The people over at ScienceBlogs have a feature called, "Ask a Science Blogger". This feature poses a weekly question to the scientists hosting their blog on the ScienceBlogs site. In some cases the questions are submitted by readers, submit your question here. Some or all of the members then post their response on their respective blogs. You can view the full archive here.
In July, a particularly interesting question was posed that I would like to answer - Is every species of living thing on the planet equally deserving of protection? Lots of different potential answers come to mind - yes, no, everything except for mosquitoes, etc. After deep consideration, I have come to the conclusion that no, not every species is equally deserving of protection. I will explain my rationale here.
First of all, my personal value around species preservation deals with natural ecosystems. I believe that the best chance that all life has on this planet, including human life, occurs in the presence of strong, natural, balanced ecosystems. These balanced ecosystems help to maintain healthy and ever evolving populations of species. The absence of critical ecosystem participants causes the natural balance to be disrupted. This lack of balance usually allows some species to over populate, providing unfair advantage over other species. The disadvantaged species are reduced or eliminated, causing a further cascade through the ecosystem. While the over-populated species have a short term advantage, they quickly suffer from their own success. By eliminating or at least decreasing their food source, many will starve, but more importantly, the chance for further evolutionary species growth will be inhibited (my personal theory, I have not read any studies to this effect). This limitation in further evolutionary growth can mean the end of that species. This results in further cascades through the ecosystem. The elimination of a minor species from a balanced ecosystem can set off a chain of events resulting in a complete collapse of species diversity.
In evolving research, it is becoming apparent that the elimination of wolves in Yellowstone in the early 1900 allowed the elk population to grow uncontrolled. The elk quickly ate the willows and cottonwoods growing near the rivers. The reduction of willow and cottonwood trees caused a dramatic reduction of beaver colonies. The lack of beaver colonies reduced the habitat for native trout species. The chain goes on. The over populated elk also contracted diseases which were spread by sick animals which would survive longer in the absence of wolves, spreading the disease to more elk. The elimination of wolves also allowed the coyote population to grow uncontrolled as wolves and coyotes compete for territory. The over population of coyotes resulted in the reduction of ground squirrels and other food sources. The coyote population then became diseased as well, with a pup survival rate of less than 10%. All of these changes, and many more, were the result of the elimination of a single species - the wolf.
On the contrary, evolution occasionally produces dead end species. Species have regularly gone extinct over the history of life on this planet. I do not believe that these species should be preserved beyond their natural existence. Thus, the real challenge is for humans to determine which species are being threatened by our own over-population and which species are being threatened by purely natural processes. I don't have much confidence in our current ability to make these determinations.
In conclusion, I don't think all species are equally deserving of protection. Specifically we should not be protecting species which are being naturally removed from the ecosystem through evolutionary dead-ends. Since many more species are threatened than I believe are naturally evolutionary dead-ends, and we do not have the current ability to completely evaluate a single species role in a healthy ecosystem, I believe we should error on the side of over protection. In practice, this means that we should work to protect all species.