Both the US and Mexico make available free, high quality, detailed topo maps at various scales!

Download US topo maps at the USGS Store. Use the locator map to find your desired location, then click to get a location bubble, which you then click on for a list of available maps for the area. PDFs are available for free download. Various types, scales, and editions are often available. In recent times (2018) the website seems to have occasional issues.

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The Apachian-Madrean region is a zone of confluence and geographic termini of species and floras from the north and the south. Lower and intermediate elevations support many taxa of tropical plants and animals that are at their northernmost limits. It is a region of tremendous habitat diversity and species richness. Much of the region remains little known, and quantified data are scarce. This report offers brief synopses on the insect fauna, ichthyofauna, herpetofauna, avifauna, mammals, and…

More info on spiny-tailed iguana at the Tucson Herp Society.

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This was a long trip over a short distance. A large cadre of biologists from Arizona and Sonora made the trip to enhance biological data about the mountain and region.

The trip was initiated near Nacozari de Garcia with the destination being the high point of the Sierra el Tigre just above the small community of El Tigre.

We traveled through the La Caridad Mine and across Rio Bavispe at La Angostura Reservoir, then north near the eastern edge of the reservoir, before heading…

The Sierra la Mariquita was decreed a Voluntary Protected Natural Area on May 12, 2015. This Sky Island is owned by the Instituto Nacional de Astrofiscica (the Mexican national astronomy organization).

The Sierra San Francisco is a low-desert mountain range at the edge of the Gran Desierto of northwest Sonora. This range is owned by an ejido and protected as desert bighorn sheep habitat.

Early 2015 was quite lush due to good winter rains and previous-year hurricane remnant moisture.

By Huck

Recently I had the opportunity to see, by raft, the country I've been tramping overland for the last couple of decades. Just getting to the put-in of our trip was a logistical conundrum and an exercise in patience. We needed a shuttle driver who was comfortable in the fringe area of Copper Canyon, Chihuahua, and the driver might have to spend two, maybe three nights on the road before getting home. Then he would have to pick us up in 10 or 11 or 12…

Peter Warshall was able to excel in many divergent endeavors. He chose to put his multi-faceted talent into bettering the world. I knew him through struggles to protect Mt Graham, interests in biogeography, and work to protect jaguars and other species in eastern Sonora. Any time I read or hear stories about Peter, I learn of another aspect of his work that is surprising and admirable. Conservation Biology recently published an obituary for him by Joel Helfrich that is worth reading…

On August 7, 2014 ten million gallons of a mining wastewater solution broke through containment at the Buenavista copper mine just outside of Cananea, Sonora. The sulfuric acid solution was released into the Rio Bacanuchi, a tributary of Rio Sonora, one of the largest watersheds in Sonora.

Rio Sonora is a key water source for many communities including Arizpe, Sinoquipe, Banámichi, Aconchi, Baviácora, Mazocahui, and Ures, along with substantial agriculture along its lower reaches. Rio…

By Garry Rogers

(First in series on Sonoran Desert invasive plants.)

Invasive species, like storm troopers leading the surging ruin of global warming, are demolishing Earth's ecosystems.

Photograph: Once diverse landscape of small trees and tall Saguaro cactus was converted to impoverished shrubland after invasion by fire-prone plants.

Once they began crossing the oceans, Humans introduced thousands of…