Abstract

MORENO-HIGAREDA, Hiram Rafael et al. Is an exotic bivalve threatening the Ridgway’s Rail in Baja California?. Huitzil [online]. 2019, vol.20, n.2, e531. ISSN 1870-7459.  https://doi.org/10.28947/hrmo.2019.20.2.454.

We describe the presence, structure, number of eggs, and hatching success of Rallus obsoletus levipes (Ridgway´s rail), a bird species protected in Mexico and the USA, during the 2016 to 2018 nesting seasons at Estero Punta Banda (EPB), Ensenada, Baja California, Mexico. The number of eggs per nest was 6, 7, or 8, and hatching success 0, 75, or 100%. We document the presence, abundance, and density of Geukensia demissa, (Atlantic ribbed mussel) an invasive bivalve in the estuary study area. G. demissa density per marsh area: Internal Marsh (MI) 5.36/m2, Middle Marsh (MM) 6.94, and External Marsh (ME) 3.52. G. demissa density isn’t independent of marsh area, p < 0.001. We document the dead of two R. o. levipes chicks found trapped and dead in the G. demissa valves during EPB high tides. We did not find an association between dominant vegetation, Spartina folios and Salicornia spp. and the presence of G. demissa. Its presence seems to be independent of vegetation presence. The permanence of R. o. levipes at EPB depends on a better knowledge of the population and its interaction with G. demissa and other threats at EPB. We discuss the role of G. demissa in the future of R. o. levipes at EPB. New proposals have to be made such that sites with an elevation higher than the mean tide level are considered as critical for the nesting and survival of the bird.

Keywords : Estero Punta Banda; Ramsar site; endangered species; invasive species; predation.

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