Climate extreme triggers cold-water community rescue

Context Mountain-top associated instream fauna with restricted ranges and limited dispersal capability are especially vulnerable to extinction under global warming and climate extremes. Aims Rescue and housing of multiple cold-water taxa on short timelines in reaction to extreme drought. Methods We undertook multi-species rescue (fishes: Gadopsis marmorata, n = 50; Galaxias olidus, n = 150; and a crayfish Euastacus sulcatus, n = 50) from the headwaters of the Condamine–Balonne catchment, temporarily holding animals in small (200 L) and large (1000 L) aquaria in single- and mixed-species contexts, at below 23°C. Key results Galaxias olidus was successfully kept in one of the small aquaria, but did not survive in mixed-species aquaria, partly being due to predation by other species. Euastacus sulcatus showed decreased survivorship at moulting (predation). Large Gadopsis marmorata (>100-mm total length, TL) was aggressive, whereas maintaining smaller individuals and using large aquaria served to dampen overall aggression levels. Conclusions Holding mixed taxa following field rescues requires attention to detail, including developmental-stage combinations within and across species, enclosure volume and availability of structure. Implications The simultaneous rescue of multiple co-occurring endemic taxa represents a promising aspect of research and adaptive management in the era of global climate change.