Rockström et al. (2009), in their survey on just how much shit (read: humans) this planet can take, ranked loss of biodiversity as the most severe of the effects humanity has on the natural world. As I mentioned in my definition of mass extinction post, one of the criteria is that the rate of extinction must surpass the natural background rate. And we’re succeeding wonderfully, according to Rockström et al. (2009), with extinction rates nowadays 2 to 3 orders of magnitudes above the regular rate.
I often get asked why this is important. It’s simple. Biodiversity is a catch-all term. In the classical sense, it just means number of species; nowadays, we view biodiversity at all levels, from the genetic, through the population and species level, ultimately to the habitat and ecosystem. These are all connected – but the fact remains that what we destroy are population and species.
This means that their genetic diversity is forever lost. That’s genetic diversity that might have helped a species pull through a future bottleneck. That’s genetic diversity that may have held the key to understanding the evolution and history of that population and species. That’s genetic diversity that, if it wasn’t lost, we could have harnessed for our own uses through domestication.
When you kill off a species or a population, you forever change the habitat and ecosystem it was living in. Plants and animals it may have preyed on now have less pressure on them and can grow more. Flowers they may have pollinated will have to hope they are generalised enough to attract other pollinators, or else they will go extinct as well. In other words, there are untold – and untellable – consequences of extinguishing populations and species.
And that’s just talking about effects with practical value. For the examples I named above, here are how biodiversity loss can affect us directly:
- A bottleneck can happen whenever a pathogen hits an agricultural plantation.
- Understanding the evolutionary history of a population and species is extremely important for a field like epidemiology – it’s how we can trace the origin of pathogenic viruses and bacteria, and knowing their evolutionary histories helps us design drugs that are effective even in case of mutation. None of this would be possible if we suddenly have a gap in the patogen’s evolutionary history, the gap being a vector or temporary host that we killed off and have no data for.
- Genetic diversity for domestication is obvious – it’s where we get the preferable traits.
- In the case of predators and herbivores, how would you like it if ladybirds went extinct and all your crops get eaten by aphids?
- Similarly, if bees are gone, we won’t reach our previous levels of agriculture, because while there are other pollinators, bees are by far the most productive.
- And for specialised flowers, for every specialised insect you kill, you can say goodbye to the orchid it pollinated.
Point is, loss of biodiversity isn’t just something hippies care about. It’s not just a love of nature and its beauty (although that is, for me and all other biologists I know, the number one factor). Loss of biodiversity has a tangible effect on you and your lifestyle. You may not feel it now. But neither does the lobster when he’s first put in the pot.
And it’s the same with every other environmental issue you might choose to ignore because “it’s a liberal conspiracy”/”it’s all made up by scientists so they can take our money”/”I don’t understand this, so it doesn’t exist”. And I say that statement purposely with a broad brush. There are no exceptions.
Rockström J, Steffen W, Noone K, Persson A, Chapin FS 3rd, Lambin EF, Lenton TM, Scheffer M, Folke C, Schellnhuber HJ, Nykvist B, de Wit CA, Hughes T, van der Leeuw S, Rodhe H, Sörlin S, Snyder PK, Costanza R, Svedin U, Falkenmark M, Karlberg L, Corell RW, Fabry VJ, Hansen J, Walker B, Liverman D, Richardson K, Crutzen P & Foley JA. 2009. A safe operating space for humanity. Nature 461, 472-475.