This study aimed to determine the impact of various pressures on the functional composition of OCH (Odonata, Coleoptera, and Heteroptera) in streams within the northwest Rif region of Morocco. We ...examined how OCH traits respond to human-induced pressures in selected stream sites in Morocco’s northwestern Rif region. OCH specimens were collected from 36 sites using a Surber sampler with dimension of 20 × 20 cm and mesh size of 500 µm over the course of two years, from 2021 to 2023. We measured physico-chemical and hydraulic parameters such as temperature, pH, DO, and NO-3. Sixty-seven trait attributes from 11 trait classes were assigned to the collected OCH taxa at the family level. Following the delineation of sites along the gradient of impacts in the study area, we categorized 7 sites as slightly impacted sites (SISs), 19 sites as moderately impacted sites (MISs), and 10 sites as heavily impacted sites (HISs). We successfully identified and categorized the traits as either vulnerable or tolerant based on RLQ models. Traits such as reproductive cycles per year and tegument respiration, which were positively correlated with SISs in the RLQ model and also positively correlated with depth and chlorine, were identified as vulnerable traits. Crawling locomotion and full water swimming were identified as tolerant traits. The distribution patterns of the OCH taxa revealed a robust correlation between the taxa and the sampling sites. Notably, taxa such as Nepidae, Naucoridae, and Corixidae exhibited widespread distribution and a strong association with the SISs. On the other hand, traits related to living macroinvertebrate food sources and reproduction in vegetation, specifically clutches, exhibited a negative correlation with total dissolved solids. Incorporating OCH functional traits into biomonitoring programs allows for a more comprehensive assessment of river ecosystems. This approach provides a nuanced understanding of how different stressors impact the community composition and overall ecological health.
The involvement of trait-based approaches is crucial for understanding spatial patterns, energy flow and matter transfer in running water systems, which requires consistent knowledge of the ...functional structures of aquatic communities, with the advantage of combining physical properties and behavioral mechanisms of food acquisition rather than the taxonomic group. The present study indicated how functional feeding groups may be used as a proxy for classical taxonomic evaluation, as well as the potential interest in incorporating them as indicators of anthropogenic stressors. The composition and abundance of the functional feeding groups of aquatic insects were examined from September 2021 to August 2022 along the Western Rif Region. Benthic samples were collected from nine sampling points in the studied area using a Surber sampler with a mesh size of 500 µm and a diameter of 20*20 cm. The stations included in this work were chosen for their accessibility as well as their position on the hydrographic systems. The abundance of sampled aquatic organisms in the whole study area revealed 5,342 individuals belonging to 60 families and seven orders of aquatic insects, classified into five feeding functional groups. In terms of abundance, Collector-gatherers (Ephemeroptera and Diptera) were the most abundant trophic group at most of the sites, with a proportion of 38.47%. Predators (Coleoptera, Hemiptera and Odonata) were the second group at all sites, followed by Collector-filters, accounting for 39.53%, 28.14% and 22.37% respectively, while Scarpers and Shredders had the lowest representation across all sites with 4.16%. The high number of registered Collectors could be related to their ability to feed on a diverse range of food items compared to the remaining trophic guilds. According to the Canonical Correspondence Analysis results, physicochemical (i.e. T, pH, BOD
, Cl- and NO
-) and hydromorphological (i.e. current velocity and depth) variables were amongst the key predictors of shaping the functional structure of aquatic biota during this investigation. It is highly recommended to carry out suitable measures to largely attenuate anthropogenic pressures in order to preserve the integrity of freshwater bodies and their biota.
Spatial pattern comprehension, dynamism of energy, and transfer of matter in running freshwater systems are significant for the functional composition of aquatic communities. Recently, the ...trait-based approach has become the center of functional assessment. The trait-based approach can complement structural bioassessment tools and has the advantage of combining ecological features and biological characteristics rather than only the use of a taxonomic-based approach. In the current study, we explored the differential responses of EPT (Ephemeroptera, Plecoptera, and Trichoptera) traits in selected stream sites in the northwestern Rif of Morocco. A Surber sampler with a 500-µm mesh size and dimensions of 20 × 20 cm was used to collect EPT samples at the sites. Physicochemical and hydromorphological parameters, including temperature, pH, BOD
5
, NO
-3
, Cl
−
, depth, and current velocity, were used to characterize the water quality of the sampled sites. We used 54 trait modalities belonging to 11 trait classes to describe the collected EPT at the family level. We conducted RLQ model and fourth-corner test to examine the interaction between the EPT traits assemblage and habitat predictors at the 36 sampled sites along the stretch of the study area. The RLQ ordination revealed that the distribution patterns of EPT traits differed significantly over the 36 sites. Thus, we expected that the EPT traits assemblage would reflect the degree of the detected environmental pressures. The RLQ model indicated that elevated nutrient levels and conductivity were the key factors explaining most of the variability in functional traits at the downstream sampled sites. EPT traits such as life cycle duration, food preferences, maximal potential size, and substrate preference were positively associated with sites exhibiting notable deterioration. Baetidae and Leptophlebidae in S2, S3, and S20 favored these trait assemblages. The fourth-corner test revealed that there was no statistically significant difference in the relationship between the EPT traits and selected physicochemical and hydromorphological parameters.
We describe a new species of the genus Calamoceras which currently has only two species: Calamoceras illiesi Malicky & Kumanski 1974 and Calamoceras marsupus Brauer 1865. We also discuss its ecology ...by analyzing some biophysical parameters. The larva and the adult of this new species, Calamoceras riffensis sp. nov. have been found by specialists from the Rif region in northwestern Morocco since 1998. All the specimens collected differ from the two known species by conspicuous morphological differences.
