Last class we talked a lot about human impact on biodiversity and we sort of came to the conclusion that biodiversity is a good thing because it offers a myriad of ways to support humans. Species richness can provide medicinal benefits for humans, recreation (ie. hunting and fishing), food, cloth material, aesthetic appeal, domestication (for farming, pets, and houseplants), and more. Not to mention, preserving biodiversity can stave off guilty feelings that accompany human implication in species extinction. But at the top of a mountain, where none of these species were being actively used by humans, what was the big deal if some plants got trampled? According to the laws (I guess technically theories) of evolution, if foot-trails damage species diversity or change the composition of the soil, natural selection would (over a long, long, long time) give way to modified species of what is there now that could withstand impoundment by high traffic hikers or could survive the changing composition of the soil.
This was something I struggled with in my high school environmental science class; I would be able to answer any question with "this is bad because it results in the loss of biodiversity," but when asked why the loss of biodiversity was bad, I was lost for words.
So, I did some thinking.
There are a lot of benefits to biodiversity, like boosting ecosystem productivity (which, of course, is related back to anthropocentric things like farming) and providing economic, biological, and social services and resources. But the most important one, I think, are its implications for the gene pool. Biodiversity essentially means that many, many species are sharing a environment and when many species share an environment, it means that there is incredible genetic variation within that environment. And with genetic variation comes the incredible effect of a buffer system. So when the ecosystem is disrupted by, say, a large-scale parasite, representatives of only a few species will be really negatively affected. And should that parasite achieve almost total-wiping-out of a species, it is more likely that some organisms will be spared because of some genetic abnormality. If that parasite remains a constant threat to the environment, then the surviving organisms can essentially produce a new subspecies that is resistant to the threats of that parasite. Granted, this would take an exceptionally long period of time, but that's how natural selection works. And if every member of a single population (meaning one species in one area) had the exact same genetic material, then they would all be susceptible to any major ecological disruption. After all, evolution only works when there's genetic material to work with. So the presence of genetic variation (due to a diverse community) is what allows an ecosystem to survive widespread damage--biodiversity is a good thing because it enables communities to survive the planet's natural cycles.
Ultimately, stomping on rare alpine species doesn't directly matter to humans--we're not using those organisms for anything--but it does have an incredible effect on the ecosystem at large. When we kill the things under our feet, we reduce the biodiversity of the land and therefore the genetic variability. And once we do that, we make the communities that live there much more susceptible to being wiped out--whether that's by anthropomorphic or natural causes. When those populations are gone, the ecosystem's capacity to perform important ecological services, like water drainage, air purification, nutrient cycling, etc., is severely undermined. This is still an extremely human-centered understanding since we are definitely included in the organisms who benefit from those ecological services (and we appreciate the beauty that biodiverse landscapes provide), but it's hard to think of it any other way--if I don't relate these abstract ecological concepts back to humans, then they don't seem anchored or relevant, but of course that's just the way I've been taught to think. At any rate, it seems obvious to me that preserving species diversity is an incredibly important thing, if only because it seems unfair that humans are allowed to dictate which species survive or at least have a better chance of surviving.
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Articles I recommend:
http://www.globalissues.org/article/170/why-is-biodiversity-important-who-cares
http://www.scientificamerican.com/article/what-is-the-point-in-pres/
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