Our Responsibility Regarding Invasive Species (A Counterpoint to Mark Davis)

The Eastern Oyster, a species which has a high potential to spread throughout Norwegian waters, but little known ecological effect (Image Credit: James St. John, CC BY 2.0, Image Cropped)

Last week I posted an interview with Mark Davis, an invasion ecologist who has urged caution when rushing to eliminate invasive species from an ecosystem. Whilst I didn’t agree with absolutely everything Mark said, he makes some very important points about the language around invasive species and our understanding of them.

Posting the interview in an online forum (let’s not try and make it sound sophisticated, it was Reddit) prompted a response from a user which I thought was interesting, and warranted further discussion. I want to stress that during this piece I will only be using excerpts, however you can find the full response¬†here.

The issue is not one of human values; the issue is that, owing to anthropogenic activities, the environment is changing at accelerating rates that critical species and processes can’t survive, leading to irreversible changes. The ever increasing burden of invasive species is a part of that dangerous situation.

I don’t necessarily disagree with all of this. The issue is indeed that anthropogenic activities are driving certain species into new areas; I’ve written about that before. But I think there is a difference between preventing translocation and seeking to eradicate a non-native species for the sake of nativism. Invaders certainly need to be controlled if they threaten locals with extinction, and we should certainly discourage the introduction of new species. But focusing on wiping out local non-native species if they pose no threat seems pointless. And yet…

Just because you cannot see the impacts of an invasive species on a few sympatric species in your size- and time-biased samples does not mean that the species is not problematic at smaller or larger scales, spatially, temporally or ecologically.

This is an important point, and it’s why invasion ecology is so important: we need to be able to predict how a species will impact an environment early on and take adequate measures. Often, a species’ full impact will not be known until it is well-established, and it is more often than not impossible to eradicate a species at that stage. So the study of alien species, both invasive and non-native, is crucial, and will hopefully mean in the future that we can decide which species are worth controlling for the sake of ecosystem protection and not for the sake of ‘the good old days’.


The Garden Lupin, an invasive plant capable of homogenising huge sections of grassland (Image Credit: pxhere, CC0 1.0)

We will never restore pristine wilderness (that, to me, is something of a straw-man argument, since conservation never has and probably never will have the resources and cultural support to achieve that end), but I am of the opinion that we must try anything and everything at our disposal to preserve long-established (i.e. native) systems and slow ecological changes – whether they come from climate, pollution, species invasions, etc. – so that more ecosystem processes have time to adapt.

I agree with this. I agree that we should be preventing anthropogenic change of ecosystems. I agree that we should prevent the introduction of new species into areas, for the sake of precaution. However I don’t think that the preservation of long established ecosystems should include the eradication of any new species which pop up. And it’s true that ecologists have never had the resources to restore pristine wilderness, which is why prioritisation of management efforts are so crucial, and the elimination of species we don’t know to be harmful is potentially wasteful.

I don’t agree with everything that Mark said either. I think there are instances where we have a responsibility to ensure the survival of a native species, and if that includes eradicating an invader which is doing it harm, so be it. But I don’t think that targeting any non-native species on the basis of their origins is helpful.

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