Field evidence of dispersal of branchiopods, ostracods and bryozoans by teal (Anas crecca) in the Camargue (southern France)

Abstract

Invertebrate propagules may survive internal and external transports by waterbirds, thus facilitating their dispersal between aquatic habitats. However, field data on such transport remain limited, especially for exozoochory. We quantified and compared the rates of internal and external invertebrate transports simultaneously in a wintering population of teal (Anas crecca) in the Camargue (southern France). We inspected lower gut (rectum) contents of birds that had been shot (N = 366) and washed birds that had been live-trapped (N = 68) during the winters 2006-2007 and 2007-2008. At least one propagule was recorded in 2.5% and 10.3% of internal and external samples, respectively. Cladoceran, ostracod, plumatellid bryozoan and anostracan propagules were all recorded in both internal and external samples. Hatching confirmed their viability, except for anostracan eggs. At least three cladoceran species and two ostracod species were recorded, none of which had previously been shown to be dispersed by birds. Amongst external samples, we recorded a significant seasonal trend in 1 year with most propagules recorded before December, keeping with a seasonal decline in the availability of propagules on the water surface. This study provides evidence that teal may be important vectors of invertebrate dispersal both within the Camargue and along migratory flyways.

Strong potential for endozoochory by waterfowl in a rare, ephemeral wetland plant species, Astragalus contortuplicatus (Fabaceae)

“…Seeds and fruits of vascular plants [3][4][5], eggs of aquatic invertebrates [6][7][8][9], and algal spores and cysts [10,11] can all be disseminated by birds. Such dispersion with the help of animal vectors is called zoochory, of which there are two main types.…”

Subfossil statoblasts of Lophopodella capensis (Sollas, 1908) (Bryozoa, Phylactolaemata, Lophopodidae) in the Upper Pleistocene and Holocene sediments of a montane wetland, Eastern Mau Forest, Kenya

“…Although not observed related to L. capensis, birds have been shown to be associated with the distributions of some freshwater bryozoans (Freeland et al 2000;Figuerola et al 2005). Possible pathways include feather and skin attachment and ingestion and subsequent excretion after traveling (Brochet et al 2010). Since waterborne dispersal is possible by lophopodid taxa (Wood 2009), the ecological range may include parts of the Lake Victoria Basin and ultimately the Nile, at least during certain intervals of the Late Pleistocene and Holocene.…”

A review of rice field ostracods (Crustacea) with a checklist of species

“…Generally, their main predators are fish, waterfowl, amphibians, insect larvae (notably dragonfly and damselfly), backswimmers, and water mites (Lowndes, 1930;Proctor, 1964;Lilly et al, 1978;Vinyard, 1979;Allen and Wootton, 1984;Proctor and Pritchard, 1989;Griffiths et al, 1993;Uiblein et al, 1994;Lopez et al, 2002;Blanco et al, 2004;Ghioca-Robrecht and Smith, 2008;Brochet et al, 2010;Vandekerhove et al, 2012), all common in rice field ecosystems. The hard, calcified carapace of ostracods can reduce predation considerably in some cases.…”