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On the Wildlife of Wetlands of the Mexican Portion of the Rio Colorado Delta





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The delta of the Colorado River, praised for its wealth of wildlife, has been dramatically altered by agriculture. In this article we provide a basic over- view of the status of the aquatic wildlife of this area. Overall there is a great lack of knowledge on the status of the different aquatic species in the area, but negative impacts include the disappearance of the massive riparian forests, a reduction in the populations of native fish (very severe), a number of birds, two mammals, and possibly one amphibian and two reptiles. Conversely, habitat transformation might have benefited some amphibians, some birds, and one mammal. Alien aquatic taxa that have been introduced to the area or have colonized it include some plants, 4 invertebrates, more than 20 fish species, 3 amphibians, 3 reptiles, and 1 bird. We conclude that the area is far from being biologically intact, and that it does not meet the legal criteria for being a Biosphere Reserve, as it has been declared. Listing of some of the species as at risk is unsupported. Although the area is biologically very modified, it can provide important opportunities for the conservation of wetland taxa.