Abstract
Biological invasions are a global trend due to globalization of the world. An important goal of invasion biology is to identify environmental characteristics that may make a region receptive to invasions. We tested the hypothesis that environmental variables have stronger effect on the biomass of the alienCercopagis pengoiin the Neva Estuary than biotic interactions with other zooplankton species. Hierarchical cluster, principal component and Pearson correlation analyzes were used to elucidate changes within the zooplankton community along environmental gradients. The data analysis showed that the biomass ofC. pengoiwas higher in waters with higher salinity, low temperature, high transparency, lower chlorophyllaconcentration and lower proportion of chlorophyll in particulate suspended matter. The biomass ofC. pengoishowed significant positive correlations with biomasses of its potential preys. However, we did not find direct significant negative correlations betweenC. pengoiand larger zooplankton predatorsLeptodora kindtiiandBythotrephesspp. This research generally supports the hypothesis that if environmental variables are appropriate for an exotic species, then that species is likely to invade successfully, regardless of the native species already present.
Highlights
Biological invasions are a global trend due to globalization and increased traffic between different countries (Cohen and Carlton, 1998; Dirzo et al, 2014)
This research generally supports the hypothesis that if environmental variables are appropriate for an exotic species, that species is likely to invade successfully, regardless of the native species already present
In its natural habitat in the Northern Caspian Sea, C. pengoi prefers coastal water areas and bays, where the depth does not exceed 75 m and the salinity reaches 10 PSU; it is tolerant to temperature and disappears from plankton only when the water temperature drops below 10◦C (Mordukhai-Boltovskoi and Rivier, 1971)
Summary
Biological invasions are a global trend due to globalization and increased traffic between different countries (Cohen and Carlton, 1998; Dirzo et al, 2014). The introduction of non-indigenous species (NIS) into ecosystems can lead to the displacement of native species and other negative consequences. Some non-indigenious species may have economic consequences on fisheries and the tourism industry, and can result in substantial monetary costs and/or alterations to entire ecosystems and social systems (Kumschick et al, 2012, 2015; Galil et al, 2014; Ojaveer et al, 2015). One of such species is Cercopagis pengoi. This planktonic crustacean is an important prey for fish, especially for Baltic herring (e.g., Antsulevich and Välipakka, 2000), while simultaneously appearing to compete with fish for food sources (Gorokhova et al, 2005)
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