Are Amphipod invaders a threat to the regional biodiversity? Conservation prospects for the Loire River

Christophe Piscart (1) , Benjamin Bergerot (2) , Pascal Lafaille (3) , Pierre Marmonier (1)

1 Hydrobiologie et Ecologie Souterraines
2 CERSP - Conservation des espèces, Restauration et Suivi des Populations
3 Biodiversité Fonctionnelle et Gestion des Territoires

The impact of invasions on local biodiversity is well established, but their impact on regional biodiversity has so far been only sketchily documented. To address this question, we studied the impact at various observation scales (ranging from the microhabitat to the whole catchment) of successive arrivals of non-native amphipods on the amphipod assemblage of the Loire River basin in France. Amphipod assemblages were studied at 225 sites covering the whole Loire catchment. Non-native species were dominant at all sites in the main channel of the Loire River, but native species were still present at most of the sites. We found that the invaders have failed to colonize most of tributaries of the Loire River. At the regional scale, we found that since the invaders first arrived 25 years ago, the global amphipod diversity has increased by 33% (from 8 to 12 species) due to the arrival of non-native species. We discuss the possibility that the lack of any loss of biodiversity may be directly linked to the presence of refuges at the microhabitat scale in the Loire channel and in the tributaries, which invasive species have been unable to colonize. The restoration of river quality could increase the number of refuges for native species, thus reducing the impact of invaders

Mots clés: species distributions; crustacean invasion; habitat; native and invasive species; refuge; colonization process; Species distributions; Crustacean invasion; Habitat; Native and invasive species; Refuge; Colonization process

Domaines: Biodiversité et Ecologie; Ecosystèmes

Christophe Piscart, Benjamin Bergerot, Pascal Lafaille, Pierre Marmonier. Are Amphipod invaders a threat to the regional biodiversity? Conservation prospects for the Loire River. Biological Invasions, 2010, 12 (4), pp.856-863. ⟨10.1007/s10530-009-9506-4⟩. ⟨halsde-00465309⟩