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Gomez-Sapiens M.M.,University of Arizona | Soto-Montoya E.,Reserva de la Biosfera Alto Golfo de California y Delta del Rio Colorado | Hinojosa-Huerta O.,Pronatura Noroeste A.C.
Ecological Engineering | Year: 2013

Shorebirds constitute the highest abundance group of birds that use the Upper Gulf of California and Colorado River Delta (CRD) wetlands for nesting, spring stopover and overwintering sites. From August 2005 to December 2008 ground surveys were conducted on three natural intertidal wetlands (Golfo de Santa Clara, Isla Montague and Bahia Adair) and three brackish anthropogenic wetlands (Cienega de Santa Clara, Cerro Prieto and Mesa de Andrade) in the Upper Gulf and CRD. The goal was to determine the overall importance of the CRD in supporting shorebirds, and in particular the role of the anthropogenic wetlands, which face uncertain futures. Species richness varied from 15 to 26 species among sites and 29 species were detected across sites. The most abundant species was Calidris mauri, which was most abundant in Isla Montague and Golfo de Santa Clara in winter and spring, while it was most abundant in the Cienega de Santa Clara and Mesa de Andrade wetland in spring and fall. Cienega de Santa Clara and Golfo de Santa Clara had the highest bird density with 168 and 105 individuals/ha in the peak migration month. Birds tended to use the intertidal wetlands during the winter and spring migration period while the inland wetlands were most used during spring and fall. The Cerro Prieto geothermal power plant wetlands were most used by Phalaropes species during fall migration. Bahia Adair, an extensive intertidal wetland system south of the CRD, had a low density of shorebirds (10 individuals/ha) compared to CRD sites, but it had higher species diversity and the highest proportion of large size shorebirds. This study shows the importance of both intertidal and anthropogenic wetlands in supporting shorebirds along the Pacific Flyway. Management decisions that might impact these wetlands should consider their habitat value for migratory shorebirds as documented here. © 2013 Elsevier B.V.


Hinojosa-Huerta O.,Pronatura Noroeste | Soto-Montoya E.,Reserva de la Biosfera Alto Golfo de California y Delta del Rio Colorado | Gomez-Sapiens M.,University of Arizona | Calvo-Fonseca A.,Pronatura Noroeste | And 4 more authors.
Ecological Engineering | Year: 2013

The Ciénega de Santa Clara is the largest marsh in the Sonoran Desert and the most important wetland in the Colorado River delta. We present the information on the state of the birds in the Ciénega and a checklist of the species that have been detected at the site. We also summarize the ornithological work that has been conducted and compiled recommendations for bird conservation. A total of 261 species of birds have been detected in the Ciénega de Santa Clara, representing 71% of the species known to the Colorado River delta. The birds of the Ciénega include 189 migratory species (70.4%), 49 year-round residents (18.7%), and 28 breeding visitors (10.7%). Twenty-seven species are federally protected in Mexico, four of them as Endangered, eight as Threatened, and 15 under Special Protection. The Ciénega provides critical habitat for migratory waterbirds, with maximum counts of 280,000 shorebirds in the southern mudflats, as well as for breeding marsh birds, including Yuma Clapper Rails, Virginia Rails and California Black Rails, with maximum estimates of 8600, 7150 and 400 individuals respectively. Other species of concern that occur regularly in the Ciénega include Least Bittern, Snowy Plover, Least Tern, and Large-billed Savannah Sparrow. This wetland also provides important stopover habitat for 81 species of Neotropical migratory landbirds during their northbound spring migration, particularly for Wilson's Warbler, Swainson's Thrush, Yellow Warbler, Pacific-slope Flycatcher, and Willow Flycatcher. Binational cooperation is essential to protect the Ciénega in the long-term, especially in terms of dedicating the necessary water for its maintenance. Active management actions are also becoming an important part of habitat conservation, including land protection mechanisms, sediment removal, and fire management. © 2013 Elsevier B.V.


Hinojosa-Huerta O.,Pronatura Noroeste | Guzman-Olachea R.,Reserva de la Biosfera Alto Golfo de California y Delta del Rio Colorado | Butron-Mendez J.,Pronatura Noroeste | Butron-Rodriguez J.J.,Pronatura Noroeste | Calvo-Fonseca A.,Pronatura Noroeste
Ecological Engineering | Year: 2013

Populations of secretive marsh birds (Rallidae and Ardeidae) have declined in North America in the last decades. Despite drastic habitat changes, the Colorado River delta supports four species of protected marsh birds: California Black Rail, Virginia Rail, Least Bittern and Yuma Clapper Rail. Our goal was to assess the status (2010-2011) and detect population changes (1999-2011) of marsh birds in the Colorado River delta. This effort was focused on the Cienega de Santa Clara and the recent disturbance events that occurred in this wetland (changes in inflows, dredging and wildfires), but included other areas of the delta as well. The Cienega provides critical habitat for the four species, with estimated abundance of 405 California Black Rails, 7152 Virginia Rails, 8652 Least Bitterns and 8642 Yuma Clapper Rails. Populations of these species have remained stable since 1999, with no significant trend, although with some fluctuations in some years. Other wetlands in the delta also provide important habitat, especially El Doctor Wetlands for California Black Rails and Virginia Rails, the Hardy and Colorado rivers for Yuma Clapper Rails and Least Bitterns, and Laguna del Indio for Yuma Clapper Rails. The detections of marsh birds in 2011 were amongst the highest since the monitoring program began in 1999. This was probably linked to the disturbance regime that was recreated with a series of events in the Cienega, including the dredging of sediment, variations of inflows, and an extensive wildfire. Wetlands in the Colorado River delta support the majority of breeding Yuma clapper rails and important populations of other marsh birds. As these are shared species by México and the U.S., the conservation and restoration of the delta should be a shared responsibility. Las poblaciones de las aves de marisma (Rallidae y Ardeidae) han disminuido en Norte América en las últimas décadas. A pesar de cambios drásticos de hábitat, el delta del Río Colorado mantiene a cuatro especies de aves de marisma protegidas: Ralito Negro de California, Rascón Limícola, Garcita de Tular y Palmoteador de Yuma. Nuestro propósito fue evaluar el estatus (2010-2011) y detectar cambios poblacionales (1999-2011) en las aves de marisma en el delta. Este esfuerzo se enfocó en la Ciénega de Santa Clara y los disturbios recientes que ocurrieron en este humedal (variación en flujos, dragados e incendios), pero también se incluyeron otras áreas del delta. La Ciénega provee hábitat crítico para las cuatro especies, con una abundancia estimada de 405 Ralitos Negros, 7152 Rascones Limícolas, 8652 Garcitas de Tular y 8642 Palmoteadores de Yuma. Las poblaciones de estas especies se han mantenido estables desde 1999, aunque con algunas fluctuaciones en algunos años. Otros humedales también proveen hábitat importante, especialmente El Doctor para Ralito Negro y Rascón Limícola, los ríos Hardy y Colorado para Palmoteador de Yuma y Garcita de Tular, y Laguna del Indio para Palmoteador de Yuma. Las detecciones de aves de marisma en el 2011 estuvieron entre las más altas desde que el programa inició en 1999. Este probablemente esté ligado al régimen de disturbio que fue recreado con una serie de eventos en la Ciénega, incluyendo el dragado de sedimentos, variaciones en los flujos, y un incendio. El delta del Río Colorado mantiene a la población más grande de Palmoteador de Yuma, así como poblaciones importantes de otras aves de marisma. Estas son especies compartidas por México y Estados Unidos, por lo que la conservación y restauración de estos humedales debe ser una responsabilidad compartida. © 2013 Elsevier B.V.

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