Inheritors of the Earth: Book Review
Conservationists have frequently fallen out in disagreement over the best way to look after species, habitats, and the biosphere as a whole. The FaBio research group recently sat down to discuss Chris D. Thomas’ book ‘Inheritors of the Earth: how nature is thriving in an age of extinction’. Focusing on the chapter ‘Heirs to the world’. Here, we present our discussion making note of any interesting points that the book raised as well as rebutting those we disagreed with. While we may disagree in places, Thomas’ ideas provoked a full discussion on, in essence, “What is the goal of conservation?”.
To summarise, the chapter focuses on the plight of the Takahe, a flightless bird from New Zealand. The Takahe was once thought to be extinct but was rediscovered and ‘saved’ from the novel predators of rats and stoats by moving individuals onto offshore Islands which had been cleared of the invading mammals. Without this work, it is likely that the species would have gone extinct. However, this has not prevented the extinction of the Takahe indefinitely. Rats are able to swim the short distance to the island sanctuaries so must be constantly monitored and exterminated. This is not, as Thomas puts it, a stable ecosystem. Conservationists have set themselves up for a fight that will never end.
Should we, therefore, assign the flightless birds of New Zealand as a failed line of evolution? A design of species that was perfect for living on an isolated predator-free island but is now unable to survive. Thomas’ ideas put forward the notion that humans did not cause the extinction of these evolutionary oddities, but rather hastened their demise and our continued effort to provide life support for those that remain is only postponing the inevitable. The world is constantly changing and will never be prevented from doing so. Why not back the creatures that are successful rather than perpetually holding a rolling rock on the side of a hill?
There is, however, another option. Thomas argues that we should stop forcing nature back towards some pre-existing ideal vision but rather start guiding nature towards a stable robust equilibrium. Pointing out that, on the island sanctuaries, the Takahe’s favourite food is the non-native lawn grass outside the visitor centre. Not all changes to New Zealand’s fauna have been detrimental to the Takahe. The islands themselves have never been inhabited by Takahe anyway and if we can move them to novel environments, that will never be reverted to their pre-human era, why not go further and spread the Takahe to a range of islands that will remain predator-free with much less effort, say in the Pacific.
This is the point of Thomas’ book. The world is changing, it has always been changing, and it is futile to prevent it. Why are we not discussing the success of rodents or plants which have managed to spread across the world? This is the stage that opened our discussion.
Noted by many at the table these ideas can be antagonizing. Suggesting we should allow a species to go extinct can become personal if a person or culture has a specific fondness for the species in question (The Kakapo was mention repeatedly). However, a similar case was raised by a colleague who brought forward his year-long personal battle about the status and preservation of the Scottish Wild Cat. The Scottish Wild Cat is not at a stable equilibrium, it is possible that no ‘pure’ individuals even exist in the wild. The cause of its decline cannot be removed. Conservationists could discuss and, in theory, wildly plan to exterminate all non-native mammals from New Zealand. But, suggesting that the feral cats of Scotland and their source, household pets, be removed from the British Isles is unlikely to gain much traction.
These examples are, however, extremes. There is a world of difference between the success of rodents and the decline of the Kakapo. The majority of animals and plants will lie somewhere in the middle. Here we find our biggest fault with the text, despite the divisive arguments that point us in a certain direction, Thomas seems to hold back in places. Mentioning on one page that the preservation of flightless New Zealand birds is futile but stating on the next how important it is to “protect different kinds of habitats that exist in the world, especially in places where there are concentrations of species that live nowhere else”.
We felt the book should have headed towards a manifesto, stating the way forward for conservation. Whether that direction is correct is up for debate, but Thomas holds back from giving any concrete suggestions.
What is the end goal of conservation? Do we want a stable community, or a productive one, or the one with the highest biodiversity? There are further questions, outside of conservation, that should be asked about a species before we condemn it. Are there any cultural reasons people may wish to preserve a species. This goes beyond that of the white colonist perspective of guilt about causing the factors that lead to their demise. But also, ethnic and minority groups that may view the species as essential to their culture. Furthermore, what if the species has been a flagship for conserving a whole ecosystem, for example, the orangutan and the Bornean rainforest. It has been frequently proven that conservationists do not always know what they are doing. However, one of the outright successes has been the removal of non-native predators from island ecosystems.
Ultimately, we need to decide the end goal of conservation. While we understand and agree with Thomas that conservationists should pick their battles, we do not agree that we should abandon species if constant efforts are required to stave off extinction. To us, this is akin to arguing against washing yourself, based on the fact that you would only get dirty again. Even if a stable ecosystem cannot be reached, then the goal of maintenance can still be worthwhile. Sea-bird breeding sites in South Georgia must be frequently monitored for the presence of rats, but does it make previous efforts at eradication pointless? We would say no.
There is no undo on extinction. There are many species that would be already extinct if we had accepted them as maladapted to the modern world and beyond hope. We are, as of yet, unconvinced about pulling the plug on the Takahe.
Dr Regan Early