Climate warming and the agonistic behaviour of invasive crayfishes in Europe

Abstract

International audienceClimate warming often leads to shifts in the strength and sign of agonistic interactions among species, which in turn may change their distribution ranges. Notwithstanding the ubiquity of this phenomenon, there is scant literature about how interspecific agonistic behaviour changes with altered thermal regime, especially for invasive species such as three widespread North American crayfishes in Europe (Orconectes limosus, Procambarus clarkii and Pacifastacus leniusculus). * We conducted a laboratory study to analyse some descriptors of agonistic behaviour in fighting dyads of similarly sized males of the three species' combinations, both at 20 °C (the current maximum water temperature in the study area, central France) and 27 °C (the maximum expected in the next 80 years under the more pessimistic IPCC greenhouse gas emission scenario). * The results showed significantly different responses to warming by the three crayfishes. At 27 °C, O. limosus spent more time motionless and P. leniusculus was more often the subordinate, independent of the opponent. On the contrary, the agonistic strategy of P. clarkii did not change with temperature: when engaged in fighting, this species outcompeted both O. limosus and P. leniusculus. * Caution should be taken when extrapolating laboratory studies to the field, but these results, combined with outputs of previous modelling exercises, suggest that European catchments will become dominated by P. clarkii with climate warming. Ultimately, this might lead to impoverished biodiversity, simplified food webs and altered ecosystem services

Invasive crayfishes as a threat to freshwater bivalves: Interspecific differences and conservation implications

“…Procambarus clarkii may be more prone to predation by mammals (or other faunal groups) than P. leniusculus or the environmental conditions in the Sabor River basin are more favourable to P. leniusculus, among other hypotheses. For example, Gherardi et al (2013) showed that water temperature can affect crayfish behaviour by intensifying or lowering their aggressiveness. Although competition between P. clarkii and P. leniusculus was confirmed in the laboratory experiments, and their niches overlap, these crayfishes have numerous feeding sources (Axelsson et al, 1997;Gherardi et al, 2001;Gherardi, 2006;Guan & Wiles, 1998), which means that competition for food may be minimized in the field.…”

Complexity of biogeographic pattern in the endangered crayfish Austropotamobius italicus in northern Italy: molecular insights of conservation concern

“…Once its geographical range was wide in Europe (Souty-Grosset et al 2006), in recent years it has been drastically reduced (Holdich et al 2009) so that the species from 2010 has been classified as ''endangered'' in the ''IUCN Red List of Threatened Species'' (Füreder et al 2010); it has also been listed under the EU Habitats Directive 92/43/EEC (Annexes II and V) and therefore requires the designation of special areas of conservation for its protection. Indeed, its populations have severely suffered in the past decades from competition with exotic crayfish (Vorburger and Ribi 1999;Gherardi 2006;Gherardi et al 2013) such as Orconectes limosus (Rafinesque 1817), Procambarus clarkii (Girard 1852) and Pacifastacus leniusculus (Dana 1852), and from deadly epidemics caused by Aphanomyces astaci Schikora 1906, an oomycete responsible for the so-called ''crayfish plague'' introduced since 1850 0 s in the Po river basin (Alderman 1996; Morpurgo et al 2010). Other anthropogenic factors, including climate change, pollution, habitat destruction and fragmentation, and water depletion for agriculture and industry, have further accelerated the decline of the native white-clawed crayfish all over its range (Nardi et al 2005;Aquiloni et al 2010;Füreder et al 2010).…”

Do alien invasive species and climate change foster conservation behaviour?

“…Several behavioural studies have been conducted to assess the effect of climate change on reproduction and migration, but more behavioural research should be undertaken that combines alien species and global warming to understand the future dynamics of species and the conservation actions that are needed. For example, a recent laboratory experiment performed by Gherardi et al () analysed the agonistic behaviour of pairs composed of similarly sized males in combinations of three alien crayfish species in Europe – Orconectes limosus , Pacifastacus leniusculus , and P. clarkii – in the light of climate change. The first two species were found to reduce their agonistic behaviour at higher temperatures.…”