Biometrics analysis of the stem fibers of some local Algerian plant species

Studying the biometric characteristics of the stems of plant species has been of great interest to researchers in the wood and paper industry. The use of plant fibers has been widespread in the fields of composites, buildings, insulation, plastics and automobiles. The present study aimed to investigate the biometric characteristics of the stem fibers of local Algerian plant species, viz. Group 1 (Lygeum spartum and Stipa tenacissima), Group 2 (Linum usitatissimum in the greenhouse and Linum usitatissimum in natural conditions), Group 3 (Retama monosperma and Retama raetam) and Group 4 (Phoenix dactylifera and Ricinus communis). The extraction process was carried out using 1 M NaOH at 60 °C for 48 hours, and the fiber length was calculated for all the species using a micrometer. The fiber length of stems of all the species ranged from 0.36 to 5.18 mm. Then, the difference between each of the two species was approximated using Student's test. The results obtained showed that the t value ranged from 0.50 to 1.79 for Groups 4 and 1, respectively. There was no significant difference between them. These results suggest that these species are promising raw materials for paper production due to their adequate fibre length

Effects of anthropogenic factors on spider communities (Arthropoda: Araneae) in Chréa National park (Blida, Algeria)

Chrea National Park, one of the 11 national parks in Algeria, is natural and diverse but under different pressures: urbanisation, fires caused by the high flux of visitors. Several ecological and systematic studies have been conducted on the Araneae, the most important epigeal fauna, but no attention was given to the anthropogenic parcels of the Park. To assess the effects of urbanisation and fires on the ecology of this fauna, spiders were collected monthly for 2 years, using 'Pitfall' traps in three disturbed stations: burned, urbanised and reforested and three natural sites as control. In total, 1,476 specimens were sampled (19 families, 42 genera and 68 species). Zodarion algericum was the dominant species (13.25%), particularly in the burned station. Mann-Whitney U test showed a significant difference between urbanised and nonurbanised sites in contrast to other ones and no significant differences with the control. Our results show that fires transform the forest into a mosaic of habitats, with open gaps of different stages of succession. In addition, the reforestation of cedars without any agricultural practices has no negative effects on the Park. No loss of biodiversity was observed; this would encourage the restoration of the forest to protect its fauna and flora