There is no dispute that all avenues of solar development need to be explored to supply clean energy to our ever expanding human population.
The Gemini solar & battery storage project in northeastern Clark County is but one, but an important member of the industrial scale group. That’s why, as lead tortoise biologist for Gemini, I wanted to respond to your story in last week’s story, “The Tortoise vs. the Bulldozer.”
That article quoted liberally from Kevin Emmerich, director of Basin and Range Watch. While I applaud Mr. Emmerich’s conservation ethics, some of the statements attributed to him are erroneous. Perhaps most egregious is his statement that tortoises migrate, and that the Gemini project encompasses a crucial migration corridor for species preservation.
Tortoises do not migrate. That is a term reserved for animals like ungulates that move from wintering to summer grounds and back, or birds, that migrate long distances to their breeding grounds, then return to the wintering areas. By contrast, tortoises have small home ranges, generally less than a square mile, and remain there year-round.
What is important for species persistence, however, is connectivity, especially between important core populations in federally designated critical habitat. The Gemini site is neither in nor near critical habitat, but it is inside a mathematically modeled, broad connectivity corridor extending from Las Vegas to Mesquite.
As with most models, site-specific factors must be considered and the U.S. Fish and Wildlife Service did this at Gemini. In their Biological Opinion for Gemini, they evaluated connectivity, concluding that “opportunities for desert tortoise connectivity would be modified by construction of the Project, but not significantly.”
Limiting loss of habitat
We are undertaking an extensive effort to minimize the obvious loss of habitat that will occur at the Gemini site. The project is mowing, rather than completely blading 65% of the site, for example. Without doubt, the site will be altered by maintenance roads and fields of panels. That said, the mowing is required to be only to 18-24” above the ground surface.
The dominant plant species on the site, burrobush, is shorter, so will be less affected, although it will most certainly be crushed in some locations during the construction process. Fortunately, this is also a colonizing species and will bounce back quickly.
Other less abundant, taller species will be affected, and some will never re-grow. But the hope is that the altered habitat can still support many desert species, including desert tortoises. If tortoises can still thrive in the altered and surrounding unaltered landscape, then this will be a vast improvement over the razed landscapes of nearly all other industrial scale solar projects.
Future management decisions
The ISEGS project at Primm was the first desert solar project to mow, rather than blade, and the habitat has re-grown substantially; it was the inspiration for mowing at Gemini. Unlike Gemini, tortoises were not permitted to re-occupy that site, but the Bureau of Land Management, Fish and Wildlife Service, and I feel strongly that tortoises will re-occupy the Gemini site.
Our investigations will center on how tortoises re-use the site, as well as on vegetation re-growth and introductions of non-native species. Several detailed scientific studies have been developed and peer-reviewed to examine these factors. While research can never replace lost or highly disturbed habitat, it can provide critical insights into future management decisions, including continued green-energy development in the southwestern deserts.
Alice Karl has two advanced degrees on desert tortoises and 44 years studying tortoises, rare plants and ecology in the southwestern deserts and Mexico. She has co-authored several papers, including describing a new species of tortoise in Mexico, and has been the principal investigator on many research projects. She has developed and/or contributed to many of the current protocols used for desert tortoises. She has led several translocation projects, including the largest translocation project to date.