Human Impacts

Inroduction, with historical timeline

Native peoples

   who they were, history and distribution

   food, products, remedies

   petroglyphs 

Modern man

   Mining

   Ranching/ grazing

   Water use/ irrigation/ damming of rivers

   Habitat destruction by urbanization, roads, recreational use, introduction of invaders and other habitat alteration (e.g.night blooming cereus)

During America's Great Depression, unemployment reached 25%. In March 1933, President FD Roosevelt established the Civilian Conservation Corps. Men from 18 to 25 years old were recruited for conservation work in the national parks and forests. In the Tucson (Arizona) area, the CCC workers erected picnic facilities, sunk wells that provide spring water to support desert wildlife, constructed masonry dams to prevent erosion from storm water, and laid out many of the hiking trails that are still used by visitors to the protected areas of the Sonoran Desert. The CCC programme ended in 1942, shortly after America entered the Second World War, but there remains a lasting testimony to this programme, as seen in the images below. In fact, quite rightly, these structures have assumed the status of historical monuments.