On a morning run I came across a sign in the park informing me that the city was “helping nature by controlling invasive plants.” This help involves herbicides and machetes as my adopted city of Tallahassee is quite active in addressing invasive species. Laying aside concerns about herbicides; this raises philosophical issues.
On the one hand, the phrase “helping nature” can be dismissed as a rhetorical device. It presents the destruction of invasive species as a benign act and might be intended to offset negative feelings about use of herbicides. As you smell chemicals and feel your skin and mouth itch a bit, you will know that this for the good of nature. On the other hand, it does imply a value position on what helps nature. I’ll look at this notion.
Taken at face value, sign implies invasive species harm nature and thus it is good for us to kill them. But these is the obvious concern that invasive species are also part of nature. For example, feral hogs, Burmese pythons, and Nandina are natural beings and they are, one would assume, not helped by being killed by us.
One way to address the ethical concerns is by using a utilitarian argument: allowing invasive species to thrive will do more harm to the ecosystem and its inhabitants than killing the invaders. As such, killing invasive species is the right thing to do in such cases. This approach would allow for invasive species to be left alone if their presence created more good than harm for the ecosystem. Whatever that might mean.
While this seems reasonable it suffers from an obvious practical challenge of making a rational and informed calculation of what is likely to be best for nature. Humans have generally proven bad at this, so such assessments need to be critically evaluated.
Another counter to the idea that we should “help nature” is that it is natural for species to migrate to new areas. Animals are usually mobile and have spread around the world. Plants have spread far and wide, such as when seeds are transported by birds. If life originated in one or a few locations, this has been going on since the beginning. And it continues to this day; the natural world is not static, and species are constantly on the move.
I am not arguing that this feature of nature is “good” because it has always been (that would be a fallacy). Rather, the point is that species moving is natural and interfering with it does not seem to really “help nature.”
Yet another counter to “helping nature” is to note that the idea of helping nature suggests nature has a purpose, goal, or end that we can assist with. The idea of nature having an end is well known in philosophy, although it is generally rejected these days.
Aristotle famously claimed that all natural beings have ends, thus arguing for a teleological reality. To use a simple example, an acorn has the purpose, goal, or end of becoming an oak tree. If one looks at nature in teleological terms, then we could help nature by assisting it in achieving its purpose. This matter can get complicated if natural being have competing ends (which they usually do), but it could make sense to help or harm nature if one holds to a teleological view. There is also the religious option.
One could embrace a religious view that grounds a teleological view of the natural world. One could accept a goddess of nature and help nature by helping her achieve her ends. Or one could accept the existence of God and help God by assisting the natural world achieve God’s ends. One would just need to sort out what the deity wanted in terms of help. As some might find supernatural things problematic, they could rely on human values.
If we accepted a teleological view of nature, then we can argue that we should deal with the invasive species we introduced by accident or design. These would include creatures such as cane toads, rats, mussels, and various plants. We are accountable for our actions, perhaps even when they are unintentional. One could even argue that what we do is artificial rather than natural, hence we need to undo the unnatural things we have done. Interestingly, this seems to entail we are the most invasive species and we should restore ourselves to our original habitat and return the world to some earlier time of species distribution. Interestingly, this does make this sort of conservation analogous to the conservative world view in politics: a desire to restore the world to some preferred (usually imagined) past. The obvious problem, given all the change, is deciding which time defines the “correct” past state of things. This leads us to human values.
Species tend to be condemned as invasive based on their impact on human beings. For example, we North Americans do not usually label our dogs as an invasive species. This is not because our dogs are original inhabitants of North America, but because we like dogs. Recently arriving species generally get labeled as invasive when we do not like what they are doing. For example, Floridians generally do not like the non-native species that are overrunning bodies of water in the state. This is because of the impact they have on us. This is analogous to how people look at the migration of other people: people are fine with other people they like coming here. But they get very angry when the people they think should not be here come here. And, of course, they slap negative labels on them and argue for their removal. But let us get back to non-human species.
Since humans matter morally, I think we have the right to consider the impact of species on our well-being. But we should be honest when we do this: we should not claim that we are helping nature, we should acknowledge that we are doing what we think will benefit us. This is something to be addressed in ethics, sorting out what is right based on the correct moral theory (if there is one).
Being a self-interested human, I agree with some efforts to address species we call invasive. For example, the park near my house is infested with tung trees. These trees were introduced to the United States intentionally to produce tung oil. This industry failed, but the trees spread throughout Florida. I dislike the trees because every part of the tree is poisonous. The leaves can cause a reaction like poison ivy and a single seed can be a fatal dose of poison. I recognize they are as much a part of nature as I am and hence do not argue that they should be removed because they are not native. Rather, I am fine with their removal for the same reason I would be fine with removing broken glass from the park: they are a hazard.
To close, merely being invasive does not warrant the removal or destruction of a species. Otherwise, we would need to be removed or destroyed. Rather, this is a matter for moral (and practical) assessment. Talking about “nature” and labeling species as “invasive” is mostly a matter of rhetoric and we would be better off being honest about what we are doing and why.