Diversity, distribution and habitat requirements of aquatic insect communities in tropical mountain streams (South-eastern Guinea, West Africa)

Abstract

Considering that knowledge of the biodiversity of a region is the first step toward its conservation and given the paucity of studies on aquatic insects from the Simandou streams, the diversity of these communities was assessed. Aquatic insects were sampled with a hand-net (mesh size: 250 mm) on four occasions between March 2011 and September 2012 at 27 sites. Environmental variables were also recorded. Overall, 129 taxa belonging to 51 families and eight orders were recorded. Multivariate analyses gathered sites into three clusters in regard to aquatic insect composition. The rarefied taxonomic richness showed decreases in association with increasing levels of human impact. Cluster 1 that contained most disturbed sites displayed low taxonomic richness compared with the two others. The highest taxonomic richness was registered in cluster 2 that contained a mixture of upland and lowland sites; the latter remained minimally disturbed. These sites could be considered as reference sites in studies for assessing water quality. Generalised additive models calculated for the most frequent taxa showed that water temperature, dissolved oxygen, conductivity and pH were the incorporated explanatory variables. Therefore, further anthropogenic activities should preserve the surrounding forest in order to preserve the quality of Simandou streams and consequently aquatic biodiversity.Key words: West Africa / mountain streams / generalized additive models / taxonomic diversity / aquatic insects for the apparent popularity of these communities as bioindicators are that they are ubiquitous, species-rich and long-lived. Given their ability to integrate temporal conditions, they provide evidence of environmental conditions over long periods of time (Imoobe and Ohiozebau, 2009).

Composition and Structure of Aquatic Macroinvertebrate Communities in Mining Areas Streams (Côte d’Ivoire, West Africa)

“…Aquatic macroinvertebrates structure was described through taxonomic composition, rarefied richness, Shannon-Weiner index, Pielou's Evenness index, frequency of occurrence and Trichoptera, Plecoptera and Ephemeroptera index (EPT). Taxa richness was rarefied to eliminate any bias related to differences in abundances between samples (Heck et al, 1975;Edia et al, 2016). Calculations were performed using the lowest abundance (11 individuals for this study) found in all stations as the target number of individuals (Oksanen et al, 2013).…”

Aquatic insect communities in headwater streams of Ciliwung River watershed, West Java, Indonesia

“…Furthermore, a higher proportion of freshwater species are threatened with extinction than their terrestrial counterparts (Dudgeon 2010). Therefore, deterioration of aquatic biodiversity has become one of the main concerns in recent conservational and ecological studies in various parts of the world (Che Braun et al 2014;Edia et al 2016;Hill et al 2016;Principe et al 2019).…”

“…Furthermore, headwater streams offer vital services to humankind, namely the storage, regulation, and purification of water (Bucker et al 2010). All these services depend on healthy ecosystems that are currently endangered by degradation (Edia et al 2016). Although, headwater streams may be small in size, they provide habitats for a rich array of species, which enhances the biological diversity of the entire river system (Meyer et al 2007).…”

“…Furthermore, the catchment area of this river is originated from the slope of Gede-Pangrango Mountain (3000 m above sea level) of West Java. Taking into account that biodiversity knowledge of a region is the first step toward its conservation (Edia et al 2016) and given the paucity of studies on aquatic insects from streams and rivers in Indonesia, this study aims to assess and compare aquatic insect biodiversity and community structure in various headwater streams with different land use patterns (forest, tea plantation, village). Therefore, the results are expected to provide baseline information on which to build suggestions to advance the conservation efforts.…”

Diversité et Structure du Peuplement Ichtyologique du Bassin Inférieur du Fleuve Comoé (Côte d’Ivoire)

“…La richesse en taxons a été raréfiée pour éviter tout biais lié aux différences d'abondance entre les échantillons (Paillex et al, 2007 ;Edia et al, 2016). Dans la présente étude, la raréfaction a été appliquée à la richesse taxonomique par échantillon en utilisant la plus faible abondance (237 individus) enregistrée dans les échantillons comme nombre cible d'individus (Okasanen et al, 2013 L'indice de similarité de Jaccard, (1908) a été utilisé pour comparer les sites deux à deux, car il évalue la ressemblance entre deux relevés en faisant le rapport entre les espèces communes aux deux relevés et celles propres à chaque relevé.…”