Award Date

Spring 2004

Degree Type


Degree Name

Bachelor of Arts


Environmental Science

Advisor 1

Dr. Patrick Drohan

Number of Pages



The desert tortoise (Gopherus agassizii) populations have been in decline and have been placed on the endangered species list. No single factor is ultimately responsible for the tortoise decline. It is a combination of events that collectively have a negative impact. I chose to focus my study on only one factor, off-road vehicles. By evaluating the damage done to the terrain by off-road vehicles, a better understanding of their impact on the tortoise populations can be assessed and protective measures taken.

The amount of available vegetation does not seem to play a role in their decisions of which plants to eat. If vehicles are destroying the native plants required by the tortoise, then a decline in population could happen. Tortoises also make a majority of their burrows next to plants to have more shade and result in being less visible. This leads to the unintentional crushing of the tortoise burrow.

Not only do these vehicles destroy burrows and vegetation they also compact the soil making plant growth more difficult while decreasing the amount of available vegetation. The amount of soil compaction will be measured by means of a bulk density analysis.

There will be one test site and one control site. Each site will be 0.6 square miles in size and the test site will have an off-road track running through the middle of it. Transects will be ran in order to record burrow locations.


Burrow destruction; Desert tortoises (Gopherus agassizii); Environmental impact; Habitat destruction; Jean; Nevada; Off-road vehicles (ORV); Soil compaction; Vegetation degradation


Desert Ecology | Environmental Indicators and Impact Assessment | Environmental Sciences | Terrestrial and Aquatic Ecology

File Format


Degree Grantor

University of Nevada, Las Vegas




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