Why the Desert Tortoise is in Trouble

Tortoise populations have been declining in many areas for decades because of collecting, vandalism, loss of habitat, and disease. Government agencies have recognized the problems facing this species for many years. For example, in 1939, 1961, 1972, and 1973 the California Fish and Game Commission developed special laws to protect wild tortoises from collecting, harassment, and shooting. In June of 1989 the California Fish and Game Commission listed the tortoise as a threatened species under the California Endangered Species Act, 50 years after the first protective legislation. Many people ask why desert tortoise populations have declined. There is no single or primary cause. The situation is highly complex and varies from site to site and region to region. In most cases, there are many causes for declines. The following is a general list of typical problems:

  • illegal collecting
  • wildfire
  • vandalism
  • domestic and feral livestock grazing
  • disease
  • railroads, roads, highways, and freeways
  • persistent drought
  • recreation, including off-highway vehicles
  • release of captive tortoises
  • utility lines and corriders
  • attacks by domestic or feral dogs
  • military activities
  • predation by ravens
  • invasions of alien plants
  • agricultural development
  • urban growth
  • mineral exploration and development
  • landfills and illegal dumps
  • exploration and development of geothermal, oil, and gas resources

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