ABSTRACTS 2026 #2                                  
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Nadhra BOUKROUMA, Hind MOUKATEL

Abstract. Understanding the mechanisms governing community assembly of waterbirds in Mediterranean wetlands is critical for biodiversity conservation, yet the relative influence of biological phenology versus habitat structural complexity remains poorly quantified in North African artificial aquatic ecosystems. This study characterizes waterbird community organization at Battoum Marsh (hill reservoir, north-east Algeria) to evaluate how temporal dynamics and habitat heterogeneity partition avian distribution. Utilizing Scheirer–Ray–Hare tests and multivariate ordination, we demonstrate that the biological period of listed species of waterbirds is the overarching keydeterminant of community assembly, exerting a significantly greater influence on alpha diversity (H=17.79, p<0.001) than vegetation type (p=0.83). Phenologram and ridgeline analysis reveals that the wintering period is defined by high dominance and dense aggregations of Rallids (e.g. Fulica atra) within Typha latifolia and Phragmites australis standssupporting the thermal-cover hypothesis. Conversely, the breeding period marks a transition toward spatial homogeneity and increased evenness, signifying a functional shift from resource-dependent clustering to territoriality-mediated dispersion. We identify a migratory dip during the pre-nuptial phase, characterized by diminished site fidelity and abundance. Crucially, while temporal cycles govern broad richness metrics, the stochastic interaction between period and vegetation type underpins species identity; habitat specialists, such as the Northern Pintail (Anas acuta), exhibit an obligate reliance on specific habitat-period niches during the pre-nuptial phase, whereas generalists like the Common Moorhen (Gallinula chloropus) demonstrate high aquatic birds. These findings refine the habitat heterogeneity hypothesis by illustrating that in fluctuating Mediterranean artificial wetlands, temporal turnover and migratory flux are the dominant structuring forces of waterbird communities. By advocating for the protection of phenological corridors and successional mosaics over static conservation mapping, this study provides a mechanistic framework for adaptive management in North African wetlands facing climate-driven hydrological instability.

Keywords: alpha diversity; community assembly; aquatic birds; mediterranean wetlands; phenological nodesin
DOI: https://doi.org/10.61215/auofb.2026.2.01 




Amel HEROUINI, Rekia CHERIF, Imane HAMEL, Faredj CHIKHI, Abdellah KEMASSI

Abstract. Beetles of the species Tribolium are serious pests in cereal storage, causing economic losses and impairing the quality of the grain during storage. Plant extracts, such as aqueous extracts of Pergularia tomentosa L., are currently being studied as possible alternatives to synthetic insecticides for controlling these pests. Phytochemical screening of Pergularia tomentosa revealed a richness in bioactive secondary metabolites, in particular flavonoids, saponosides, terpenes, sterols, alkaloids and free quinones. Bioassays carried out on two species of beetle (Tribolium castaneum and T. confusum) revealed strong insecticidal activity, with efficacy varying depending on the dose and method of application (ingestion or contact). The aqueous extract of P. tomentosa exhibited pronounced insecticidal activity when applied directly, producing mortality rates of 63.33–86.67% through ingestion and 86.67–100% through contact exposure. Mortality generally appeared after 48 h at high concentrations. Evaluation using traditional toxicological parameters (mortality rate, LD50 and LT50) confirmed the efficacy of the extracts, in particular the acetone and methanol fractions, which induced up to 90% mortality after 72 hours. These results confirm the strong biocidal potential of P. tomentosa against Tribolium imagos.

Keywords: aqueous extracts; insecticidal activity; Pergularia tomentosa; phytochemical screening; Sahara.
DOI: https://doi.org/10.61215/auofb.2026.2.02




Sid Ahmed SAADI, Hafsa YAICHE ACHOUR, Nadjette DJEMOUAI, Noureddine BOURAS, Atika MEKLAT

Abstract. Actinobacteria from extreme environments represent a valuable source of novel bioactive secondary metabolites with potential antimicrobial applications. The aim of this study was to isolate, identify, and evaluate the antimicrobial potential of a newly isolated strain of actinobacteria. AHA8 strain, was isolated from an Algerian desert soil sample in the Ahaggar region (Tamanrasset) by the dilution-agar plating method using a chitin-vitamins B medium supplemented with nalidixic acid and actidione. Morphological characterization indicated that this strain belonged to the genus Streptomyces. Phylogenetic analysis based on the 16S rRNA gene showed that the strain is closely related to Streptomyces djakartensis NBRC 15409T (99.57% sequence similarity). Strain AHA8 showed very strong activity against pathogenic staphylococci, including Staphylococcus aureus (MRSA 639c), as well as against other Gram-positive bacteria: Bacillus subtilis (ATCC 663) and Listeria monocytogenes (ATCC 13932). Additionally, the strain exhibited a moderate activity against mycotoxigenic and phytopathogenic fungi, including Aspergillus carbonarius (M333), A. westerdijkiae (ATCC 3174), Fusarium culmorum (Fc), and Umbelopsis ramanniana (NRRL 1829). Almost the same results were observed for Gram-negative bacteria and the pathogenic yeast Candida albicans (M3). Therefore, four solvents (n-hexane, dichloromethane, ethyl acetate, and n-butanol) were used to extract the bioactive secondary metabolites produced by the AHA8 culture on a synthetic starch medium. The highest antibacterial activity was obtained with the butanolic and ethyl acetate extracts. These findings demonstrate that the desert-derived strain AHA8 represents a promising source of antimicrobial secondary metabolites and supports further studies aimed at the purification and characterization of its bioactive compounds.

Keywords: 16S RNA gene; Actinobacteria; Algerian Saharan soil; Antimicrobial activity; Streptomyces.
DOI: https://doi.org/10.61215/auofb.2026.2.03








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