Diverging life cycle patterns of two Diamesa species (Diptera, Chironomidae) in High Arctic streams, Svalbard

Stefan Andreas Schütz,Leopold Füreder,John E. Brittain

doi:10.1007/s00300-021-02987-1

Stefan Andreas Schütz, Leopold Füreder + Show 1 more

Open Access

https://doi.org/10.1007/s00300-021-02987-1

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Abstract

The fauna of streams in the High Arctic, dominated by chironomids, is shaped by extreme environmental conditions that represent the physiological limits for benthic invertebrates. Despite their ecological importance, little is known of chironomid life histories, development strategies and the key abiotic drivers limiting larval growth in High Arctic streams. We investigated the larval development and growth in three High Arctic rivers with contrasting water sources, thermal regimes and nutrient characteristics. Populations of the larvae of Diamesa bohemani (Goetghebuer 1932) and Diamesa aberrata (Lundbeck 1898) from two sampling occasions in July and August 2016 were morphometrically analysed to determine life history patterns and instream productivity. Water temperature differences lead to diverging development patterns on local spatial scales. The lowest larval growth was in a groundwater/snowmelt fed stream with low food concentration and quality, suggesting that stream productivity is not primarily water source dependant, but is dependent on the nutrient supply. Glacially influenced streams are clearly more productive than previously assumed, resulting in comparable secondary production to groundwater/snowmelt-fed streams.

Highlights

Streams in the High Arctic are situated in one of the most extreme climatic regions (e.g. Blaen et al 2014)
In this study we studied the influence of water temperature and nutrient availability on the life history and larval growth of key chironomid species in the High Arctic
We found variations in life history patterns, growth rates and larval weight of two chironomid species in three High Arctic streams that considerably varied in terms of water source, water temperature and food quantity and quality

Summary

Introduction

Streams in the High Arctic are situated in one of the most extreme climatic regions (e.g. Blaen et al 2014). Larvae of cold-stenotherm Diamesa species can locally reach high densities and thereby significantly contribute to the otherwise short food chains of such harsh ecosystems (see Robinson et al 2014; Niedrist and Füreder 2017 for alpine streams). Despite their small body size, chironomid larvae play an essential role in the self-purification of the water bodies, feeding on autochthonous and allochthonous organic matter and simultaneously representing a key food source for fish Chironomids are an essential link in the aquatic and terrestric food chain of High Arctic ecosystems

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