Temat: diversity parameter - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Botanical Diversity of Arid Steppe in South East of Algeria (Biskra)
Autorzy:: Belhadj, Amina
Allache, Fatma Demnati
Boulghobra, Nouar
Mebrek, Naima
Powiązania:: https://bibliotekanauki.pl/articles/2202318.pdf
Data publikacji:: 2023
Wydawca:: Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:: plant diversity
diversity parameter
arid steppe
plant community
Opis:: In the light of climate change, it is important to acquire the information on the diversity of flora in order to ensure rational use of steppe rangelands. The present study aimed at diagnosing the botanical and the taxonomic diversity of the arid steppe plant communities in South East of Algeria. A total of 216 phytoecological sampling, were collected in three sites and one sample for each month during 2017 and 2018. The vegetation was analyzed using various species diversity parameters (abundance, species richness, life forms, alpha and beta diversity indices and disturbance index). Results show that 985 plant individuals were classified into 27 species, 27 genera and 14 families, with predominance of Chenopodiaceae and Asteraceae in the arid steppe of El-Haouch, and remarkable dominance of Chamaephytic and Therophytic plants in different phytoecological groups. The state of vegetation degradation in a susceptible environment on Algeria’s rangeland in the South East which is confirmed by the low values of Shannon, Jaccard indices and the values of disturbance index ranged between 50 and 85.71%. The alpha diversity parameters of the different phytoecological groups have low values, which reflect a more fragile homogeneous ecosystem, unfavorable life conditions and the absence of certain species of high pastoral value.
Źródło:: Journal of Ecological Engineering; 2023, 24, 1; 120--134
2299-8993
Pojawia się w:: Journal of Ecological Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Phytoplankton Diversity and Abundance in Relation to Physico-chemical Parameters of Ifewara Reservoir, Southwestern Nigeria
Autorzy:: Hameed, I. O.
Adeniyi, I. F.
Adesakin, T. A.
Aduwo, A. I.
Powiązania:: https://bibliotekanauki.pl/articles/1076734.pdf
Data publikacji:: 2019
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:: Phytoplankton abundance
distribution
diversity
physico-chemical parameter
Opis:: The phytoplankton abundance and physico-chemical parameters of Ifewara Reservoir, Southwestern Nigeria was studied for four months (February to December, 2015). Four sampling stations (designated Stations 1-4) were established along the horizontal axis of the reservoir - from inflow region to the dam site end. At each station, net plankton samples were collected by sieving 30 litres of water through a plankton net of 50 µm mesh size into 30 ml concentrate volume. These were then preserved in 5% formalin solution and later treated with Lugol’s solution and reduced to 3 ml for microscope observation. The results of the physico-chemical parameters showed that some were above recommended limits of the National Environmental Standards and Regulations Enforcement Agencies (NESREA) for drinking water and aquatic life. Sixty-nine (69) species of phytoplankton were recorded from the four investigated sampling stations. The abundance of phytoplankton was in the following order; Bacillariophyceae (90.84%) > Chlorophyceae (44.67%) > Cyanophyceae (10.69%) > Charophyceae (0.31%) > Euglenophyceae (0.12%) > Dinophyceae (0.06%) > Chrysophyceae (0.03%). The most abundant phytoplankton species was Fragilaria aceania, accounting for 74.28% of the total, followed by Cosmarium quadrum (13.04%), Rhizoclonium hieroglyphicum (11.97%) and Oscillatoria tenuis (8.03%). With regard to the horizontal pattern of variation along the reservoir, the highest phytoplankton abundance was recorded at the inflow basin and the lowest abundance at the dam site. Almost all the phytoplankton groups also had their highest mean abundance during the rainy season rather then during the dry season.
Źródło:: World News of Natural Sciences; 2019, 24; 250-267
2543-5426
Pojawia się w:: World News of Natural Sciences
Dostawca treści:: Biblioteka Nauki