Comparing the potential for dispersal via waterbirds of a native and an invasive brine shrimp

Abstract

SUMMARY1. Migratory waterbirds are likely to have a major role in the spread of many exotic aquatic invertebrates by passive dispersal. However, in the field, this has so far only been confirmed in the case of the American brine shrimp Artemia franciscana, which is spreading quickly around the Mediterranean region. 2. We compared experimentally the capacity of A. franciscana and the native brine shrimp Artemia parthenogenetica to disperse via migratory shorebirds. After Artemia resting eggs (cysts) were fed to Redshank Tringa totanus and Dunlin Calidris alpina, we compared the proportion that survived gut passage, their hatchability and their retention time within the gut. We also tested the ability of cysts to stick to the feathers of Black-tailed Godwit Limosa limosa. 3. The proportion of ingested cysts retrieved from faeces was the same for each Artemia species (8%), and there were no significant differences in retention time (mean 1.2 h and maximum 10 h for A. parthenogenetica, 1.4 and 12 h for A. franciscana) or hatchability (11% versus 14%). The two shorebird species showed similar retention times and retrieval rates, but cysts recovered from Dunlin had a significantly higher hatchability. Only one of the 1000 A. parthenogenetica cysts and three of the 1000 A. franciscana cysts stuck to feathers. 4. These results indicate that both non-native and native brine shrimps have a similar high capacity for endozoochory via birds, and that the invasiveness of A. franciscana is probably explained by its competitive superiority owing to high fecundity and release from cestode parasitism. Owing to their different migratory behaviour, Redshank and Dunlin are likely to have different roles as brine shrimp vectors. Brine shrimps provide a suitable model for understanding the role of birds in the dispersal of exotic aquatic invertebrates.

How Far Could the Alien Boatman Trichocorixa verticalis verticalis Spread? Worldwide Estimation of Its Current and Future Potential Distribution

“…Small-scale dispersal of species is mainly due to natural means such as passive transport by wind [20] or migratory waterbirds [75], [90]. Waterbirds have already been shown to disperse dipterans [91], [92], and corixid eggs can be abundant in their faeces within the Tvv range [93], although their viability after gut passage has not been assessed.…”

Bird migratory flyways influence the phylogeography of the invasive brine shrimp Artemia franciscana in its native American range

“…Birds can disperse cysts between habitats either externally -attached to their feathers or feet -or internally in their digestive tract (Brochet et al 2010b;Green et al , 2013Sánchez et al 2007Sánchez et al , 2012. Research showing the internal transport of viable A. franciscana cysts in the field by the American Avocet, Recurvirostra americana (AJG, unpublished data), confirms shorebirds as an effective agent of dispersal in North America (see also .…”

Ecosystem services provided by waterbirds

“…Many of these organisms are incapable of moving between lakes or river catchments of their own accord, and are too large to disperse effectively by wind, making waterbirds the most important vectors that ensure maintenance of metacommunities and gene flow among populations (Figuerola, Green & Michot, 2005). Like seeds, invertebrates are dispersed both within the digestive tract of waterbirds and by sticking to feathers, feet and bills, although the former means is most common (Brochet et al, 2010;Sánchez et al, 2012). In addition, waterbirds act as vectors for microbes such as phytoplankton, diatoms, ciliates and the spores of bacteria, archaea and fungi (Schlichting, 1960;Thornton, 1971;Figuerola & Green, 2002;Green et al, 2008;Brito-Echeverria et al, 2009), although our current understanding of the importance of their role compared to other dispersal modes such as wind is extremely limited (Wilkinson et al, 2012).…”

“…For example, Levey, Tewksbury & Bolker (2008) consider 'long-distance dispersal' by terrestrial birds to be that over 150 m. By contrast, distances that seeds and eggs are moved by aquatic birds remain unclear and poorly studied, but generally much greater distances can be expected, with maxima of hundreds of kilometers likely for many migratory species (Green et al, 2002b;Figuerola et al, 2010;Sánchez et al, 2012;Viana et al, 2013). However, there is an urgent need to integrate new studies of bird movements using the latest global positioning system (GPS) technologies with studies of seed dispersal, to produce accurate seed shadows.…”