Desert Tortoise Study Field Notes

1992 – 1997

One of the park’s longest running scientific investigations is the over 40-year study of its population of the desert tortoise (Gopherus agassizii). Early field notes contribute to scientists’ understanding of current tortoise populations.

The Mojave population of the desert tortoise has been federally recognized under the Endangered Species Act as a threatened species since 1990. Surveys indicate an estimated three tortoises per square kilometer in areas of good habitat, for a total of 3,000 in the park. Once widespread, the tremendous decline in tortoise populations has been tied to drought, climate change, and increased human activity.

Paper, cloth.
Joshua Tree National Park, JOTR 20578