Mea Culpa, the article is titled "What is Nature Worth?", not "The Value of Nature". It says some very interesting things, mainly supporting the notion that intact ecosystems around the world are economically more valuable than the space they use, and thus that "humankind" should invest intellectual and real capital in preserving Nature for that reason, as well as on moral grounds. It is an intriguing and potent argument for conservation, in my opinion, but unfortunately human beings have not shown a propensity thus far in our history for the sort of long-term investment it would require. We are not able to properly analyze the costs and benefits of the situation, because we tend to discount the costs of environment degradation, and ignore the benefits of conservation. Just as an example, photosynthesis by creatures all over the planet, and the accompanying carbon fixation from CO2 represents a huge, free benefit that Nature provides us. We ignore it, however, because it is invisible. While we are in no danger of destroying all plant life on the planet, we could lessen the burden on ourselves for cleanup of pollutants, if we simply maintained open, wild space to a greater degree. Anyway, read the article, if you can, I don't do it justice.