Abstract
The marbled crayfish (Procambarus virginalis) is an invasive freshwater species spreading across Europe. Understanding its establishment and distribution is crucial, particularly in relation to temperature. This study examined the role of water temperature in marbled crayfish invasion in a warm outflow channel of a power plant in Estonia. We hypothesized that warmer water temperatures and the temperature gradient along the channel would influence crayfish establishment, distribution, and trophic niche. Temperature loggers revealed a distinct gradient, with the channel being warmer than the adjacent reservoir, providing a more suitable habitat for crayfish. Stable isotope analysis (13C and 15N) with MixSIAR and SIBER models showed distinct trophic niches along the channel: crayfish at the head of the channel consumed macroinvertebrates and macrophytes, while those at the mouth mainly consumed macroinvertebrates and periphyton. Additionally, crayfish shifted from eating primary consumers in spring and summer to primary producers in autumn. Water temperature was a key factor in crayfish establishment, but food availability also likely influenced their distribution. This study highlights the role of water temperature and ecological factors in the invasion dynamics of marbled crayfish, especially in the context of global warming.
Keywords: Stable isotopes • trophic niche • invasive species • population dynamic • temperature effect
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