Differences in stress tolerance and brood size between a non-indigenous and an indigenous gammarid in the northern Baltic Sea

Abstract

Differences in stress tolerance and reproductive traits may drive the competitive hierarchy between nonindigenous and indigenous species and turn the former ones into successful invaders. In the northern Baltic Sea, the non-indigenous Gammarus tigrinus is a recent invader of littoral ecosystems and now occupies comparable ecological niches as the indigenous G. zaddachi. In laboratory experiments on specimens collected between June and August 2009 around Tvärminne in southern Finland (59°50 0 N/23°15 0 E), the tolerances towards heat stress and hypoxia were determined for the two species using lethal time, LT 50 , as response variable. The brood size of the two species was also studied and some observations were made on maturation of juveniles. Gammarus tigrinus was more resistant to hypoxia and survived at higher temperatures than G. zaddachi. Brood size was also greater in G. tigrinus than in G. zaddachi and G. tigrinus matured at a smaller size and earlier than G. zaddachi. Hence, there are clear competitive advantages for the non-indigenous G. tigrinus compared to the indigenous G. zaddachi, and these may be further strengthened through ongoing environmental changes related to increased eutrophication and a warming climate in the Baltic Sea region.

Thermal limits in native and alien freshwater peracarid Crustacea: The role of habitat use and oxygen limitation

“…In fact, the alien D. villosus was one of the most heat‐sensitive species, confirming the results by Maazouzi, Piscart, Legier, and Hervant () who also observed greater heat tolerance in the native G. pulex than in D. villosus . However, this pattern contrasts those of other studies on crustaceans (Kenna, Fincham, Dunn, Brown, & Hassall, ; Sareyka et al., ) and ectotherms more generally (Bates et al., ; Lenz et al., ; Verbrugge, Schipper, Huijbregts, Van der Velde, & Leuven, ). If we investigate more species, this result could change, but at the very least, it suggests that classifying species based on their origin (native or alien) to derive the taxa vulnerability to global warming or to predict invasion success should be done with caution.…”

“…Sareyka et al. () compared two amphipod species and reported greater hypoxia tolerance in the most heat‐tolerant species. In addition, to respiratory responses when subject to hypoxia, differences between species in their thermal sensitivity of oxygen demand, expressed as Ea values, may explain their thermal tolerance.…”

Interactive effects of temperature and salinity on shell formation and general condition in Baltic Sea Mytilus edulis and Arctica islandica

“…How severely organisms are impacted by warming and de salination will also depend substantially on the responses of interacting species and concurrent shifts in biotic interactions. These interactions must be investigated before sound predictions can be made about future distribution limits (Sareyka et al 2011). …”

Impacts of changing climate on the non-indigenous invertebrates in the northern Baltic Sea by end of the twenty-first century

“…In Europe all of the Ponto-Caspian species, except for E. warpachowskyi, have successfully inhabited many polluted rivers with high ionic content (Grabowski et al 2009;Kestrup and Ricciardi 2009;Wijnhoven et al 2003). Adults of G. tigrinus survive temperatures from near zero up to 32.2-34.2°C (Sareyka et al 2011;Wijnhoven et al 2003) but laboratory exams indicate that the species is not able to reproduce in temperatures below 5°C (Pinkster et al 1977). The PontoCaspian amphipods have a generally wide temperature Table S1 tolerance with their lower occurrence limit ranging from 2-11.3°C to upper limit 24-30°C (Table S1).…”