Trends in vegetation cover in the grassland community on the Bogong High Plains, Victoria.

1985 ◽  
Vol 7 (2) ◽  
pp. 93 ◽  
Author(s):  
Rees H van ◽  
WA Papst ◽  
K McDougall ◽  
RC Boston
Keyword(s):  
Species Composition ◽  
Plant Species ◽  
Vegetation Cover ◽  
The Other ◽  
Alpine Grassland ◽  
High Plains ◽  
Grassland Community ◽  
Major Species ◽  
A Site ◽  
Free Ranging

Cover and luxuriance of plant species in the alpine grassland community were measured. Four grassland sites were monitored regularly from 1979 to 1984; three are grazed during summer months by free-ranging cattle, the other has not been grazed since 1974. Data are presented for cover of major species at another grazed site monitored since 1947. Three classes of total vegetation cover were defined in relation to the susceptibility of a site toerosion. Results show that there have been no trends in vegetation cover and luxuriance. Species composition and total vegetation cover varied between sites but there were no dis- cernible trends in these characteristics.

scholarly journals Recording plant status and regeneration during single visits

2019 ◽  
Vol 1 (4) ◽  
pp. 283-291
Author(s):  
Kevin J. Walker ◽  
Simon Leach ◽  
Chris Preston ◽  
Thomas Humphrey ◽  
Trevor James ◽  
...  
Keyword(s):  
Plant Species ◽  
Native Species ◽  
Objective Measure ◽  
The Other ◽  
A Site

Information on the origin (status) and regeneration of plant species improves our understanding of native distributions and the establishment of non-native species. However, current categories used to record status in Britain and Ireland, whilst conceptually informative, rely on a knowledge of persistence that is impossible to assess objectively during a single (one-off) recording visit. We propose five alternative categories that focus on origin (how a species arrived at a site) rather than persistence. The first two categories apply to nationally native taxa: (1) populations that are unequivocally native and (2) those that are likely to have been introduced and/or are spreading for reasons that are obscure. The other three categories cover the occurrences of any taxon, native or non-native, that is known or suspected to have been introduced to a site: (3) introductions with unknown/obscure origins; (4) deliberate introductions; and (5) accidental introductions. For the introduced categories 3-5 we recommend that botanists also record signs of regeneration, i.e. seedlings or widely scattered patches, as a more objective measure whether a species is likely to be self-sustaining in a given locality.

The putative impact of exploitation on rocky infratidal macrofaunal assemblages: a multiple-area comparison

1999 ◽  
Vol 79 (1) ◽  
pp. 23-34 ◽  
Author(s):  
Theresa Lasiaka
Keyword(s):  
South Africa ◽  
Species Composition ◽  
Multidimensional Scaling ◽  
Functional Groups ◽  
Regional Differences ◽  
Southern Region ◽  
The Other ◽  
Major Species ◽  
Northern Regions ◽  
The Right

The putative impact of subsistence foragers along the Transkei coast of South Africa was determined by comparing the community-level attributes of infratidal macrofaunal assemblages in three ‘no-take’ reserves with those at adjacent exploited localities. The objective of this study was to ascertain whether the differences in the assemblages found at exploited and non-exploited localities were consistent along this coast. Two-way ANOVAs indicated that the presence/absence of exploitation had no effect on univariate community measures. Macrofaunal biomass was the only measure which showed significant differences amongst locations and interaction effects. Abundance/biomass comparison curves revealed that all the exploited sites except one showed the configuration typical of moderately disturbed sites and that all the non-exploited sites except one showed the trend typical of undisturbed sites. Two-way crossed ANOSIM tests indicated that treatment and location both had significant effects on these assemblages and that there were also significant differences between each pair of locations. The latter probably reflects regional differences in species composition due to the fact that this coast lies at the junction of two zoogeographic marine provinces. The multidimensional scaling (MDS) ordinations derived from abundance and biomass estimates revealed two major clusters of sites, one representing sites in the southern region and the other sites within the central and northern regions. The non-exploited sites within each region were situated above and to the right of the corresponding exploited sites. Similarity percentage analyses (SIMPER) indicated that the major species contributing to the average dissimilarity between the exploited and non-exploited localities varied regionally. There was, however, a fair amount of consistency in terms of the functional groups highlighted by these analyses. Some of the species adversely affected by exploitation are dependent on primary substrata either for their food supplies or for attachment. Likewise many of the species which appeared to benefit from exploitation were phytal-associated forms.

scholarly journals Effects of Soil Physico-Chemical Properties on Plant Species Composition and Diversity Along an Elevation Gradient Over Alpine Grassland on the Qinghai-Tibetan Plateau, China

2021 ◽  
Author(s):  
Wangya Han ◽  
Li Chen ◽  
Xukun Su ◽  
Dan Liu ◽  
Tiantian Jin ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Nitrogen Content ◽  
Plant Species ◽  
Chemical Properties ◽  
Alpine Grassland ◽  
Plant Species Composition ◽  
Available Nitrogen ◽  
Physico Chemical ◽  
Soil Available Nitrogen

Abstract Background and aims Alpine grassland on the Qinghai-Tibetan Plateau (QTP) is sensitive and fragile, and it is subject to serious degradation. It is essential to determine the effects of soil parameters on plant species to explain grassland degradation. Methods We classified plant communities into six types based on hierarchical clustering. Then we analyzed the effects of soil physico-chemical properties on plant species composition and diversity by canonical ordination and spatial regression from an elevation perspective. Results Elevation class had significant effects on soil moisture content, soil pH, and soil available nitrogen content. The primary soil parameter affecting plant species composition and diversity in alpine grassland was soil available nitrogen content. The effect of soil available nitrogen content on plant species richness varied at different elevations. For Gramineae plants (G), plant species richness declined with the increase in soil available nitrogen content at low elevation, but rose at middle elevation. Soil available nitrogen content had a more significant limiting effect on species richness at high elevation. Conclusion Analyzing the relationship between plant species and soil physico-chemical properties increases our understanding of grassland degradation, and will improve grassland restoration programs and responses to climate change.

PERENNIAL MONITORING OF A PASTURE DEPRESSION DEVELOPMENT UNDER DIFFERENT LOADS OF THE TERSKO-KUMSKAYA LOWLAND

1970 ◽  
pp. 15-18
Author(s):  
М. А. Babaeva ◽  
S. V. Osipova
Keyword(s):  
Species Composition ◽  
Plant Species ◽  
Plant Communities ◽  
Vegetation Cover ◽  
Climatic Factors ◽  
Atmospheric Precipitation ◽  
Anthropogenic Pressure ◽  
Dominant Plant Species ◽  
Composition And Structure

Changes in phytocenoses in the long-term regime under the influence of anthropogenic pressure, natural and climatic factors are considered. Under the conditions of growing external influence the ordinary components of the community are transformed into its dominant synanthropic forms. Geobotanical studies have shown the heterogeneity of the vegetation cover of pastures in terms of phytocenotic composition, which is in a state of severe disruption. The long-term monitoring studies of pastures show that a complex of environmental factors has a significant impact on the change in species composition and structure under various loads. Change in the vegetation cover under the influence of weak grazing is disappearance of large-sod grasses of the Stipa series with a predominance of small-sod grasses such as Festuca sulcata. Intensive grazing causes disappearance of Festuca sulcata, as well as appearance of small Artemisia shrubs and more competitive plant species that cause changes in plant communities. Such changes make it possible to determine the dominant plant species, during the development of which the next transition of penetration into plant communities of other species begins. The phytocenoses of the compared species of this region differ in the structure and productivity of the dominant forage plants which give the highest phytomass depending on the humidity of the period and the type of load. The purpose of this work is to show the long-term influence of climatic factors in the absence of a minimum of atmospheric precipitation, as well as anthropogenic influences on the transformation of phytocenoses, changes in the structure of the vegetation cover of the semi-desert at different stages of loading. The article presents research data for several years on the species composition and productivity of pastures, depending on the load by the seasons of the year. The results of monitoring studies have established the number of dominant species and their productivity of phytocenoses at different stages of development of vegetation degradation.

scholarly journals The problem of maintaining large herbivores in small conservation areas: deterioration of the grassveld in the Addo Elephant National Park

Koedoe ◽  
1991 ◽  
Vol 34 (1) ◽  
Author(s):  
P. Novellie ◽  
A.J. Hall-Martin ◽  
D. Joubert
Keyword(s):  
Species Composition ◽  
Relative Abundance ◽  
Vegetation Cover ◽  
National Park ◽  
Dwarf Shrub ◽  
Grass Cover ◽  
Conservation Areas ◽  
Large Herbivores ◽  
Themeda Triandra ◽  
Grassland Community

Changes in vegetation cover and species composition in a grassland community during a six year period are reported. The grass Themeda triandra and the dwarf shrub Helichrysum rosum decreased in abundance, whereas the grass Eragrostis obtusa increased. Comparison of grazed plots with fenced plots revealed large herbivores were responsible for the increase in abundance ofE. obtusa. The abundance of T. triandra was influenced by large herbivores, but rainfall fluctuations apparently also played a role. The decline in relative abundance of/7. rosum was evidently not caused by large herbivores. Grass cover was closely determined by rainfall. A drought-induced decline in forage abundance evidently caused the buffalo population to crash.

Actualisation du catalogue des pteridophytes du Nord Ouest Algerien (region de Tlemcen). An update of the cheklist of pteridophytes from Nordwest Algeria (Tlemcen region)

2013 ◽  
Vol 38 ◽  
pp. 33-39 ◽  
Author(s):  
Boumediene Medjahdi ◽  
Assia Ltreuch-Belarouci ◽  
Rémy Prelli
Keyword(s):  
Nous Avons ◽  
Genetic Resources ◽  
Threatened Species ◽  
The Other ◽  
Natural Distribution ◽  
Ecological Characteristics ◽  
Statutory Protection ◽  
Ouest Algérien ◽  
A Site ◽  
Ressources Génétiques

Français. Un inventaire des ptéridophytes a été entrepris dans les forêts de la région de Tlemcen. L’inventaire de ces populations constitue une étape importante pour le développement des stratégies de conservation des ressources génétiques et de la diversité de ces populations sur l’ensemble de leur aire de distribution naturelle. Nous avons ainsi effectué le recensement et l’identification des fougères existantes dans la région de Tlemcen. Au total, plusieurs stations dont les caractéristiques écologiques diffèrent d’un site à un autre ont été prospectées, cela a permis l’identification de 26 taxons (dont 5 exceptionnellement rare). La création de réserves naturelles forestières renforcée par une protection réglementaire des espèces les plus menacées est nécessaire pour le maintien de ces communautés si particulières. English. An inventory of Pteridophyta was begun in the forests of the Tlemcen region. The inventory of these populations constitutes an important stage for the developement of the strategies of preservation of the genetic resources and the diversity of these populations on their whole area of natural distribution. We so made the inventory and the identification of the existing ferns in the region of Tlemcen. On the whole, several stations the ecological characteristics differ from a site in the other one were canvassed; they allowed the identification of 26 taxes (among which 5 exceptionally rare). The creation of forest nature reserves strengthened by a statutory protection of the most threatened species is necessary for the preservation of these particular communities.

MOSAICITY OF THE VEGETATION COVER OF THE KOCHUBEY BIOSPHERE STATION PASTURES

1970 ◽  
pp. 40-42
Author(s):  
М. А. Babaeva ◽  
S. V. Osipova
Keyword(s):  
Plant Species ◽  
Vegetation Cover ◽  
Cynodon Dactylon ◽  
Plant Cover ◽  
Avena Fatua ◽  
Living Environment ◽  
Anthropogenic Factors ◽  
Indigenous Species ◽  
Fodder Plants ◽  
Falcaria Vulgaris

The regularities of changes in the resistance of different groups of fodder plants to adverse conditions were studied. This is due to the physiological properties that allow them to overcome the harmful effects of the environment. As a result of research species - plant groups with great adaptive potential to the harsh continental semi-desert conditions were identified. Monitoring observation and experimental studies showed too thin vegetation cover as a mosaic, consisting of perennial xerophytic herbs and semishrubs, sod grasses, saltwort and wormwood, as well as ephemera and ephemeroids under the same environmental conditions, depending on various climatic and anthropogenic factors. This is due to the inability or instability of plant species to aggressive living environment. It results in horizontal heterogeneity of the grass stand, division into smaller structures, and mosaic in the vegetation cover of the Kochubey biosphere station. The relative resistance to moderate stress was identified in the following species from fodder plants Agropyron cristatum, A. desertorum, Festuca valesiaca, Cynodon dactylon, Avena fatua; as for strong increasing their abundance these are poorly eaten plant species Artemisia taurica, Atriplex tatarica, Falcaria vulgaris, Veronica arvensis, Arabidopsis thaliana and other. On the site with an increasing pressure in the herbage of phytocenoses the number of xerophytes of ruderal species increases and the spatial structure of the vegetation cover is simplified. In plant communities indigenous species are replaced by adventive plant species. The mosaic of the plant cover of phytocenoses arises due to the uneven distribution in the space of environmental formation, i.e. an edificatory: Salsola orientalis, S. dendroides, Avena fatua, Cynodon dactylon, Artemisia taurica, A. lercheanum, Xanthium spinosum, Carex pachystyli, under which the remaining components of the community adapt. Based on the phytocenotic indicators of pasture phytocenoses it can be concluded that the vegetation cover is in the stage of ecological stress and a decrease in the share of fodder crops and an increase in the number of herbs indicates this fact.

scholarly journals Photosynthetic parameters of a sedge-grass marsh as a big-leaf: effect of plant species composition

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Markéta Mejdová ◽  
Jiří Dušek ◽  
Lenka Foltýnová ◽  
Lenka Macálková ◽  
Hana Čížková
Keyword(s):  
Species Composition ◽  
Plant Species ◽  
Photosynthetic Parameters ◽  
Acorus Calamus ◽  
Dominant Plant Species ◽  
Local Plant ◽  
Rate Of Photosynthesis ◽  
Carex Acuta ◽  
Leaf P

AbstractThe study estimates the parameters of the photosynthesis–irradiance relationship (PN/I) of a sedge-grass marsh (Czech Republic, Europe), represented as an active “green” surface—a hypothetical “big-leaf”. Photosynthetic parameters of the “big-leaf” are based on in situ measurements of the leaf PN/I curves of the dominant plant species. The non-rectangular hyperbola was selected as the best model for fitting the PN/I relationships. The plant species had different parameters of this relationship. The highest light-saturated rate of photosynthesis (Asat) was recorded for Glyceria maxima and Acorus calamus followed by Carex acuta and Phalaris arundinacea. The lowest Asat was recorded for Calamagrostis canescens. The parameters of the PN/I relationship were calculated also for different growth periods. The highest Asat was calculated for the spring period followed by the summer and autumn periods. The effect of the species composition of the local plant community on the photosynthetic parameters of the “big-leaf” was addressed by introducing both real (recorded) and hypothetical species compositions corresponding to “wet” and “dry” hydrological conditions. We can conclude that the species composition (or diversity) is essential for reaching a high Asat of the “big-leaf ”representing the sedge-grass marsh in different growth periods.

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