Ecological Influence of Organic Pollution on the Distribution of Benthic Macroinvertebrates in Some Control Forest Watercourses in Cameroon

Monitoring of water quality and distribution of some benthic macroinvertebrates was carried out in a few control watercourses in the Mefou watershed, from August 2022 to June 2023 with the aim of identifying some ecological factors that influence the distribution of benthic organisms in forest areas. The evaluation of granulometric and physicochemical quality was carried out following the appropriate methods and the collection of benthic organisms following the multihabitat approach. The analysis of the particle size parameters shows that the coarse fraction dominates all the points explored, although the beginning of siltation was observed in the middle part of the Abouda and Fam rivers. Physico-chemical analyses revealed a relatively stable environment with well-oxygenated water, low values of organic pollution indicator parameters and low and constant temperatures throughout the watersheds. The analysis of the biological structure shows a total of 8483 individuals collected, all belonging to the arthropod phylum and the insect class. From the orders obtained, Hemiptera dominate the benthic fauna with 6 identified families. The organisational structure of the benthic community was analysed through the calculation of diversity and fairness indices and allows us to affirm that the benthic macroinvertebrate community is diverse and well organised.&nbsp

Semi-aquatic Epilamprinae cockroaches (Blattodea: Blaberidae) in Cameroon: towards a revision of continental African species of Rhabdoblatta Kirby, 1903 and Africalolampra Roth, 1995

Although semi-aquatic cockroaches have been known for a long time, these insects remain little studied and their diversity underestimated. While a few species are known from Asia or South America, only a single one is known to be associated with water in Africa. Here, we report two species of semi-aquatic cockroaches of the subfamily Epilamprinae from Cameroon. One of these species is new: Rhabdoblatta fotoi Nyame Mbia, Legendre & Biram à Ngon sp. nov. Africalolampra camerunensis (Borg, 1902) comb. nov. was also found associated to these streams and we provide an extended description of this species, as well as for Africalolampra stipata comb. nov., also known from streams in West Africa. Another species was found in Cameroonian streams and is described here, although only identified at the family level (Blattellidae). The descriptions are based on morpho-anatomic characters, including male genitalia. Because nymphs were found primarily associated with water – more than adults – we provide a description of nymphs whenever possible. We provide molecular data (12S rRNA marker) for two of these water-associated species that we compared with published and unpublished sequences of Epilamprinae in a Maximum Likelihood approach. We also illustrate all but one species from continental Africa in the genera Africalolampra and Rhabdoblatta, including R. punctipennis (Saussure, 1895) which we reinstate. We provide a map and list of localities for Africalolampra and Rhabdoblatta spp. from continental Africa and Madagascar, as well as an identification key for species of Africalolampra. We finally discuss putative adaptations of semi-aquatic cockroaches

Impact of the anthropogenic activities on the diversity and structure of benthic macroinvertebrates in tropical forest stream

The diversity and structure of benthic macroinvertebrates related to some physico-chemical parameters were studied in the Konglo stream, an affluent of the Nyong river in Cameroon. The benthic macroinvertebrates were collected at three stations according to multihabitat the approach and physic-chemical parameters were sampled and analyzed using classic methods between February 2014 and August 2014. During this study, 1969 individuals belonging to 3 phyla, 7 classes, 16 orders, 63 families and more than 90 genera were sampled. The class of Insects, including 9 orders, 54 families and more than 79 genera, predominates with 74.81 % of the relative abundance, followed by the class of Decapods regrouping 21.94 % of the individuals distributed in 1 order, 2 families and 2 genera, however less varied. The other classes (Achaeta, Oligochaeta, Bivalvia, Gastropoda and Arachnida) represent only 3.25 % of relative abundance. The spatial variation of taxonomical richness shows a decrease of the diversity from upstream to downstream as well as the Ephemeroptera-Plecoptera-Trichoptera (EPT) index. Moreover, the Sörensen similarity index indicates dissimilarity between the station K3 and the two others stations. Otherwise, the rank-frequency diagram of Frontier and the Shannon and Weaver index show that the structure of benthic macroinvertebrates is in ecological starting succession in upstream and middle while it is closed to ageing in downstream

Water Quality And Benthic Macroinvertebrates Of Tropical Forest Stream In South-West Region, Cameroon

A study was carried out in Ndongo stream, located in Buea, from May to October 2017, to assess the water quality and evaluate the structure of benthic macroinvertebrates. Physicochemical analysis showed that water from Ndongo was well oxygenated (82.21 ± 6.59 %), slightly acidic (pH=6.82 ± 0.22 UC) and alkaline with low quantities of nitrogen compound (2.9 ± 3.57 mg/L NO3+; 0.02 ± 0.02 mg/L NO2– and 0.89 ± 1.78 mg/L NH4+). Regarding the biology of macroinvertebrates, a total of 2058 individuals were collected and identified into 4 phyla, 5 classes, 11 orders, 32 families and belonging to 44 genera. The Shannon & Weaver and Pielou evenness reveal that the benthic macroinvertebrates were more diversified in upstream

Distribution Profile of Benthic Macroinvertebrates in Some Rivers of Yaoundé City and Its Surroundings Using Self Organizing Map and Indicator value methods

Urban sprawl leads to the degradation of aquatic environments and, consequently, to the destruction of biodiversity. With the aim of highlighting the distribution profile of benthic macroinvertebrates in the city of Yaoundé and its surroundings according to the level of degradation, this study was carried out in seven rivers. A total of 144 taxa of benthic macroinvertebrates, belonging to 74 families, 15 orders, five classes, and three phyla, were collected from seven rivers in urban, peri-urban, and forest environments on Yaoundé and its surroundings. The self-organizing map (SOM) analysis tool was used to group the collected taxa from all stations into three clusters or affinity cores. The indicator value analysis (IndVal) method was employed to determine, based on their ecological preferences, which organisms were most likely to belong to each group. Out of the 144 collected taxa, only 44 were indicated to represent the three different groups. Thus, three communities were defined: the Hydropsyche community, with Hydropsyche sp. as the predominant taxon in Group III, characterizing well-oxygenated and low-mineralized stations; the Hydrocyrius community, where the species Hydrocyrius sp. predominates in Group I, describing stations with low oxygenation and moderate mineralization; and the Lumbriculidae community, where Lumbriculidae is the taxon associated with environments with high mineralization and critical oxygenation. These two methods contribute to the biomonitoring of tropical aquatic environments, firstly by grouping organisms by affinity and then identifying those that reflect the environment conditions. This facilitates the detection of changes in the quality of hydrosystems and guides management and conservation efforts