Climate‐driven range retraction of an Arctic freshwater crustacean

Abstract

Summary 1. Species responses to global warming are predicted to be manifest as poleward and upward extension of species ranges, whereas cold‐adapted species experience range retractions. We report on recent range retraction of a freshwater crustacean, the Arctic fairy shrimp Branchinecta paludosa (Branchiopoda, Anostraca) from alpine ponds of southern Norway, a southernmost extension of its otherwise arctic range. 2. The species was mapped during two separate surveys, in 1970 and 2011. In 1970, it occurred in numerous ponds from the tree line at 900 m altitude to high alpine sites at 1500 m. Re‐sampling of the same ponds 41 years later revealed extinction of populations from ponds along the lowest 200 m of its altitudinal range. 3. Reconstruction of summer temperatures for the periods 1965–70 and 2005–10 revealed a thermal increase for the period, corresponding to a c. 200‐m upward shift of the local isotherms. More specifically, the number of warm summer days had doubled in the lowest 200 m of the region, which might be particularly detrimental for the species. 4. The extinctions at lower altitudes were not compensated for by corresponding upward colonisations. The range retraction of B. paludosa is possibly associated with oxygen stress and hypoxia, induced by increased water temperatures.

Morphologically Conservative but Physiologically Diverse: The Mode of Stasis in Anostraca (Crustacea: Branchiopoda)

“…2). The extreme rarity of coexistence between fairy shrimps and fish is consistent with this pattern, as are the detrimental effects of fish stocking on fairy shrimp populations (Eriksen and Belk 1999; Lindholm et al 2012). Anostracan only survived in small, isolated habitats with peculiar features, and devoid of fish: shallow ponds and ephemeral pools, predominantly in inhospitable and extreme environments.

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Water browning mediates predatory decimation of the Arctic fairy shrimp Branchinecta paludosa

“…The fieldwork was conducted during 2014 and 2015 in the high alpine area of Dovrefjell in southern Norway, where B. paludosa is common in fishless ponds and lakes above the tree line, and where certain ponds also contains C. nyblaei . A previous survey of 121 ponds in the region had revealed a conspicuous loss of populations of B. paludosa at lower altitudes over the past four decades (Lindholm et al ., ). Eight of these ponds, four where the two species coexisted and four which only had B. paludosa (hereafter ‘ Branchinecta ponds’) were assessed in the present study.…”

“…One such potentially vulnerable species is the Arctic fairy shrimp Branchinecta paludosa (Branchiopoda, Anostraca), which inhabits fishless ponds and lakes in certain alpine regions of northern Europe. Extinction of this species has been observed across its lower altitudinal range during the last decades, in close correlation with increased summer temperatures (Lindholm et al ., , ). Nevertheless, its regional disappearance is not necessarily driven directly by temperature, but could rather be associated with secondary ecosystem responses, such as water browning and consequent alteration of predation regimes.…”

Environmental Impacts—Lake Ecosystems

“…Changes in distribution and diversity have already been observed in some freshwater groups, such as odonates in the UK (Hickling et al 2005). Other diversity shifts caused by local, climate-related range retractions have been reported for fishes in Iceland (Jeppesen et al 2010b) and crustaceans in Norway (Lindholm et al 2012). Correspondingly, analyses of long-term monitoring data on community composition revealed shifts in macroinvertebrate assemblages associated with ambient temperatures in Greenland, Iceland, Norway, Denmark and Sweden (Burgmer et al 2007;Friberg et al 2013).…”