In desert ecosystems, arthropods such as scorpions are understudied, and sufficient information is still lacking regarding their biodiversity. Specimen collection was carried out over 24 months (2016–2017). This study assessed the phenology, abundance, richness and diversity of scorpion species in arid ecosystems of the Sahara desert of Algeria (Ghardaïa). It examined the potential influence of climate parameters (precipitation, temperature and wind) on activity density, diversity and the phenological distribution of the species among seasons. We identified eight Buthidae species: Androctonus aeneas, Androctonus amoreuxi, Androctonus australis, Buthacus samiae, Buthacus spinatus, Buthacus elmenia, Buthus saharicus and Lissothus chaambi. Androctonus amoreuxi and Androctonus australis were the most abundant and omnipresent species, comprising 54.41% and 33.82% of all species found, respectively. Shannon’s index and the evenness index demonstrated a very poor diversity of scorpions in this region and a poor balance between the number of sampled species. Seasonal variation and climate parameters, i.e., temperature and wind, influenced the number, distribution, and the diversity of scorpions. The number of species found in Ghardaïa Province represent more than 20% of the scorpion species reported in Algeria.

The white-headed duck is a globally threatened species and its populations have become fragmented and undergone major decline in recent decades. Changes including long-term abundance (five times from 2005 to 2018) and diurnal activity budget (2010−2011 and 2017−2018) with respect to the effect of habitat features at Boussedra marsh (unprotected area) were compiled in order to fill some gaps in the status and trend of North African populations. The population size of the white-headed duck decreased over years from 2010 to 2018 by about 52.81%, and was positively associated with interior vegetation area, but not significantly with water surface area. Trends of population dynamics differed among seasons, and the number was higher in wintering than breeding season. Sleeping (44.93%, 23.74%) and feeding (59.09%, 27.43%) were the dominant diurnal activities at both the years of study, respectively. Boussedra marsh plays an important ecological role as a diurnal forging habitat and reproduction site for this threatened species and as a shelter for other waterfowl.

Decreased ambient temperature and shorter reproductive seasons are the two main obstacles that ectotherms face at higher elevations. Studies have shown that some life history traits such as phenological windows of activity, duration, and fitness components vary as elevation increases. However, studies on the elevational gradient at the southern range limit of species are lacking. In this study, we aim at assessing some aspects of the life history of a spider species, the sprassid Micrommata ligurina (C.L. Koch, 1845), across an elevational gradient from 30 to 1030 m in Northeast Algeria. There was strong evidence of an elevational shift in the phenology of reproduction with a delay rate of 2.2 days per 100 m of elevation, and the three quantiles of the phenology (10, 50, and 90%) shifted with the same magnitude across elevation. In all sites from low to high elevation, the species showed a decrease in number of individuals. The mean number of eggs was 200 ± 35 eggs, and the mean number of hatching eggs was 110.9 ± 23.5 eggs. The clutch size at high elevation sites was higher than that of low-elevation sites, but in contrast, the hatching success was higher at lower elevation sites. Overall, the species exhibited clear elevational clines in life history traits and abundance, suggesting a high potential of plasticity. This work constitutes the first study carried out on spider species ecology in the region.

The aim of this study is to examine the Odonata fauna structure and composition in Kabylia’s wetlands (central north Algeria) by sampling 36 potential sites (16 wadis and 20 water reservoirs) in the two main departments of this region, namely, the Kabylia of Djurdjura (Tizi Ouzou) and the Kabylia of Soummam (Bejaia). This region has one of the most important hydrographic systems in Algeria and a wide range of exceptional wetlands due to its important rainfall regime. A lack of studies, especially in the western part of the region (Tizi Ouzou), prompts a specific inventory and ecological analysis of the Odonata population over a period of 6 months (from April to September 2021). Forty species of Odonata have been recorded in Kabylia, of which Pyrrhosoma nymphula represents a new record for Algeria, raising the reference list to 64 species. There are four northern African endemic species and among these, we report on the rediscovery of the critically endangered (EN) Calopteryx exul in Algeria, recorded in the 19th century and deemed to have been extinct after an absence of more than a century; Gomphus lucasii is assessed as vulnerable (VU) and Enallagma deserti and Platycnemis subdilatata are judged as least concern (LC).

Context: Dams construction appears to have multi-dimensional effects on the river environment, and it especially affects the thermal condition of rivers. Aims: The objective of this work was to assess downstream thermal responses to the Charef Dam in relation to the water flow and the water residence time. Methods: During the year 2012, the hydrological parameters upstream and downstream of the dam were monitored. Key results: Salinity, electrical conductivity, total dissolved solids (TDS) and water flow all responded similarly, with larger magnitudes in waters upstream of the dam than downstream, whatever the season. In terms of flux, the Charef Dam retains 59 and 56% of the incoming water and TDS fluxes respectively. Furthermore, the upstream water temperature is higher than that of the downstream in 83% of samples. During the dry season, the thermal response of the waters downstream of the Charef Dam can exceed 2°C (downstream cooling). Conclusions: Despite being a small dam, the water residence time (2.3 years) in the Charef Dam has a significant effect on the downstream water temperature. Implications: These temperature changes may cause significant physicochemical and biological issues. Restoration practices such as increasing discharges during dry seasons and riparian cover restoration could mitigate thermal impacts and minimise negative effects.