Using movement to inform conservation corridor design for Mojave desert tortoise

Area of Science:

• Ecology
• Conservation Biology
• Wildlife Movement

Background:

• Habitat fragmentation due to human activity threatens species recovery.
• Connectivity corridors are essential for maintaining gene flow among populations.
• The Mojave desert tortoise (Gopherus agassizii) is a threatened species requiring habitat connectivity.

Purpose of the Study:

• To characterize natural corridors used by desert tortoises.
• To understand how tortoises move within their habitat and interact with human infrastructure.
• To inform the design of effective connectivity corridors for threatened species.

Main Methods:

• GPS dataloggers were used to track fine-scale movements of desert tortoises.
• Path selection functions and resistance surfaces were developed based on landscape characteristics.
• Home ranges were estimated using autocorrelated kernel density methods.

Main Results:

• Tortoises avoided steep slopes and areas with sparse vegetation.
• Movement near low-density roads was avoided, but tortoises utilized linear barriers like fences.
• Differences in movement resistance and home range size were observed between natural corridors.

Conclusions:

• Mitigation corridors must be sufficiently wide to support tortoise home ranges and function.
• Natural corridors vary in functionality, impacting genetic connectivity.
• The design of mitigation corridors, especially those with fences, needs careful consideration to avoid unintended consequences and ensure effectiveness for species conservation.