Studies on structure in plant communities. VI. The significance of pattern evaluation in some Australian dry-land vegetation types

1969 ◽  
Vol 17 (2) ◽  
pp. 315 ◽  
Author(s):  
DJ Anderson ◽  
SWL Jacobs ◽  
AR Malik

The analysis of density data from a variety of Australian dry-land vegetation types provides evidence of widespread randomness when the component distributions are compared with a Poissonian model. While such randomness may be reflecting traditionally held beliefs concerning structure in colonizing and "relict" populations, randomness may develop as a result of a differential elimination of individuals between high and low density phases in an originally patterned population. It is suggested that structure in vegetation cannot be estimated reliably by simple observation alone, and this statement is evidenced by the ubiquity of random (and to a lesser extent contagious) distributions which are found in Australian dry-land communities, in contradistinction to the widely held view that such distributions are necessarily essentially regular in their character.

Koedoe ◽  
1995 ◽  
Vol 38 (1) ◽  
Author(s):  
G.J. Bredenkamp ◽  
H. Bezuidenhout

A procedure for the effective classification of large phytosociological data sets, and the combination of many data sets from various parts of the South African grasslands is demonstrated. The procedure suggests a region by region or project by project treatment of the data. The analyses are performed step by step to effectively bring together all releves of similar or related plant communities. The first step involves a separate numerical classification of each subset (region), and subsequent refinement by Braun- Blanquet procedures. The resulting plant communities are summarised in a single synoptic table, by calculating a synoptic value for each species in each community. In the second step all communities in the synoptic table are classified by numerical analysis, to bring related communities from different regions or studies together in a single cluster. After refinement of these clusters by Braun-Blanquet procedures, broad vegetation types are identified. As a third step phytosociological tables are compiled for each iden- tified broad vegetation type, and a comprehensive abstract hierarchy constructed.


Author(s):  
O.A. Anenkhonov ◽  
◽  
D.V. Sandanov ◽  
A.A. Zverev ◽  
A.Yu. Korolyuk ◽  
...  

The long-term soil temperature monitoring in the area of more than 550 km in length within the region of Transbaikalia has been carried out. Sites for the monitoring were represented by the forest-steppe vegetation of different ecotopological and ecogeographical patterns. It was revealed that the dynamics of temperature regimens are highly synchronized reflecting the macroclimatic unity of the region. The sufficiently higher heat supply on the southerly exposed slopes comparing to northerly exposed ones was demonstrated. The distinctness between soil temperature regimens in different sites was revealed and attributed to the size of forested patches within the forest-steppe landscape, as well as discrepancies between eco-geographical features of sites along the sublatitudinal gradient. Differences between the vegetation types that occurred on the northern and southern slopes as well as between key sites scattered throughout the region were underlined. These differences are suggested to be connected with the spatial differentiation of the soil temperature. It was established that vegetation on the southern slopes is relatively more homogeneous being related to the single class Cleistogenetea squarrosae, while on the northern slopes plant communities related to three classes were developed, namely steppe class Cleistogenetea squarrosae, and two forest classes – Rhytidio-Laricetea and Vaccinio-Piceetea.


2020 ◽  
Vol 1 ◽  
pp. 53-75
Author(s):  
Dimitrios Zervas ◽  
Ioannis Tsiripidis ◽  
Erwin Bergmeier ◽  
Vasiliki Tsiaoussi

Aims: This study aims to contribute to the knowledge of European freshwater lake ecosystems with updated and new information on aquatic plant communities, by conducting national-scale phytosociological research of freshwater lake vegetation in Greece. Moreover, it investigates the relationship between aquatic plant communities and lake environmental parameters, including eutrophication levels and hydro-morphological conditions. Study area: Lakes in Greece, SE Europe. Methods: 5,690 phytosociological relevés of aquatic vegetation were sampled in 18 freshwater lake ecosystems during 2013–2016. The relevés were subjected to hierarchical cluster and indicator species analyses in order to identify associations and communities of aquatic vegetation, as well as to describe their syntaxonomy. Multiple regression analysis was applied to investigate the relationship between vegetation syntaxa and environmental parameters of lakes, i.e. physico-chemical parameters and water level fluctuation. Results: Ninety-nine plant taxa belonging to 30 different families were recorded. Forty-six vegetation types were identified and described by their ecological characteristics, diagnostic taxa and syntaxonomical status. Thirteen vegetation types, the largest number belonging to the vegetation class Charetea, are considered to be new records for Greece. The distribution of the vegetation types recorded in the 18 freshwater lakes was found to depend on environmental parameters and levels of eutrophication. Conclusions: An updated aquatic vegetation inventory was produced for Greek lakes, and primary results showed that the presence/absence of aquatic plant communities and the community composition in freshwater lakes can be utilized to assess the pressure of eutrophication on lake ecosystems. Taxonomic reference: Euro+Med (2006–). Abbreviations: MNT = Mean number of taxa; WFD = Water Framework Directive.


2011 ◽  
Vol 8 (8) ◽  
pp. 2047-2061 ◽  
Author(s):  
D. B. Metcalfe ◽  
R. A. Fisher ◽  
D. A. Wardle

Abstract. Understanding the impacts of plant community characteristics on soil carbon dioxide efflux (R) is a key prerequisite for accurate prediction of the future carbon (C) balance of terrestrial ecosystems under climate change. However, developing a mechanistic understanding of the determinants of R is complicated by the presence of multiple different sources of respiratory C within soil – such as soil microbes, plant roots and their mycorrhizal symbionts – each with their distinct dynamics and drivers. In this review, we synthesize relevant information from a wide spectrum of sources to evaluate the current state of knowledge about plant community effects on R, examine how this information is incorporated into global climate models, and highlight priorities for future research. Despite often large variation amongst studies and methods, several general trends emerge. Mechanisms whereby plants affect R may be grouped into effects on belowground C allocation, aboveground litter properties and microclimate. Within vegetation types, the amount of C diverted belowground, and hence R, may be controlled mainly by the rate of photosynthetic C uptake, while amongst vegetation types this should be more dependent upon the specific C allocation strategies of the plant life form. We make the case that plant community composition, rather than diversity, is usually the dominant control on R in natural systems. Individual species impacts on R may be largest where the species accounts for most of the biomass in the ecosystem, has very distinct traits to the rest of the community and/or modulates the occurrence of major natural disturbances. We show that climate vegetation models incorporate a number of pathways whereby plants can affect R, but that simplifications regarding allocation schemes and drivers of litter decomposition may limit model accuracy. We also suggest that under a warmer future climate, many plant communities may shift towards dominance by fast growing plants which produce large quantities of nutrient rich litter. Where this community shift occurs, it could drive an increase in R beyond that expected from direct climate impacts on soil microbial activity alone. We identify key gaps in knowledge and recommend them as priorities for future work. These include the patterns of photosynthate partitioning amongst belowground components, ecosystem level effects of individual plant traits, and the importance of trophic interactions and species invasions or extinctions for ecosystem processes. A final, overarching challenge is how to link these observations and drivers across spatio-temporal scales to predict regional or global changes in R over long time periods. A more unified approach to understanding R, which integrates information about plant traits and community dynamics, will be essential for better understanding, simulating and predicting patterns of R across terrestrial ecosystems and its role within the earth-climate system.


2020 ◽  
Vol 57 (1) ◽  
pp. 29-54 ◽  
Author(s):  
Daniele Viciani ◽  
Marisa Vidali ◽  
Daniela Gigante ◽  
Rossano Bolpagni ◽  
Mariacristina Villani ◽  
...  

This study provides a first step toward the knowledge of the alien-dominated and co-dominated plant communities present in Italy. The first ever checklist of the alien phytocoenoses described or reported in literature for the Italian territory has been compiled, produced by data-mining in national and local thematic literature. The resulting vegetation-type draft-list has been checked in the light of the most recent syntaxonomic documentation and updated with regards to syntaxonomy and nomenclature, with special reference to the frame proposed in the Italian Vegetation Prodrome. The list includes 27 vascular and one bryophyte vegetation classes, hosting 194 low rank alien-dominated syntaxa. The different vegetation types detected for each syntaxonomic class and macro-vegetation group, defined by physiognomical and ecological attributes, are discussed.


Koedoe ◽  
1998 ◽  
Vol 41 (2) ◽  
Author(s):  
A.E. Cauldwell ◽  
U. Zieger ◽  
M.G. Bingham ◽  
G.J. Bredenkamp

A phytosociological analysis of the physical environment and the natural plant communities of Mtendere Game Ranch in the Chibombo District of the Central Province of Zambia is presented. A TWINSPAN classification and DECORANA ordination based upon 69 releves revealed three vegetation types, grassland, woodland and thicket, that are subdivided into the following plant communities: Dambo, Munga Woodland, Miombo Woodland, Termitaria and Deciduous Thicket. The natural vegetation of Mtendere Game Ranch is separated into fire management units on the basis of the vegetation types.


2021 ◽  
Vol 78 (1) ◽  
pp. 3-22
Author(s):  
M.M. Fedoronchuk ◽  
◽  
N.B. Klimovych ◽  

To assess the coenotic peculiarities of species of the genus Epilobium (Onagraceae), in particular their coenotic amplitudes in the syntaxa of vegetation of Ukraine, 986 relevés from literature sources were analyzed. The names of syntaxa are provided in accordance with the Prodromus of the vegetation of Ukraine. Species of the genus Epilobium are widely represented in many plant communities and participate in the formation of natural, semi-natural and ruderal coenoses, where they are often diagnostic or characteristic species of associations, alliances, orders and classes of vegetation, or only present in their floristic composition. Epilobium species are present in 28 classes, which is evidence of their broad coenotic amplitudes and representation in different vegetation types: wetland, grassland, halophytic, forest, shrubs, chasmophytic, alpine, and anthropogenic (synanthropic). The widest coenotic amplitudes were revealed in such species as: E. hirsutum, E. palustre, E. angustifolium, E. parviflorum, E. tetragonum, E. montanum, E. alsinifolium, and E. collinum. According to the range of coenotic amplitude, all species can be subdivided into three groups: hemistenotopic, which occur within one class (E. adenocaulon, E. dodonaei, E. lamyi, E. nutans), hemi-eurytopic (within two or three classes) – E. alpestre, E. roseum, and eurytopic (within more than three classes) – E. alsinifolium, E. angustifolium, E. collinum, E. hirsutum, E. montanum, E. palustre, E. parviflorum, E. tetragonum. As for participation of species in the coenosis, the vast majority of them are assectators, and only a small portion can be temporary edificators (in some groups, at certain successive stages of vegetation development: E. angustifolium). Plants of Epilobium species can reproduce rapidly, both vegetatively and by seeds, which promotes their active colonization of new habitats. However, they usually do not tolerate increased shading and coenotic competition with other plant species, so their strategy is mainly ruderal.


Forests ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 674
Author(s):  
Hansol Lee ◽  
Bong Soon Lim ◽  
Dong Uk Kim ◽  
A Reum Kim ◽  
Jae Won Seol ◽  
...  

This study was carried out to clarify the vegetation decline due to air pollutants emitted in the process of industrial activities and the passive restoration of the vegetation due to socioeconomic changes after economic growth. To achieve this goal, we investigated the spatial distribution of vegetation, differences in species composition and diversity among vegetation types different in damage degree, vegetation dynamics, the age structure and annual ring growth of two dominant plant species, and the landscape change that occurred in this area over the last 50 years. Plant communities tended to be spatially distributed in the order of grassland, shrubland (dominated by Styrax japonicus Siebold and Zucc. community), and forests (dominated by Pinus thunbergii Parl. and Pinus densiflora Siebold and Zucc. communities), with increasing distance from the pollution source. The result of stand ordination based on vegetation data reflected the trend of such a spatial distribution. Species richness evaluated based on the species rank dominance curve was the highest in shrubland and the lowest in grassland; species richness in forests was intermediate. The size class distribution of woody plant species in four plant communities composing three vegetation types showed the possibility of them being replaced by forest in the late successional stage. However, the density of successor trees was relatively low, whereas the density of shrubby plants, which are resilient to air pollution, was very high. The age class distribution of a dominant species forming shrubland and pine forest showed that most of them were recruited after industrialization in this area. The period when young individuals in both vegetation types were recruited corresponded to the period when the annual ring growth of the pine trees that survived air pollution was reduced. An analysis of the landscape change in this area indicated that coniferous forest and agricultural field decreased greatly, whereas industrial area, residential area, mixed forest, and broadleaved forest showed increasing trends since construction of the industrial complex. As a result, the decrease in coniferous forest is usually due to vegetation decline and partially to succession, as the pine trees dominating the forest are not only sensitive to air pollution but are also shade-intolerant. The increase in mixed and broadleaved forests reflects vegetation decline or succession. Vegetation decline progressed for about 30 years after the construction of the industrial complex; it has begun to be restored passively since then, although the change has been slow. These results are in line with the environmental Kuznets curve hypothesis that environmental degradation increases in the early stages of economic growth to a certain point, and, after a turning point, economic development leads to environmental improvements—thus, there is an inverted U-shaped relationship between economic growth and environmental degradation.


2017 ◽  
pp. 77-92 ◽  
Author(s):  
K. B. Popova ◽  
O. V. Cherednichenko ◽  
A. V. Razumovskaya

The Rybachiy and Sredniy peninsulas are situated at the 69th latitude and bounded by the Barents Sea. Their territories belong to the subarctic tundra. Coastal vegetation is the case of the azonal one, which is regularly disturbed by sea. The aim of the study is to find out the coastal plant communities diversity and investigate ecological and floristic features of the vegetation types. The classification, based on 99 original relevés using TWINSPAN algorithm and following analytical revision, was carried out with Braun-Blanquet approach. The plant communities were classified into 5 associations and one community type. These syntaxa belong to 4 alliances, 4 orders, and 3 classes (Cakiletea maritimae R. Tüxen et Preising in R. Tüxen 1950, Honckenyo peploidis–Leymetea arenarii R. Tüxen 1966, Juncetea maritimi Br.-Bl. in Br.-Bl., Roussine et Negre 1952). There is a special change in coastal vegetation while moving away from sea. Therefore, it is a case of local zonality. The halo-nitrophilous communities of ass. Atriplicetum lapponicae on sandy and shingle wash margins with seaweed debris are common for the low-level beaches. Further from sea they are changing by communities of all. Mertensio maritimae–Honcke­nyion diffusae. The sea influence gradually decrea­ses, but amount of seaweed debris is still high on the coastal sand dunes that is a common place for ass. Honckenyo diffusae–Leymetum arenarii. The communities of Ligusticum scoticum–Festuca rubra com. type cover the higher-level beaches. The nitrophilous species are common for low-level beaches but they are almost absent in high-level phytocoenoses which are considered being an intermediate stage between monodominant seashore grasslands of ass. Honckenyo diffusae–Leymetum arenarii and multispecies high-level seashore meadows (Koroleva et al., 2011). The Rybachiy and Sredniy peninsulas coastal ve­getation seems to be common with another arctic/subarctic areas but having more similarities with western coasts. Communities of ass. Atriplicetum lapponicae have not been marked for Murmansk region, and probab­ly do not occur to the east of the peninsulas (Koroleva, 2006; Koroleva et al., 2011; Matveyeva, Lavrinenko, 2011). However, they are common in western areas (Northern Norway and apparently Iceland) (Tüxen, 1970; Thannheiser, 1974). Silty and sandy low-level salt marshes belong to ass. Puccinellietum phryganodis. Ass. Puccinellietum coarctatae (syn. Puccinellietum retroflexae Nordh. 1954) communities are found on the shingle low and middle level salt mar­shes. The further decreasing of salt seawater influence results in ass. Junco gerardii–Caricetum glareosae community formation. They occupy middle and high level of salt marshes. Communities of associations Puccinellietum phryganodis and Puccinellietum coarctatae on low and middle salt marsh levels are widespread in arctic and subarctic zones (Thannheiser, 1974; Koroleva et al., 2011; Matveyeva, Lavrinenko, 2011). There is an interesting notice that communities of widespread ass. Caricetum subspathaceae were not found on the studied area. The diagnostic species of this association – Carex subspathacea – vegetated only in Junco gerardii–Caricetum glareosae communities. The reason of such phenomenon could be a small area occupied by salt marsh communities on the Rybachiy and Sredniy peninsulas, which turns out that all vegetation types cannot completely evolve.


Bothalia ◽  
2003 ◽  
Vol 33 (1) ◽  
pp. 121-134 ◽  
Author(s):  
F. Siebert ◽  
G. J. Bredenkamp ◽  
S. J. Siebert

Data from fifteen phytosociological studies were merged and classified to describe and compare the vegetation of geo­graphically separated and climatically different Mopanev eld types in South Africa. Namibia and Zimbabw e. Seven v egetation types and ten major plant communities were identified using TW INSPAN. Vegetation types were separated according to geo­graphical regions. There were significant floristic affinities even though there w ere geological and climatic differences between the regions. Plant communities were described according to vegetation structure, habitat and floristic composition. Although environmental data were not adequate for a detailed ordination. DECORANA reflected the distribution of vegetation types and major plant communities along environmental gradients. Limitations of large phytosociological syntheses were also addressed. Species richness (alpha diversity) was calculated for each geographical region. The Musina (Messina) region north of the Soutpansberg. South Africa, has the highest species richness, and Kaokoland. Namibia, the lowest Due to irregular annual rainfall patterns in semi-arid Mopaneveld, it is suggested that variance in species richness is associated with temporal vegeta­tion states induced by rainfall events. Species richness of Mopaneveld was further compared w ith other sav anna types.


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