Distribution and habitat preference of Ephemeroptera and Trichoptera in subtropical mountain streams: implications for monitoring and conservation.

Romina E Principe,Javier A Márquez,Luciana Cibils-Martina

doi:10.1590/0001-3765201920180692

Romina E Principe, Javier A Márquez + Show 1 more

Open Access

https://doi.org/10.1590/0001-3765201920180692

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Abstract

The assessment of biotic-habitat relationships provides key information to predict biotic responses to perturbations and important tools for river management and monitoring. This study aimed to assess the spatial distribution of Ephemeroptera and Trichoptera in mountain streams of central Argentina. We evaluated the effect of seasonality and identified the variables conditioning the abundance of the assemblages and the habitat with the highest taxonomic richness. Sampling was carried out in four streams (Carcarañá River basin) during high and low water periods. Three lotic habitats were sampled: riffles, coarse substrate runs, and fine substrate runs; and physicochemical and habitat variables were measured. We found differences in assemblage composition, among the 25 genera of Ephemeroptera and Trichoptera, at the habitat level. The most important variables affecting distribution patterns were substrate and flow type, but macroalgae and organic matter (twigs, leaves, and detritus) were also important predictors. Riffles maintained the highest richness but when considering only the Ephemeroptera taxa, fine substrate runs emerged also as an important habitat for these taxa. Our study provided valuable ecological information related to habitat preference of taxa with a key role in stream functioning and of great usefulness for the monitoring of lotic systems.

Highlights

The distribution of aquatic insects can be explained as the interaction between hydrogeological conditions and life history of organisms (Statzner et al 1997, Floury et al 2017)
Current velocity varied among the different habitat types (Table I) showing the highest mean value in riffles during the high water period (0.64 m.s-1) and the lowest value in fine substrate runs during the low water period (0.22 m.s-1)
In coarse substrate runs flow type was rippled in all cases and fine substrate runs presented rippled and smooth surface flow

Summary

Introduction

The distribution of aquatic insects can be explained as the interaction between hydrogeological conditions and life history of organisms (Statzner et al 1997, Floury et al 2017). Distribution patterns of aquatic species strongly depend on changes in hydro-geomorphological conditions operated at different temporal and spatial scales (Mykrä et al 2007). Several of these changes are produced by human activities which modify stream conditions and alter lotic habitats affecting the aquatic biota (Allan and Castillo 2007). Some of the most sensitive species to disturbances are within the EPT taxonomic group (Ephemeroptera, Plecoptera and Trichoptera) (Resh et al 1995, Cortes et al 2013). The EPT group is often dominant and highly frequent in many lotic systems (Wiggins 1996, Barber-James et al 2008) and it has an important role in organic matter breakdown and in the transference of matter and energy in food webs (Hauer and Resh 2017) having, a key role in the functioning of riverine systems

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