Are exotic aliens species less important than “natives or indigenous” species?

A view  that engenders heated debate and angry responses from ecologists and conservationists is questioned by Yolanda van Heezik,  in an essay on the Nature of CIties. Although this essay adreeeses the topic of exotic versus local fauna, it is equally valid when considering vegetation.

“This emphasis on killing introduced species to protect native ones makes me wonder how much people involved in these activities think about why they are willing to kill some to protect others. Why do they value native species above others?”

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From the Department of Conservation’s blog which provides step-by-step instructions on how to trap in your backyard: https://blog.doc.govt.nz/2017/10/15/how-to-trap-in-your-backyard/

Endemic faunas and floras make a country unique, and it is that uniqueness that engenders among its human inhabitants a sense of place or identity. Those species with populations that respond best to predator control are the most deeply endemic ones; in New Zealand they are species that have evolved for millions of years in an environment with no mammalian predators. The only terrestrial mammalian species native to New Zealand are a couple of species of rather small, insectivorous bats. When urban residents band together to trap rats or possums, it is to protect these vulnerable, endemic, native species — they want to be able to share their living spaces with them and encounter them as part of their day-to-day lives, rather than having to travel to special predator-free areas such as offshore islands to see them. NZ’s Department of Conservation’s Threatened Species Ambassador, Nicola Toki, argues that native species and introduced predators in New Zealand cannot co-exist, and that it is the indigenous subset of our biodiversity that fundamentally defines us as a nation.

This emphasis on killing introduced species to protect native ones makes me wonder how much people involved in these activities actually think about why they are willing to kill some to protect others, i.e., why they value native species above others? There has been long-standing, ongoing debate in the scientific literature on how introduced species should be managed, with some scientists arguing that the paradigm of native/non-native is no longer relevant in highly modified environments, such as urban landscapes (Davis 2011). Instead, proponents of this school of thought assert that environmental management should involve acceptance of alien species and novel ecosystems. Conciliation ecology is thought by some to be the morally acceptable course of action (references in Russell & Blackburn 2017), but is soundly rejected by others.

While there is no doubt in New Zealand that the introduction of predatory mammals into a fauna that evolved without any mammalian predator has had a disastrous impact on many of NZ’s native species, not everyone in NZ agrees with Nicola Toki’s sentiments or the concept of valuing native species above others. For example, one opponent to the “predator-free” concept asserts that “we can’t keep erasing the fact that the species that we introduced, whether managed or not, are ‘ours’ too — even the ones we later decided were a mistake. They’re our responsibility as well. And a future where people learn to accept the presence of our introduced species is not so horrifying.”

This view is being echoed more frequently in the media; in a recent opinionpiece in The Press, columnist Joe Bennett writes:

“We like our birds here. They’re our signature fauna. No-one else has got them and we haven’t got much else. But among birds we practise apartheid. We distinguish between birds that are — and here’s an adjective that chinks like a gold coin — native, and those that are not. Native birds are first-class citizens who can do no wrong. The rest are the rest and the magpie is among them. It’s an Australian import, loud, boorish, a bird to deride.”

At a more general level, in other countries, criticism has been leveled by social scientists at those advocating for native species, labelling it as a form of anti-immigrant nativism. They claim that the removal of non-natives reflects an anti-immigrant, racist, political discourse (Mastnak et al. 2014). They draw our attention to the Nazi policy of removing non-native plants, and by doing so implicitly associate the protection of native species with Nazism. An alternative perspective is that many current ecological problems are a legacy of colonialism, a process of settlement of plants, animals and people that resulted in the uprooting of native plants and indigenous peoples (Mastnak et al. 2014). This was certainly the case in New Zealand, where we even had an “Acclimatization Society” whose role was to introduce many species from the UK, where most settlers originated from, and create landscapes populated by familiar species. After early waves of extinctions this process was thought to be a means of restoring biodiversity to a depleted environment. Advocating for native plantings then becomes a process of decolonisation, which is ethically appropriate.

Others advocate for the middle-ground; they both question the dichotomy between native and non-native, but at the same time acknowledge that low-impact, non-native species should be tolerated, and that control methods to remove alien pest species can also be contentious if they involve the use of toxins (Shackelford et al. 2011). Some critics have raised the issue of involving children in the process of systematically killing predators, but also the militaristic dimensions of the entire exercise, which uses terminology such as “war on predators”, or “under siege”, and what some consider to be xenophobic expressions (Schlaepfer et al. 2010 ). Simberloff (2003) discusses the claims and suggests that it is impossible to prove that aesthetic preferences for native species are infected by nativism or xenophobia. He points out that those who criticise efforts to control non-native pest species often ignore their ecological and economic impacts, which alone comprise a valid, ethical rationale for managing introduced species.

Read the full essay

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