Native and exotic Amphipoda and other Peracarida in the River Meuse: new assemblages emerge from a fast changing fauna

Abstract

Samples issued from intensive sampling in the Netherlands (1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001) and from extensive sampling carried out in the context of international campaigns (1998, 2000 and 2001) were revisited. Additional samples from artificial substrates (1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003) and other techniques (various periods) were analysed. The combined data provide a global and dynamic view on the Peracarida community of the River Meuse, with the focus on the Amphipoda. Among the recent exotic species found, Crangonyx pseudogracilis is regressing, Dikerogammarus haemobaphes is restricted to the Condroz course of the river, Gammarus tigrinus is restricted to the lowlands and seems to regress, Jaera istri is restricted to the 'tidal' Meuse, Chelicorophium curvispinum is still migrating upstream into the Lorraine course without any strong impact on the other amphipod species. After a rapid expansion Dikerogammarus villosus has continued its upstream invasion between 1998 and 2002 at a rate of 30-40 km per year, but no further progression was noticed in 2003. Locally and temporarily the native species (Gammarus fossarum and G. pulex) and naturalized species (G. roeseli and Echinogammarus berilloni) may have been excluded by the most recent invaders (mainly D. villosus), but none of the native and naturalized species has disappeared completely. Therefore, the number of amphipod species found in the River Meuse has increased. Moreover, the native and naturalized species keep on dominating the tributaries from which the recent invaders seem to be excluded. A changing Peracarida community structure is observed along the course of the River Meuse: four native or naturalized species inhabit the upstream (Lorraine) course, three invasive species dominate in the middle reach (Ardenne-Condroz zone), one exotic species is housed in the Border Meuse and three or four invasive species dominate the assemblages in the lowlands.

Size matters: predation of fish eggs and larvae by native and invasive amphipods

“…D. villosus reaches locally high densities (up to 10,000 m -2 ; van Riel et al 2006) which may exceed those of other amphipods in comparable systems. In the River Meuse, for example, invading D. villosus accumulates to higher densities (200-500 individuals per artificial substrate) than the previous native-naturalised community (50-120 individuals per substrate), of which G. pulex was part (Josens et al 2005). This conforms to the general pattern of aquatic invasive species reaching higher densities, on average, than native analogues (Hansen et al 2013).…”

“…The 'killer shrimp' D. villosus is spreading across Europe with significant ecological impacts, including declines in resident macroinvertebrate populations attributed to predation by the invader (Dick and Platvoet 2000;Josens et al 2005;van Riel et al 2006;MacNeil et al 2013). Since D. villosus has been observed to feed upon fish eggs and larvae, there is concern over its potential impact on biologically and commercially important fish populations.…”

“…Invasion by D. villosus frequently coincides with the decline or extinction of resident benthic macroinvertebrates such as isopods, tubificids and amphipods (Dick and Platvoet 2000;Dick et al 2002;Kley and Maier 2003;Josens et al 2005;Boets et al 2010;MacNeil et al 2013;Dodd et al 2014;Gergs and Rothhaupt 2015). Thus, once established D. villosus typically dominates the macroinvertebrate community in both number and biomass (Josens et al 2005;van Riel et al 2006).…”

“…Thus, once established D. villosus typically dominates the macroinvertebrate community in both number and biomass (Josens et al 2005;van Riel et al 2006). Trophic links and ecosystem functions can also be transformed by the invader (Dick et al 2002;Piscart et al 2011;MacNeil et al 2011;Boeker and Geist 2015).…”

The river Rhine: a global highway for dispersal of aquatic invasive species

“…This even holds true for upstream dispersal of the bivalves such as Corbicula fluminea (up to 276 km year -1 ). Josens et al (2005) reported upstream dispersal of the amphipod species C. curvispinum and D. villosus in the river Meuse at rates of 15 and 30-40 km year -1 , respectively. High upstream dispersal rates of non-indigenous macroinvertebrates in the river Rhine may be related to human mediated transport as a result of intensive shipping activities.…”