradients. The gradient changes were used to define biomes and to determine phytogeographic patterns on a global scale.The quantitative analysis clearly shows that the use of floral data can achieve fast and satisfactory results in paleoclimatic studies of the Jurassic. For example, the cool-wet temperate climate is reflected by a ginkgophyte dominated deciduous flora, such as Ginkgo, Czekanowskia, Phoenicopsis, and Baiera, whereas the subtropical warm and drier climate is represented by cycad dominated floras, such as Anomozamites, Nilssonia, Pterophylum, Ptilophyllwn, Ctenis, and Otozamites. The general conclusion of earlier workers that Jurassic floras were especially uniform through the earth is true in the relative sense only, and the ordination study allows for the subdivision of the rather shallow gradients that do exist.


Koedoe ◽  
1997 ◽  
Vol 40 (1) ◽  
Author(s):  
J. Du P. Bothma ◽  
N. Van Rooyen ◽  
E.A.N. Le Riche

The hunting tactics of male and female leopards in the southern Kalahari were analysed for prey-specific patterns. The field study was based on tracking leopard spoor in the sandy substrate of the Kalahari. Visual profiles for each type of prey were compiled for various facets of hunting. Data sets were analysed further, using Correspondence Analysis and Detrended Correspondence Analysis. The results indicate that multivariate analysis can be used to demonstrate prey-specific hunting tactics in Kalahari leopards. In using a scarce prey base, Kalahari leopards seem to be number maximisers as they are unselective of prey type, age or sex. The presence of prey-specific hunting tactics may indicate a move along a continuum towards some degree of energy maximisation.


1985 ◽  
Vol 15 (6) ◽  
pp. 1099-1108 ◽  
Author(s):  
T. J. Carleton ◽  
R. K. Jones ◽  
G. Pierpoint

Problems arise in the use of understory vegetation as an indicator of site condition in that impermanent factors such as microclimate, succession, and chance may play significant roles in determining local composition. Residual ordination analysis is a method which facilitates quantification of the sources of variation in understory vegetation over a landscape. Here it is applied to survey data, representing 250 stands upon which the forest ecosystem classification programme for the Clay Belt portion of northeastern Ontario is based, to test the premise that vegetation types will differentiate soil conditions for forestry purposes. Ordination of the data by detrended correspondence analysis yielded a bivariate scatterplot which, through visual appraisal, seemed readily interpretable in terms of site-related nutrient and moisture gradients. Formal exploration, using canonical redundancy analysis, yielded the following predictive model: understory vegetation (detrended correspondence analysis axes 1 and 2) = soils (67%) + canopy (8%) + succession (1%) + error (24%). Extraction of residual ordinations confirmed this general model and demonstrated that although canopy and successional influences are minor in the data, they are significant. Because the nonsite-related, predictable components account for only 9% of the variation at most, the premise of the existing forest ecosystem classification system is judged to be sound insofar as the data upon which it is based adequately describe the range of commercial stand conditions normally encountered. The results are discussed in relation to vegetation survey design and the performance of residual ordination analysis on a large data set is assessed.


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