I wanted to make a post about the Sonoran Desert just to provide some context, about why we post plants from this area of the world. As some of you know, I am originally from Mexico, specifically from Mexicali, B.C., but I grew up and lived for many years in Cd. Constitución and La Paz B.C.S.
For some strange reason, I never knew that these cities were in the Sonoran Desert, I knew about the sub-regions such as the Llanos de Magdalena and the Vizcaíno Desert; but it wasn't until I moved to Tucson, Arizona that I started hearing more and more about the Sonoran Desert by itself.
This beautiful desert is shared between two nations: the United States of America and Mexico, encompassing the states of Arizona, California, Sonora, Baja California and Baja California Sur. It is considered the hottest desert in Mexico and the United States; and it is the most biodiverse in the world, which means that it has many different species of fauna and flora, the best known worldwide are the columnar plants such as cardones and saguaros.
Its natural history tells that 65 million years ago, shortly after the dinosaurs became extinct, this area was covered with tropical plants such as ferns and palm trees. 15 million years later, coastal regions began to get hotter and that is when deciduous trees (trees that shed their leaves seasonally), began to become more common in response to increasingly frequent droughts. It is thought that it was in these times when cacti originated in this dry-tropical climate and it was shortly after this, when "modern" reptiles such as turtles and lizards began to form part of the ecosystem. A series of huge volcanic eruptions 23 million years ago caused major changes in this area.
In Mexico the great Sierra Madre arose and this caused changes to the north, since this elevation limited the tropical climate to the coastal lands of southern Mexico and South America. It is believed that 8 million years ago the Sonoran Desert already had the characteristics that we see now, most of the plants that we now know gradually evolved and adapted to this semi-arid climate that we now have. The separation of the Baja California peninsula from the rest of the continent due to the San Andreas Fault, caused evolutions and adaptations in certain plants and animals, giving us interesting endemic species, which are only found in certain areas, especially in the islands of the Pacific and the Gulf of California.
Of course, there is still much to explain about the natural history of this desert, but it will take me forever. If you want to learn more about the subject, I suggest the book A Natural History of the Sonoran Desert, published by the Arizona-Sonora Desert Museum and different authors.
Those of us who live in this desert we are lucky of having many different ecosystems within our reach: in Baja California North and South we have sea, islands, dunes, mountains, oases; in Arizona and Sonora we have riparian areas, wetlands and the mountains known as sky islands because they change drastically as you go up them, starting from the bottom in the desert and ending at the top with pines and firs like you're in Canada. Without a doubt, the Sonoran Desert is a unique place to live and needs to be more appreciated by all its inhabitants.
Sources:
Book: Deep History of the Sonoran Desert. In book: A Natural History of the Sonoran Desert (pp.63-70) Edition: 2nd. Chapter: 9. Publisher: University of California Press, Oakland, California Editors: Mark A. Dimmitt, Patricia Wentworth Comus, Linda M. Brewer. Online: https://www.researchgate.net/publication/305489152_Deep_History_of_the_Sonoran_Desert
Book: Native Plants for Southwestern Landscapes, by Judy Mielke. University of Texas Press, 1993.
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