MESOAMERICANA - Sociedad Mesoamericana para la Biología y la ...

Mesoamericana 13 (1) Agosto de 2009
worm Peloscolex gabriellae (Poff, 1973) were found to be
favored by the soft and highly organic sediments where
these plants grow. On the other hand, wigeongrass has
been referred to be an important food item for various
classes of mollusks such as the gastropod Cerithidea
mazatlanica in a Mexican lagoon (Edwards, 1978), the
marine crabs (Callinectes spp.) in a North Carolina estuary
(Copeland et al., 1974) and in south Florida (Zieman,
1982).
Wigeongrass beds are heavily used by fish in coastal
wetlands (Kantrud, 1991) and in some inland waters
(Terrell, 1923) by providing excellent food and cover.
Generally, the plant stands are more often used as a
nursery than as a food resource since just a few species
consume this angiosperm and its detritus (Hildebrand and
Cable, 1938; Sculthorpe, 1967; Austin and Austin, 1971;
Congdon and McComb, 1981).
Among amphibians and reptiles, the Rana and
Xenopus tadpoles in an African estuary (Millard and Scott,
1953) and water snakes (Natrix sipedon) and American
alligators (Alligator mississippiensis) in the SE United States
(Heitzman, 1978; Epstein and Joyner, 1986), were found
common where wigeongrass was abundant. Besides, the
plant has also been noted to be an important food of
some sea turtles (Felger et al., 1979).
This angiosperm is also recognized worldwide as an
important food of migrant and wintering waterfowl,
wading birds and shorebirds (Figuerola et al., 2002); and its
stands can be quickly and entirely consumed by the
wintering waterfowl in subtropical climates according to
Kantrud (1991). In general, various families of waterbirds
are known for feeding on different parts of the
wigeongrass plants such as coots (Fulica spp.) (Swiderek,
1982), red knots (Calidris canutus); dowitchers
(Limnodromus spp.) and common snipes (Gallinago gallinago)
(Sperry, 1940), purple gallinules (Porphyrio martinica),
black-necked stilts (Himantopus mexicanus), and king rails
(Rallus elegans) (Martin et al., 1951), yellowlegs (Tringa spp.)
and willets (Catoptrophorus semipalmatus) (Bourn and
Cottam, 1950) as well as flamingoes (Phoenicopterus spp.)
(Allen, 1956).
Lastly, in the case of mammals, only some wild
species are known to consume living wigeongrass such as
West Indian manatees (Trichechus manatus latirostris)
(Hartman, 1971), muskrats (Ondatra zibethicus) (McCabe,
1982), and nutria (Myocastor coypu) (R. H. Chabreck, pers.
comm. in Garner, 1962). Deer and cattle sometimes eat
detached plants windrowed along shorelines (Campbell,
1946).
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However, despite the high diversity of the taxonomic
groups aforementioned, birds have been especially
highlighted due to being long considered the main
candidate for dispersion of numerous organisms lacking
autonomous long-distance dispersal, but showing wide
geographic ranges (Malone, 1965). For any bird-mediated
dispersal (internal transport) event to occur a series of
main steps should be followed according to the
statements of Figuerola and Green (2002): (1) propagule
ingestion process (diet composition), (2) survival after
digestion and (3) gut time retention. These three steps
have been treated in recent literature, for instance, diet
studies of migratory waterfowl (Anatidae) have shown
that large quantities of propagules of aquatic organisms
are consumed by a wide variety of species, especially
ducks (Cramp and Simmons, 1977; Thomas, 1982).
However, there is little information about retention times
of propagules in waterbirds; most of them referred to
Anas duck species (Swanson and Bartonek, 1970; Agami
and Waisel, 1986). These authors reported retention times
of 10–12 h and over 72 h for Najas marina seeds in Anas
platyrhynchos (Mallard) and Scirpus seeds for Anas discors
(Blue-winged teal).
Among the main insular groups surrounding the isle
of Cuba, the Sabana-Camagüey archipelago and
specifically Cayo Coco, has been the best studied one in
regard to its ornithofauna (Rodríguez et al., 1997) and
highlighted for sheltering numerous species, up to 221
(Parada et al., 2006), as well as abundant populations of
neotropical migrant birds travelling southward through
the Atlantic coast corridor. In this respect, Cayo Coco
exhibits the highest values of abundance of the
aforementioned species compared to other locations in
Cuba (Rodríguez and Sánchez, 1995; Wallace et al., 1996)
and that is why the conservation of these coastal
ecosystems has a striking significance at the local and
regional scales (Rodríguez et al., 1997).
Knowing the importance of the ecology of this
macrophyte for the management of waterfowl habitat
worldwide, and the numerical representativeness of
waterfowls in Cuba, especially ducks in coastal and
freshwater wetlands during winter season, we here discuss
the probable dispersal means involved in the newly
discovered locality of R. maritima in a coastal lagoon in
Cayo Coco, based on published literature approaching
endozoochory processes and previous inventory surveys
on waterfowl.