Today I want to talk about a little-recognized fact about biodiversity. When most people (myself included) think about what the value of biodiversity is, they likely conjure up some image of a multicoloured meadow, or of songbirds singing in the woods — in other words, they might struggle to put their finger on any extrinsic value of biodiversity beyond vague aesthetic/moralistic sentiments (this is how I felt, at least). But more recently, I've learned that there are actually some very compelling positive properties of biodiversity, besides being pretty.
Turns out there have been a whole bunch of interesting studies comparing monocultures and more diverse ecosystems, and they've all drawn more or less the same conclusion: more diversity = more productivity. To name a few examples: fisheries with higher species diversity have higher yields; greater diversity of tree types increases overall wood production; and greater diversity of plant species makes plants more resilient against diseases. This last property of biodiversity, I think, is the most intriguing. It means that not only are organisms slightly better-off in diverse ecosystems, but that they're much less likely to get wiped out entirely. Which is a big deal.
This unfortunate property of monocultures — that they have very little resistance to disease — has had at least one very significant impact on world history, namely, the Irish Potato Famine of 1848. For those of you who aren't familiar, I'll give a quick summary: basically, the potato crops failed in 1848 throughout Europe, due to a nasty little protist that rotted the potatoes from the inside out. Due to an unhappy combination of circumstances, the vast majority of the Irish population at that time was entirely dependent on potatoes as their only food crop; and not just potatoes, but a single strain of potato. This strain was delicious and nutritious (I assume), but unfortunately wasn't so great at fighting off blight. In one year, Ireland lost 20% of its population. A million, roughly 12%, died of starvation, and another 8% emigrated (including many to Canada, my great-great grandparents among them). The famine left a huge scar on Ireland, and even today, its population has not recovered to pre-1848 levels.
So we should know what we're dealing with when we talk about biodiversity. It's not some subtle, aesthetically-motivated cause after all. Biodiversity is key, and it's probably the only way life has been as resilient as it has been on this planet to date.
I could end this post here, and I do hate to be so anthropocentric, but I just can't resist the analogy with human culture. I think the human race (being a biological system in its own right), owes a lot to its diversity, just like the rest of nature. I think cultural diversity is something we all, to some extent, have trouble accepting. After all, what's harder to accept than something different? But I also think it is the most fantastic aspect of humanity. Just like in nature, diversity lets us achieve more than we ever could have as a monoculture — in the arts, sciences, you name it; and just like in nature, diversity makes us resilient: just as one great civilization is collapsing, another is awakening somewhere else. I could go further, but I'll leave off here, as the relevance of this to environmentalism is already somewhat tenuous. Just thought that was an interesting analogy.