Extinction And Invasive Species

Why we should worry much less about protecting existing species, and let evolution do its work.

This is a Desert Tortoise. A proud and ancient animal with an evolutionary history stretching back 250 million years to the Permian Period. Today, the Desert Tortoise is classified as a vulnerable species, which is the lowest level of endangered species. Due to vulnerability to disease, environmental change from new plant species, and human encroachment on habitat, their numbers are in steep decline.

Massive amounts of time, money, and brain power have been spent attempting to shield this branch of life from the forces of selection. Since they were added to the list of endangered species in 1990, $200 million dollars has been spent by state and federal agencies solely on the care and feeding of the desert tortoise. Desert Tortoise conservation has gotten in the way of private infrastructure projects too. A solar company, BrightSource, planned to build a 550 MW solar farm in the Mojave desert. This project would offset thousands of tons of carbon produced by fossil fuel. Despite their importance to the fight against climate change, BrightSource’s plans were delayed for decades by Desert Tortoise conservation interests.

"BrightSource negotiated with state and federal agencies to hash out meticulously detailed protocols for collecting and relocating tortoises, also agreeing to monitor them for five years after they were moved. The company made its first concession to the tortoise during planning, giving up about 10% of its expected power output in a redesign that reduced the project footprint by 12% and the number of 460-foot-tall “power towers” from seven to three. BrightSource also agreed to install 50 miles of intricate fencing, at a cost of up to $50,000 per mile, designed to prevent relocated tortoises from climbing or burrowing back into harm’s way."

After an initial survey of the area found 16 tortoises, the U.S. Fish and Wildlife Service issued BrightSource a permit to move a maximum of 38 adults, and allowed a total of three accidental deaths per year during three years of construction. Any more in either category and the entire project would be shut down. BrightSource has paid for hundreds of biologists to survey the area and care for relocated turtles, donated millions to a Desert Tortoise Wildlife Management Area, and relocated thousands tortoises. Still, the national environmental group Defenders of Wildlife filed a notice of intent to sue the government to stop the project, citing violations of the Endangered Species Act, which the desert tortoise is protected under.

Any reasonable cost benefit analysis would be appalled at this series of events. Hundreds of millions of dollars, thousands of highly trained man-hours, and years of delay for renewable energy, all for a few tortoises. This is just one endangered species. There are thousands on the list, spread out across the entire country, each with the same costly protections. How did we get here? Why do we sacrifice so much trying to continue these branches of life?

The most common and powerful justifications for protecting species from extinction are: A desire to mitigate human impact on the environment, the inherent value of biodiversity, and the instrumental value of biodiversity.

Mitigating Human Impact

This argument for protecting certain species from extinction rests on the claim that human impact on the environment is significantly different from impact from any other animal or natural force. It concludes that we should strive to let extinctions and invasive species play out as they would if humans did not exist. There are two problems with this argument. First is that there is no significant difference between humans and other living thing’s impact on the environment. Second is that our policy towards endangered species is not actually a form of non-intervention.

Any species that covers huge swaths of the Earth in skyscrapers, pumps noxious gas into the air, litters the earth with their non-biodegradable waste, and leaks deadly chemicals into the ocean is clearly significantly different from the rest of harmonious life on earth, right? I am talking, of course, about Ordovician Algae and the first trees that followed them. For the first few billion years of Earth’s history, all life was in the oceans. As the first species of algae climbed up onto barren rocks, they began a series of massive environmental changes that would become the Ordovician mass extinction. The land algae sucked phosphorous out of their accommodating rocks and dumped it into the oceans. This caused algal blooms which sucked so much oxygen out of the ocean that it suffocated most of marine life. A few million years after the pioneering algae, the surface of the Earth was dominated by giant wooden skyscrapers: trees. These plant factories radically changed the world’s air chemistry. Additionally, their wooden bodies were impossible for any bacteria to decompose, so their dead piled up until a lighting strike lit them on fire and caused continent scale forest fires, pumping smoke and carbon dioxide into the atmosphere.

The purpose of this example is not to demean algae or trees but rather to point out that human beings are not unique in their ability to radically change the environment at the expense of many other forms of life. Many forms of life build cities, create waste, and output chemical pollution. Since we are just as much life as they are, and our actions aren’t so different, why should we wish to prevent our impact but not theirs?

Even if you do think that human impact on the environment should be avoided, the way we protect endangered species is not good practice of non-intervention. The example of the Desert Tortoise is again useful. As part of BrightSource’s required steps to avoid killing any tortoises, they built holding pens to house hundreds of tortoises for months.

Wildlife officials are still unsure if they will release the animals [from the pens] this spring because a drought is expected this summer. Last October, a tagged female, BS-71, had been in a holding pen for four months and wasn’t adapting. She endlessly paced her enclosure. Over and over the animal attempted to climb the wire mesh, gaining some height, then usually ending up flipping on her back. Unable to bear the sight of the tortoise’s apparent distress any longer, BrightSource lead biologist Mercy Vaughn sought permission to release the female to the wild. The request has since been dubbed the “Mercy Rule.” After gaining approval from the U.S. Fish and Wildlife Service, filling out paperwork, providing medical testing — a tortoise under stress is more susceptible to disease — Vaughn was finally cleared to free the homesick tortoise.

This is not leaving the natural world on its own terms, it is extreme meddling to pursue a purely human goal. This is common across endangered species efforts. Animals are captured, tracked, hunted, and bred by human conservationists. Human interests pick some species as endangered and some as invasive. They protect one and exterminate the other. If avoiding human impact on the environment is our goal, this is not the way to do it.

Inherent Value of Biodiversity

No one can deny that the Desert Tortoise and all of its fuzzy, feathery, or fish friends are beautiful and interesting and symbols of the miracle of life. Shouldn’t we strive to preserve the maximum diversity of life out of respect and admiration for this miracle? This argument is intuitive and emotionally appealing, but even accepting the inherent value of biodiversity does little to justify our current paradigm of policing endangered and invasive species.

First, quantifying this value is very difficult. We know how much people are willing to pay in entrance fees to zoos and natural history museums, and we know how much people donate to the WWF to save Pandas. These voluntary exchanges are above reproach, but most of the costs our society incurs in service of endangered species come from coerced tax payments and regulations that businesses are forced to follow. Is the existence of some Desert Tortoises worth stealing $200 million dollars or preventing the growth of renewable energy?

More important than the practical challenges of valuing biodiversity is the fact that protecting endangered species and preventing the growth of invasive species has no clear impact on biodiversity in anything but the immediate short term. It is obvious that if the Desert Tortoise goes extinct tomorrow, the earth will have one less species on it’s surface that day, but in the long term, extinction is the fuel for the biodiversity of the future.

Billions of species have been born and gone extinct over the natural history of Earth. There have been several massive extinction events which wiped out up to 75% of the planet’s species. There was never any protection for endangered species and invasive species were free to compete anywhere. Still, the arc of biodiversity trends upwards. The asteroid that devastated the dinosaurs opened the door for an explosion of biodiversity in mammals, eventually including homo-sapiens, would we go back in time and try to prevent those extinctions? If not, why should today be any different? Some species will thrive at the expense of others, habitats will drastically change, new forms of life will emerge. This is the natural course of life. In fact, extinction is a necessary tool of evolution. Without extinction, selection, and competition there would be no biodiversity and we might all still be trilobites at the bottom of the ocean. If the Desert Tortoise cannot survive then let it die and be replaced with the Desert Lizard or the Desert Hare or whatever else will rise up to take advantage of the niche that it left unfilled.

Instrumental Value of Biodiversity

The final argument for protecting endangered species and policing invasive ones is that this practice furthers human aims by keeping food chains stable.

Stability in the human food chain is extremely important. Literally everyone needs it to live. If some species that is essential to our ability to cheaply produce food is endangered by any force, human or natural, it is a cause for concern and a justification for action. One example you might remember from the news cycle is honeybees. If their populations collapsed, our crops would have a much harder time pollinating and growing, restricting output of food. Despite years of media alarmism, this was never really a risk, but the hypothetical scenario is possible. The problem with this story is that almost none of the over 2,000 endangered species have any importance to human food chains. Even though extinctions can have domino effects that ripple across ecosystems, extinctions of these species are unlikely to be impactful. This is due to inherent properties of endangered species and specific properties of our modern food chain. Endangered species have, by definition, small populations and habitats. Given this, it would be difficult for one of these species to have a large effect on the whole of the ecosystem. They are small and dwindling sources of food so few other species would rely on them for sustenance. Therefore, few other species would be affected by their extinction. Additionally, human food chains are very insulated from what happens in the larger ecosystem. Even if the butterfly effect means that a Desert Tortoise extinction can have impacts on Snow Leopard populations, if it doesn’t affect cows or chickens or corn, it won’t impact us much.

This property of human food chains provides an example of a much more promising strategy for protecting our food supply from changes in the environment. Rather than relying on and attempting to preserve stability in the extinction and speciation rates in the environment, we should instead try to separate our food chain from the ebbs and flows of the large ecosystem as much as possible. Since our switch from hunting to farming we have come far along this path. Further developments in genetically modified crops and lab grown meat are promising ways to secure our food supply against even large extinction events in the outside ecosystem.


Like almost everyone, I love animals. I watch nature documentaries and marvel at the diversity and beauty that arise out of the simple optimizing rules of life. There is value in preserving parts of the earth for nature and there is value in biodiversity. This value can be captured and charged for in nature preserves and national parks. The beauty of nature does not imply that there is value in protecting a long list of certain species that happened to be around at the same time as us, however. Extinction of species that are maladapted to their environment is necessary for a well functioning ecosystem, even when our influence is a guiding force in that ecosystem. Clinging to arbitrary branches of life is missing the forest for the trees. We shouldn’t let short term fixation prevent us from building a better world and letting the circle of life go on.