Biodiversity is just what it sounds like: diversity of living organisms. In general, we tend to think that diversity is a good thing. The variation among living organisms is breathtaking. It makes sense that we would try to preserve it. Imagine a world in which all the trees were the same kind, all the dogs were the same kind, all the flowers were just one single kind. BO-RING.
Besides being awesome to observe and study, biodiversity also helps species by giving them many different types of other organisms to interact with, thus honing their fitness. Think of a runner training for the Olympics 200 m dash. If she only practiced by running 200 m on a track over and over, she would have little chance of winning because her muscles would only be given one type of challenge. Instead, she will do all sorts of exercises and training regimens to strengthen her heart, lungs, and all of the muscles in her legs. When species interact with each other, they compete for resources and put pressure on each other to survive.
Cheetahs are only the fastest animals in the world because, gradually over time, the slower cheetahs died off, probably because they couldn't run fast enough to kill enough food to survive and reproduce well; they couldn't hack it with the big boys. Biodiversity is like Olympic training for the evolution of species.
For most of the history of the Earth, biodiversity just followed its own course. Species interacted and competed with each other and the environment. Some became extinct, others went on to thrive, and still others came into being. For most of the history of human beings on Earth, biodiversity continued to follow its own course. But we're a powerful species. We can alter the land and oceans, and mess up other species' habitats, very rapidly and quite drastically. Habitat destruction, overhunting, and overfishing have caused many species to go extinct.
On the up side, we know how to use our technology to track species and study them and their habitats in ways that were never before possible. We are also learning ways to use the resources of the Earth (through mining, agriculture, etc.) in ways that do as little damage as possible. Whether or not we use this knowledge is another question.
In 1973, Congress passed the Endangered Species Act (ESA) in order to protect species from going extinct and "encourage" businesses to choose environmentally friendly options. The US Fish and Wildlife Service (FWS) maintains the official list of endangered species. The law has several consequences. Probably the most infamous one is that businesses must apply for permits from the Environmental Protection Agency before they build anything. They must check the land and verify that their building will not harm any endangered species. This is where science meets policy.
An endangered species is one that "is in danger of extinction through all or a significant portion of its range." (A species' range is all of the territory where it lives.) It's a tricky thing to determine that a species is endangered. 5,000 water buffalo is a very different number from 5,000 mosquitoes. That brings up another point. The FWS doesn't give priority to higher forms of life. You might think it would be just fine if mosquitoes went extinct but the FWS will protect them just the same.
What are most commonly reported in the news are stories about a human endeavor harming the habitat of an endangered species. For example, in Pacifica, CA, there is a golf course that the Wild Equity Institute is suing to shut down because they claim that the lawn watering and mowing are harming the San Francisco garter snake and the California red-legged frog, both of which are endangered species. Snakes and frogs can't vote no matter how much you might like them. Would you like to be the politician that works to take away your constituents golf course?
Ironically, the ESA can even pit one species against another. That's what's happening in litigation over species that inhabit the Bonneville Dam, which is on the Columbia River located along the border between Oregon and Washington. There are two endangered species of fish (salmon and rainbow trout) that travel along the river each year to reach the Pacific Ocean after spawning inland in freshwater. A population of California sea lions (not an endangered species) preys on the fish as they work their way through the Bonneville Dam system. In order to help the endangered fish, the National Marine Fisheries Service has been authorized to remove (and kill) 92 sea lions each year through 2016. The Humane Society challenged this and a judge has reduced the number from 92 to 30. The policy question that this raises, of course, is what efforts are legitimate in helping endangered species to survive? Where do we find the balance between helping one species and hurting another? Do we know enough to be able to decide how many predators are sufficient to keep a species "on its toes" evolutionarily but not sufficient to drive it to extinction?
Finally, our desire to protect habitats for endangered species can also conflict with our desire to find more environmentally friendly ways of obtaining energy. Solar energy is an up-and-coming renewable source of energy. Obviously deserts are a great place to put solar panels because of the intense sunlight that they receive. Plus, there aren't many people living in the desert to complain about the unsightly panels blocking their views of nature. But what if the panels will interrupt the habitat of an endangered species? That is what's at issue in lawsuits that seek to require the inclusion of a desert tortoise on the endangered species list- so that further interruption of their habitat would be forbidden. The litigation has already limited solar development in the Mojave Desert in California and seeks to do the same in the Sonoran Desert in Arizona.
Stories like these show us that science cannot direct policy decisions on its own. Science can help us to determine what species need in order to thrive. Then we must make value judgments and do the best we can after weighing the importance of many different issues. How would you rank the following good things? Would your rankings depend on specific scenarios?
a) Biodiversity, b) Environmental protection, c) Increasing your country's energy production, d) Increasing renewable energy production, e) Increasing jobs and helping the economy.