S2E16: 90 Miles from Needles: Protecting the Desert Bighorn Sheep

By Chris Clarke

In our latest episode, we delve into the world of the desert bighorn sheep and the challenges they face in the Mojave Desert. Joining us is Dr. Christina Aiello, a renowned bighorn sheep biologist who has dedicated her career to studying these magnificent creatures. We explore the threats they encounter, the importance of their habitat, and the efforts being made to ensure their survival. But first, we announce that longtime co-host Alicia Pike has left the podcast in favor of other projects. We miss her already.

The Threats to Desert Bighorn Sheep

One of the major threats facing desert bighorn sheep is habitat loss and fragmentation due to urbanization and infrastructure development. As human populations expand, natural habitats are being converted into human systems, leaving the bighorn sheep with limited resources and restricted movements. Dr. Aiello explains, "Developments like large-scale solar expansion, military bases, and urban areas are reducing available habitat and forcing bighorn sheep to restrict their movements to smaller and smaller areas."

Another significant threat is the spread of diseases, particularly respiratory diseases caused by mycoplasma bacteria. Dr. Aiello highlights the similarities between the threats faced by desert bighorn sheep and desert tortoises, stating, "Both species are hugely impacted by habitat loss, diseases, and the shifts caused by climate change."

The Ideal Habitat for Desert Bighorn Sheep

Desert bighorn sheep thrive in higher elevation, rocky terrain within the desert environment. They primarily inhabit the mountains scattered throughout the expansive desert valleys. Dr. Aiello explains, "They target steep and rugged areas with good open visibility to avoid predators and keep their lambs safe." The sheep rely on shrubs and grasses that tap into groundwater and provide consistent forage, especially during dry periods. They also make use of natural springs and human-developed water sources known as guzzlers.

The Impact of High-Speed Rail and Fragmentation

The proposed BrightLine high-speed rail project along Interstate 15 poses a significant threat to the connectivity of bighorn sheep populations. Dr. Aiello's research has shown that the project, as currently designed, would further fragment their habitat and impede their movements. She emphasizes the importance of wildlife crossings, stating, "These crossings are crucial for the survival of bighorn sheep and other wildlife, as they facilitate their movements and allow them to access vital resources."

Soda Mountain Solar Project

As a sort of intermission, we offer a commentary by desert writer Louise Mathias on the proposed Soda Mountain Solar Project, which would be sited just west of one of the wildlife crossings slated for the BrightLine High Speed Rail project. Construction of the project would essentially sabotage the crossing by providing a strong deterrent to bighorn sheep using the area.

The Resilience of Desert Wildlife

Despite the challenges they face, desert bighorn sheep exhibit remarkable resilience. Dr. Aiello shares her observations of wildlife using degraded areas, stating, "Animals will make use of a bad situation that we hand them and get as much from the landscape as they can, regardless of what we've done to it." She emphasizes the need to protect and improve these areas, as wildlife can still thrive in them.

The Importance of Genetic Diversity

Genetic diversity plays a crucial role in the resilience of bighorn sheep populations. Dr. Aiello explains that populations with robust genetic diversity and good connectivity are better equipped to fight infections and adapt to changing environments. She highlights the need to maintain and improve connectivity between populations to preserve genetic diversity and ensure the long-term survival of the species.

Conclusion and Future Outlook

The conservation of desert bighorn sheep is a complex and ongoing endeavor. While the species has made significant strides towards recovery, there is still much work to be done. Protecting their habitat, mitigating the impacts of development, and preventing the spread of diseases are crucial steps in ensuring their survival.

Dr. Aiello's research and the efforts of conservation organizations provide hope for the future of desert bighorn sheep. By understanding their needs, advocating for their protection, and implementing measures to enhance connectivity, we can secure a brighter future for these iconic desert dwellers.

As we move forward, it is essential to recognize the interconnectedness of all species and the importance of preserving the delicate balance of our ecosystems. By working together, we can ensure the survival of not only the desert bighorn sheep but also the diverse array of wildlife that call the desert home.

2024 promises to be an exciting year for 90 Miles from Needles, including a search for a small group of new co-hosts and a February road trip through the southwestern deserts. We’ll be officially launching the website for the Desert Advocacy Media Network in late January, and we expect to put out episodes with much greater regularity and frequency.

If you like our podcast, tell a friend! Or tell all your friends by posting to social media. Every new pair of ears helps us.

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This newsletter is a project of the nonprofit Desert Advocacy Media Network. D.A.M.N. also produces the 90 Miles from Needles desert protection podcast and Letters From the Desert, an email newsletter by desert writer Chris Clarke.