The Ecology of Compromise: The Desert Tortoise and the Solar Farm


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Is this a question of tortoise power versus solar power?   Image by bosshog at Stock Exchange.

The deserts of the world look like an untapped well of nearly unlimited sunshine. As oil reserves gradually deplete and climate change becomes even more of a reality, the push for renewable energy has become more urgent. Just like oil needs to come from oil deposits and wind farms work best in places that are windy, solar energy works well in places with lot of sunlight. The Mojave desert is one such place, and the Desert Sunlight Solar Farm has plans to build on 4000 acres of this desert, creating enough energy for 165,000 homes. But there are twenty five tortoises that don’t like the idea.  Those 4000 acres are their home.

Green Versus Green?

The story is a journalist’s delight. In the ring today it’s green against green: renewable energy against species conservation. Who will win? Do the environmental benefits from green energy equal the loss of animal habitat? However, like any boxing match, there is a more subtle background behind this debate, one that leads in directions that are far more complex than green against green.

No matter how green its energy output, any large-scale construction project will have its consequences. Since people started creating energy on a large scale, there have been conflicts between energy projects and individual species.  Gas pipelines interrupt caribou migrations. Dams wipe out huge swathes of land: plants, animal habitat, and peoples’ homes sink beneath the water used to power hydroelectricity projects.  So when the solar farm comes to town, there will also be changes.

Solar Energy from Solar Farms: A Boon to the Environment?

Even if it is renewable, no energy source is completely green. Image by dynamix at Stock Exchange.

Let’s weigh the solar energy side of the equation. Solar energy is renewable, but creating solar farms uses energy, materials, and land. Creating, storing, and moving solar energy is not the most efficient process. However, the energy that the solar farm creates is energy that does not come with a side of climate change. Climate change is a threat to species everywhere, and these species include the desert tortoise. Since it already survives in an ecosystem that is very hot and tough to inhabit, climate change could impact the tortoise’s ability to live in the desert. Warmer weather also reduces the number of eggs the female tortoises lay. Reducing climate change would be to the benefit of the desert tortoise.

But what is the impact of one solar farm? What would its impact be if it could move elsewhere? It’s hard to quantify exactly what the impact is when climate change is deferred. It’s even harder to quantify exactly how this balances out with the loss of an increasingly rare species.

The Appeal of the Desert Tortoise

What about the argument for saving the tortoises?

We can’t deny the appeal of these ancient animals. The appeal of a species is sometimes referred to as sexiness. Every species is important, but only some species are sexy. Mammals and longer-lived animals such as tortoises appeal to the human psyche. Perhaps they seem more human and therefore more valuable. Wildlife conservation campaigns have historically used these sexy species as the face of a habitat. Would we care if the species in question were a rare sort of worm?

From an ecology perspective, the desert tortoise has an important role to play in its desert home. Although every species is important, some species act as ecological glue, allowing the entire system to hold together. These species are so critical that ecologists have a special name for these species: keystones. The desert tortoise digs burrows that other animals use, and it moves the seeds of desert plants. Some consider it to be a keystone species in the Mojave ecosystem.

For the tortoises, the Desert Solar Farm has offered over 7000 acres of land. Unfortunately, habitat creation programs for species are hard to develop successfully, mostly because species like to live where they are for a reason. They enjoy the food sources and the microclimate of a particular location. While it is entirely possible to develop habitat that suits a particular animal, the animal still may not thrive. Fruit flies can adapt quickly to change because the length of their generations is very short. Tortoises live longer and breed much more slowly.

The Ecology of Compromise

With enough number crunching, it might be possible to wrangle out a logical answer to this problem, to compare climate change deferred with the ecological impact of the tortoise. But that is not where the answer lies. Ecology does not understand the irony of human perceptions: the idea that a green form of energy could be detrimental to animal life. Ecology has a lot of metrics, but it doesn’t have a means of weighing the values that humans attach to particular species.

The solar farm and desert tortoise debate pits the one against the many. It’s an argument that is hard to win. The solution? Don’t win it. Creating acceptable solutions for all is a challenge, but it is also a discussion process that will occur over and over again as renewable energy installations grow around the country and around the world.


The Desert Tortoise. Mojave Desert Ecosystem Portal.  Accessed August 19, 2011.

Desert Sunlight Solar Farm Fact Sheet. US Department of the Interior. Accessed August 19, 2011.

Desert Tortoise Conservation Heating Up. San Diego Zoo Institute. Accessed August 19, 2011.


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