Environmental drivers of macroinvertebrate communities in High Arctic rivers (Svalbard)

Summary The impacts of climate-induced environmental changes on freshwater biodiversity are not well understood in Arctic regions. We quantified water source contributions (meltwater, ground water), environmental habitat conditions and benthic macroinvertebrate community dynamics in north-west Svalbard. The aim was to use contemporary findings to infer how future environmental change may affect these Arctic river ecosystems. Water source dynamics played an important role in influencing environmental habitat conditions; meltwater contributions to flow were related significantly to discharge, channel stability, electrical conductivity and pH. Low regional benthic macroinvertebrate diversity relative to other Arctic regions was attributed to harsh winter conditions and biogeographical dispersal constraints associated with the Svalbard archipelago. Generalised estimating equations and multivariate ordination models showed benthic macroinvertebrate diversity and abundance were influenced significantly by several environmental habitat variables. Rivers in non-glacierised basins typically supported more diverse and abundant communities than those in glacierised basins, most likely as a consequence of the warmer water temperature and less-disturbed habitat conditions associated with these systems. Consequently, shifts in water source contributions driven by changes in climate may alter environmental habitat conditions in Svalbard rivers and could lead to an increase in abundance and diversity among some freshwater macroinvertebrate communities.