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Conservation
The Chametla-El Centenario salt marsh is located in the southern part of the Ensenada de La Paz and extends some 6 kilometers. The beach is composed of a fine grained substrate with salt horizons, intercalated with clay and mud. Due to the slight gradient, the sea level greatly affects the feeding area available to shorebirds. During low tide some 500 to 1000 linear meters are exposed, while during high tide the water may reach the berm. The vegetation in the salt marsh is scrub and cactus in the higher areas; red mangrove (Rhizophora mangle), black mangrove (Avicenia germinans), and Salicornia spp. predominate in the zone bordering the sea. At least 20,000 shorebirds use the WHSRN site annually. The most common are: the Western Sandpiper (Calidris mauri, 50.5% of the total number observed), Marbled Godwit (Limosa fedoa, 7.2%), and Semipalmated Plover (Charadrius semipalmatus, 4.2%). The California Least Tern (Sterna antillarum browni) nests in Chametla-El Centenario in higher areas away from the shoreline. Two plovers, Wilson’s Plover (Charadrius wilsonia) and the Snowy Plover (Charadrius alexandrinus) as well as the American Oystercatcher (Haematopus palliatus) also nest there. In addition, several species of herons nest in the mangrove area including the Great Blue Heron (Ardea Herodias), Reddish Egret (Egretta rufescens), Black-Crowned and Yellow-Crowned Night Herons (Nycticorax nycticorax and Nictanassa violacea), Little Green Heron (Butorides virescens), and White Ibis (Eudocimus albus). Possible threats are: (1) a tourism mega-project within Ensenada de La Paz, facing the Chametla-El Centenario beaches, that will most likely cause disturbances during construction as well as changes in water current and sediment patterns due to dock construction; (2) solid waste discharges (plastic, rubber, tires, etc.) and occasional gasoline and lubricant spills that, although currently moderate, could become a serious problem as the population grows; (3) possible future construction degrading the site due to necessary depositing of terrigenous sediment fill, as seen in similar projects already built in other parts of the lagoon., such as the Fidepaz Marina.
Carmona et al. (2003) recorded nine new and rare shorebirds in Ensenada de La Paz. Four of these were observed in Chametla-El Centenario: the American Golden Plover (Pluvialis dominica), the first recorded for the Bahía de La Paz; the Terek Sandpiper (Xenus cinereus), the first recorded for Mexico; the Red Knot (Calidris canutus), the second recorded for the Bahía de La Paz; and the Semipalmated Sandpiper (Calidris pusilla), the first recorded for Baja California Sur. Brabata (1995) assessed the importance of Chametla as a feeding, resting, and wintering area for the Marbled Godwit (Limosa fedoa), Willet (Catoptrophorus semipalmatus), Whimbrel (Numenius phaeopus), and Long-billed Curlew (Numenius Americanus), as well as for its abundant resources and seasonal variations. She observed that these species preferentially utilized the intertidal mudflats for feeding and the brackish flats (upper portion) for resting. Fernández et al. (1998) drew similar conclusions for the Western Sandpiper (Calidris mauri), the most abundant species in the zone. Galindo-Espinosa (2003) assessed the utilization patterns of the Western Sandpiper (Calidris mauri) in the coastal area (Chametla-El Centenario beaches) and in an artificial freshwater area (the oxidation pools). He found that the population structure by sex had a 4:1 male to female ratio as opposed to the global ratio of 1:1. However the beach contained 80% adults and the pools 80% juveniles. The Western Sandpiper (Calidris mauri) utilized Chametla-El Centenario in the autumn and winter, while in contrast they utilized the pools mainly in the autumn. Carmona et al. (2003) evaluated the effect of tide level on shorebird abundance on Chametla beach and the oxidation pools in the autumn and winter. They observed the behavior of three types of species: 1) exclusively marine environment species, 2) species that only utilize the freshwater zone and 3) generalist species who utilize both environments. For the generalists, in particular the Western Sandpiper (Calidris mauri), they observed a greater use of the oxidation pools in the autumn, and of Chametla beach in the winter, which corresponds to a greater energy demand during the migratory season. Recently, Vázquez (under review) determined a general rate of return for the Western Sandpiper (Calidris mauri) of 56%, with a greater proportion (65%) being males, compared with the females (40%); by age there were no differences among first year adults and second year adults and older. |
Site Facts
Country, State,
Province/Region: Baja California Sur, Mexico Relative Location: The inlet is on the southeast coast of the Baja California peninsula, opening onto the Gulf of California. The city of La Paz is adjacent to the WHSRN site. Latitude/Longitude: 24º 06' 0.8" N, 110º 25' 24" Category: Regional site Basis for Designation: More than 20,000 shorebirds use the site every year. More than 1% of the biogeographic populations of the Snowy Plover (Charadrius alexandrinus), Semipalmated Plover (Charadrius semipalmatus), Whimbrel (Numenius phaeopus), and Marbled Godwit (Limosa fedoa) have been recorded there. Size: 194 hectares/479 acres Joined:
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