Composition and structure of Gastropoda in the Lavandula dentata L. (Labiatae) stations in the Ghazaouet region (Tlemcen, North-West Algeria)

2021 ◽  
Vol 9 (1) ◽  
pp. 22-29
Author(s):  
Amina DAMERDJI ◽  
◽  
Keyword(s):  
Species Richness ◽  
Vertical Distribution ◽  
Coastal Region ◽  
Relative Importance ◽  
North West ◽  
Terrestrial Gastropods ◽  
Composition And Structure ◽  
West Algeria

An approach to the diversity of malacofauna associated with toothed lavender was carried out in three stations belonging to the coastal region of Ghazaouet (Wilaya de Tlemcen) from January to July 2013. The specific richness of gastropods is 14 species. Four species are accessories and ten others are accidental. The relative importance of snails varies by station and by month and season. Gastropods preferring certain humidity are easily collected in winter and spring. In April, the species richness is relatively important (6 species) in the 1st and 2nd stations respectively. Milax gagates has a frequency of 78.57% in the first station (Sidi-Aissa) and 57.14% in the 2nd station (Sidi - Amar). Helicella pyramidata has a frequency of 35.71% in station 3 (Bab Khroufa). Similarly, this Helicellinae has a density equal to 0.50 in the same station. Keywords: Lavandula dentata, terrestrial gastropods, diversity, bioecology, vertical distribution, Ghazaouet region (Tlemcen).

scholarly journals SPECIES RICHNESS AND ABUNDANCE OF LOW-TRUNK HERB EPIPHYTES IN RELATION TO HOST TREE SIZE AND BARK TYPE, EASTERN AMAZONIA

2015 ◽  
Vol 39 (3) ◽  
pp. 457-466 ◽  
Author(s):  
José Leonardo Lima Magalhães ◽  
Maria Aparecida Lopes
Keyword(s):  
Species Richness ◽  
Vertical Distribution ◽  
Tropical Rainforest ◽  
Tree Size ◽  
Host Tree ◽  
Positive Correlation ◽  
Suitable Substrate ◽  
Composition And Structure ◽  
Species Richness And Abundance ◽  
Herb Species

ABSTRACTThe composition and structure of the low-trunk epiphytic herb assembly as well as its vertical distribution were studied. DBH of host tree and bark type influence species richness and abundance in a nonlooded lowland tropical rainforest in Eastern Amazonia (1º57’36"S 51º36’55"W). A total of 37 epiphytic herb species were identified, among which 60% were Araceae. Species richness and abundance of epiphytic herbs showed tendency of positive correlation with host tree size and no relationships with bark type. Low positive correlation may be a by-product of the predominance of trees with smaller diameter in our sample rather than a reflection of neutral relationship. The absence of relationships with bark type may be partially explained by the large number of secondary, generalist, hemi-epiphytes and also may reflect the absence of suitable substrate in trees with smaller diameter.

scholarly journals Disentangling the Ecological Determinants of Species and Functional Trait Diversity in Herb-Layer Plant Communities in European Temperate Forests

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 552
Author(s):  
Janez Kermavnar ◽  
Lado Kutnar ◽  
Aleksander Marinšek
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Plant Communities ◽  
Functional Trait ◽  
Forest Stand ◽  
Relative Importance ◽  
Herb Layer ◽  
Bud Bank ◽  
Tree Species Composition ◽  
Stand Characteristics

Forest herb-layer vegetation responds sensitively to environmental conditions. This paper compares drivers of both taxonomic, i.e., species richness, cover and evenness, and functional herb-layer diversity, i.e., the diversity of clonal, bud bank and leaf-height-seed plant traits. We investigated the dependence of herb-layer diversity on ecological determinants related to soil properties, climatic parameters, forest stand characteristics, and topographic and abiotic and biotic factors associated with forest floor structure. The study was conducted in different forest types in Slovenia, using vegetation and environmental data from 50 monitoring plots (400 m2 each) belonging to the ICP Forests Level I and II network. The main objective was to first identify significant ecological predictors and then quantify their relative importance. Species richness was strongly determined by forest stand characteristics, such as richness of the shrub layer, tree layer shade-casting ability as a proxy for light availability and tree species composition. It showed a clear positive relation to soil pH. Variation in herb-layer cover was also best explained by forest stand characteristics and, to a lesser extent, by structural factors such as moss cover. Species evenness was associated with tree species composition, shrub layer cover and soil pH. Various ecological determinants were decisive for the diversity of below-ground traits, i.e., clonal and bud bank traits. For these two trait groups we observed a substantial climatic signal that was completely absent for taxonomy-based measures of diversity. In contrast, above-ground leaf-height-seed (LHS) traits were driven exclusively by soil reaction and nitrogen availability. In synthesis, local stand characteristics and soil properties acted as the main controlling factors for both species and trait diversity in herb-layer communities across Slovenia, confirming many previous studies. Our findings suggest that the taxonomic and functional facets of herb-layer vegetation are mainly influenced by a similar set of ecological determinants. However, their relative importance varies among individual taxonomy- and functional trait-based diversity measures. Integrating multi-faceted approaches can provide complementary information on patterns of herb-layer diversity in European forest plant communities.

Systematic Position of Pistacia atlantica Desf. Subsp. atlantica in North-West Algeria: Anatomy and Biometry of Leaves

2020 ◽  
Vol 4 (1) ◽  
pp. 48-53
Author(s):  
Mohamed Amara ◽  
Mohammed Bouazza ◽  
Kheira Errouane ◽  
Meriem Kaid-Harche ◽  
Djamel Nafil ◽  
...  
Keyword(s):  
Natural Resources ◽  
Large Scale ◽  
Systematic Position ◽  
Pistacia Atlantica ◽  
North West ◽  
Anthropic Activity ◽  
West Algeria

Abstract The area of Algerian western north already subjected to a strong climatic rigour and an excessive anthropic activity for several decades, has been confronted with the threats of the alarming degradation of its natural resources, following the example Pistacia atlantica which occupies today only one quite thin proportion of the territory. The study method was based on the phytoecological approach on a very large scale by approaching the anatomical and biometric study of the leaves of Pistacia atlantica in order to identify and confirm the name of the subspecies. The analysis of the results obtained revealed that this subspeciesis atlantica, phenotypically very variable.

scholarly journals Interference competition pressure predicts the number of avian predators that shifted their timing of activity

2018 ◽  
Vol 285 (1880) ◽  
pp. 20180744 ◽  
Author(s):  
Yifan Pei ◽  
Mihai Valcu ◽  
Bart Kempenaers
Keyword(s):  
Species Richness ◽  
Body Size ◽  
Interference Competition ◽  
Relative Importance ◽  
Exploitation Competition ◽  
Predator Species ◽  
Avian Predator ◽  
Avian Predators ◽  
Time Partitioning ◽  
Competition Pressure

Being active at different times facilitates the coexistence of functionally similar species. Hence, time partitioning might be induced by competition. However, the relative importance of direct interference and indirect exploitation competition on time partitioning remains unclear. The aim of this study was to investigate the relative importance of these two forms of competition on the occurrence of time-shifting among avian predator species. As a measure of interference competition pressure, we used the species richness of day-active avian predator species or of night-active avian predator species (i.e. species of Accipitriformes, Falconiformes and Strigiformes) in a particular geographical area (assemblage). As an estimate of exploitation competition pressure, we used the total species richness of avian predators in each assemblage. Estimates of the intensity of interference competition robustly predicted the number of Accipitriformes species that became crepuscular and the number of Strigiformes species that became day-active or strictly crepuscular. Interference competition pressure may depend on body size and on the total duration of the typical active period (day or night length). Our results support—to some extent—that smaller species are more likely to become time-shifters. Day length did not have an effect on the number of time-shifter species in the Accipitriformes. Among the large Strigiformes, more time-shifter species occur in areas where nights are shorter (i.e. where less of the typical time resource is available). However, in the small Strigiformes, we found the opposite, counterintuitive effect: more time-shifters where nights are longer. Exploitation competition may have had an additional positive effect on the number of time-shifters, but only in Accipitriformes, and the effect was not as robust. Our results thus support the interference competition hypothesis, suggesting that animals may have shifted their time of activity, despite phylogenetic constraints on the ability to do so, to reduce the costs of direct interactions. Our findings also highlight the influence of body size as a surrogate of competitive ability during encounters on time partitioning, at least among avian predators.

scholarly journals COMPARISON ON VEGETATION COMPOSITION AND STRUCTURE OF EXCLOSURES VS. OPEN GRAZING LANDS IN NORTHERN ETHIOPIA

2021 ◽  
Vol 9 (8) ◽  
pp. 70-99
Author(s):  
Samson Shimelse Jemaneh
Keyword(s):  
Population Structure ◽  
Species Richness ◽  
Plant Species ◽  
Woody Species ◽  
Soil Parameters ◽  
Northern Ethiopia ◽  
Indigenous Species ◽  
Regeneration Status ◽  
Composition And Structure ◽  
Grazing Lands

This study was conducted with the objectives of study investigates, compare, and try to describe the floristic composition and structure of the vegetation of exclosures and open grazing lands. A stratified preferential sampling design technique with flexible systematic model was used for data collection. Data on vegetation and environmental parameters were gathered from 120 quadrants (90 from restorations or exclosures of different ages and 30 from adjacent open grazing lands), of 20 m x 20 m (400 m2) size. Species richness and the presence or absence of herbaceous plants were recorded like soil samples in a 2 m x 2 m (4 m2) subplot inside each main quadrant from five points, one at each corner and one at the center.  A total of 142 plant species belonging to 118 genera and 52 families were identified. All exclosures displayed higher plant species richness, diversity, and aboveground standing biomass compared to the adjacent open grazing lands. Consideration of edaphic (e.g. soil total nitrogen, available phosphorus, CEC, exchangeable bases, soil pH and soil texture) and site (e.g. Stoniness, Grazing) variables will help to optimize the selection of areas for the establishment of future exclosures. Moreover, our study suggests that with time exclosures may increasingly obtain an important role as refugees and species pool similar to church forests and should be protected and managed in a sustainable manner. However, economic and social impacts of exclosures should be included in feasibility studies before establishing exclosures in the future.  Altitude, Grazing and some soil parameters like Mg were the major environmental factors in the division of the vegetation into plant community types. The result of the frequency distribution of woody species showed a high proportion of small-sized individuals in the lower diameter classes indicating good recruitment potential of the forest patches and the rare occurrence of large individuals. Such trend was probably caused by past disturbance of the original vegetation resulting in a succession of secondary vegetation. In addition, the analysis of species population structure indicated that some tree species had abnormal population structure with no or few individuals at lower size classes. Moreover, assessment of regeneration status on the basis of age classes indicated that significant proportion of woody species were represented by few or no seedlings, entailing that they were under threat. Substantial numbers of forest species were found to have irregular population structure and are in reduced regeneration status. To prevent local extinction of these species, present efforts of nursery establishment and plantation of indigenous species in the exclosures should be strengthened and extended.

scholarly journals EPIDEMIO-GENETIC CHARACTERIZATION OF THE POPULATION OF TLEMCEN (NORTH-WEST ALGERIA) BY TRISOMY 21

2018 ◽  
Vol 3 (1) ◽  
pp. 235-235
Author(s):  
Houari Hamdaoui Houari Hamdaoui ◽  
Ammaria Aouar Ammaria Aouar ◽  
Djamel Belkhatir Djamel Belkhatir ◽  
Zakarya Moqaddem Zakarya Moqaddem ◽  
Sarra Khater Sarra Khater ◽  
...  
Keyword(s):  
Trisomy 21 ◽  
Genetic Characterization ◽  
North West ◽  
West Algeria

Composition and structure algal сommunity of the Сát Tiên National Park, Southern Vietnam (first data)

2021 ◽  
pp. 78-85
Author(s):  
Elena M. Kezlya ◽  
Anton M. Glushchenko ◽  
Yevhen I. Maltsev ◽  
Svetlana Y. Maltseva ◽  
Evgeniy S. Gusev ◽  
...  
Keyword(s):  
Species Composition ◽  
Vertical Distribution ◽  
Forest Soils ◽  
National Park ◽  
Soil Horizons ◽  
Southern Vietnam ◽  
South Vietnam ◽  
Composition And Structure ◽  
Cat Tien National Park

The report presents the results of a study of algae in forest soils in the Cat Tien National Park (South Vietnam) using 7 model sites as an example. The species composition of algae and their vertical distribution in the soil horizons have been characterized.

Recovery of shrubland communities on abandoned farmland in southwestern Australia: soils, plants, birds and arthropods

1999 ◽  
Vol 5 (3) ◽  
pp. 163 ◽  
Author(s):  
G. W. Arnold ◽  
M. Abensperg-Traun ◽  
R. J. Hobbs ◽  
D. E. Steven ◽  
L. Atkins ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Plant Species ◽  
Bird Species ◽  
Sandy Soils ◽  
Residual Effects ◽  
Ecosystem Recovery ◽  
Farming History ◽  
Passive Recovery ◽  
Composition And Structure

Passive recovery of land formerly used for agricultural production may be an inexpensive and rapid method of ecosystem recovery, and may provide an alternative method to active revegetation. Passive recovery may also contribute to sustainable agriculture (soil salinity). For undisturbed and disturbed areas of the central wheatbelt of Western Australia, this paper reports the effects of farming history (clearing only, cultivation, duration of farming, and time since farming ceased) on the soil nutrient content, plant floristics (richness and composition) and structure, and the abundance, species richness and species composition of birds and arthropods. Only one site was cultivated for >6 years. We summarize as follows: (1) Previous clearing and cultivation has left no residual effects on the nitrogen or phosphorus content in the sandy soils. (2) There were no significant differences in terms of plant species richness but some differences in cover of woody plants, grass cover and plant species composition for farming history or time since farming ceased. (3) There were no significant differences in bird species richness but differences in species composition for time since farming ceased. (4) Arthropods showed few (and low) significant differences in their abundance, richness or species composition across different farming histories and time periods since farming ceased. Farming of these shrublands has left only minor changes in the composition and structure of the vegetation, and in the abundance, species richness and species composition of the passerine bird and arthropod assemblages. Abandoned parcels of land on the sandy soils which support shrubland may yield useful conservation benefits with relatively little input.

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