Microhabitat preferences of fish assemblages in the Udzungwa Mountains (Eastern Africa)

Abstract

Environmental flow assessment (EFA) involving microhabitat preference models is a common approach to set ecologically friendly flow regimes in territories with ongoing or planned projects to develop river basins, such as many rivers of Eastern Africa. However, habitat requirements of many African fish species are poorly studied, which may impair EFAs. This study investigated habitat preferences of fish assemblages, based on species presence–absence data from 300 microhabitats collected in two tributaries of the Kilombero River (Tanzania), aiming to disentangle differences in habitat preferences of African species at two levels: assemblage (i.e. between tributaries) and species (i.e. species‐specific habitat preferences). Overall, flow velocity, which implies coarser substrates and shallower microhabitats, emerged as the most important driver responsible of the changes in stream‐dwelling assemblages at the microhabitat scale. At the assemblage level, we identified two important groups of species according to habitat preferences: (a) cover‐orientated and limnophilic species, including Barbus spp., Mormyridae and Chiloglanis deckenii, and (b) rheophilic species, including Labeo cylindricus, Amphilius uranoscopus and Parakneria spekii. Rheophilic species preferred boulders, fast flow velocity and deeper microhabitats. At the species level, we identified species‐specific habitat preferences. For instance, Barbus spp. preferred low flow velocity shallow depth and fine‐to‐medium substratum, whereas L. cylindricus and P. spekii mainly selected shallow microhabitats with coarse substrata. Knowledge of habitat preferences of these assemblages and species should enhance the implementation of ongoing and future EFA studies of the region.

Low diversity of fishes in high elevation Afrotromontane streams renders them unsuitable for biomonitoring

“…Small‐bodied Enteromius and Clarias spp. are rhithronic species with preferences for cover and limnophilic features (Fugère, Mehner, et al, 2018; Harniman et al, 2013; Muñoz‐Mas et al, 2019). The longitudinal distribution of fishes in the Sondu‐Miriu River is also influenced by the Odino Waterfalls, which prevent the upstream migration of fishes.…”

“…Small-bodied Enteromius and Clarias spp. are rhithronic species with preferences for cover and limnophilic features (Fugère, Mehner, et al, 2018;Harniman et al, 2013;Muñoz-Mas et al, 2019).…”

Conserving Rivers and Their Biodiversity in Tanzania

“…Environmental flow assessment studies (see Table 1 and subsection below) have included snapshot sampling for fishes and macro-invertebrates, providing additional data and in some cases the first field sampling campaigns for Tanzanian rivers [24][25][26][27][28][29]. For example, an initial environmental flow assessment in the Wami River basin identified five different sites where field sampling was conducted during both dry and wet seasons in 2007, including sampling of riparian biota, macroinvertebrates and fishes.…”

Not a galaxy far, far away. A first look into the microhabitat of Romanogobio skywalkeri

“…Main factors that define abundance and species arrangement are water depth, flow‐velocity, and substrate composition (Akbaripasand & Closs, 2018; Allan, 1995; Mallet et al, 2000; Vadas & Orth, 2001). Also riparian vegetation, cover, and introduced species have been found to influence habitat use (Allouche, 2002; Muñoz‐Mas et al, 2019; Sowersby et al, 2016). Microhabitats are usually based on point measurements that describe the local environmental conditions and are mostly influenced by the local hydraulic conditions (Hauer et al, 2007).…”