A challenge of biblical proportions
Amsterdam, September 7th, 2017
If you could be another animal for a while, which animal would you choose?
I would choose the... wait for it... I can blend into any environment with camouflage skills that surpass the chameleon’s, being able to change both the color and the shape of my body. I am an escape artist that outshines Houdini by squeezing myself through any hole larger than my beak. I never need to worry about carrying a pen, and I could easily star in an anime movie; imagine the possibilities with jet propulsion and eight tentacles that can finish a task if severed from the body. You may have guessed it by now, my choice would be the octopus. Dancing like birds of paradise, carpe diem like a mayfly, taking it easy like a sloth, or even having a bat day, there are still plenty of good options to choose from. Before I proceed with more serious matters, during the last months of finishing this letter I have felt like a Japanese puffer fish.1
I wrote to you because we are losing species at an alarming rate. Our amphibian friends are facing an extinction rate that could soon be over a thousand times the background extinction rate.2 This is remarkable, considering that this class of animals has been around since Pangaea, back when the continents stuck together. The background extinction rate refers to the rate at which species go extinct due to natural selection and is often expressed in extinctions per million species-years, because extinctions have been rather rare events during most of history. With roughly six thousand recorded amphibian species, and an estimate for the background extinction rate of 0.1 to 1 extinction per million species-years, one would expect about one amphibian extinction every sixteen hundred to hundred sixty years.3 Yet over the last thirty years the International Union for Conservation of Nature (IUCN) has recorded ten amphibian extinctions, including the fairytale like golden toad.
Survival of the fittest you may say, but the group of endangered species is not limited to slow and colorful toads. Many powerful, fast, and smart species have suffered significant population reductions during the last century; take for example the blue whale population that is “depleted by at least 70%, and possibly as much as 90%”, the tiger “population of mature individuals may be fewer than 2,500 individuals”, and the orangutan “decline of over 80% over the last 75 years” on Sumatra and “well over 50% during the last 60 years” on Borneo.4
The IUCN performs a census of the natural world by making population size estimates for both plant and animals species. These assessments are categorized with regard to estimated extinction risk and published as the IUCN Redlist. Currently, nearly one fifth of all assessed species is endangered with extinction, and one out of fourteen assessed species is critically endangered. Critically endangered species meet criteria such as a “population size estimated to number fewer than 50 mature individuals” or an estimated “probability of extinction in the wild [of] at least 50% within 10 years or three generations”.5
The attached infographic by Bill Marsh organizes the IUCN data by species type. The infographic depicts each hundred species assessed as an animal symbol, colored red for species that were classified as critically endangered, endangered or vulnerable. It shows that the threat of extinction is indeed widespread, and the bottom part reveals that there is also much we don’t know yet, as only a small percentage of species is assessed.
Table 1 presents IUCN data on the percentage of species that is affected by a type of threat within assessment categories. The ratio of species threatened by geological events to species threatened by human activities illustrates our role in the current wave of extinctions. Survival of the fittest it may still be, but we are to blame for the poor odds of survival for most endangered species.
According to Harvard emeritus professor E. O. Wilson – named Darwin’s natural heir in The Guardian – “half the species of plants and animals on Earth could be gone or at least fated for early extinction by the end of the century” if the current patterns of human destruction continue unchanged.6 Imagine telling your grandchildren about the thrill of swimming with whale sharks, or another animal encounter, and having to add that they can no longer see these animals in their natural habitat. I rather leave a different legacy and request your help to halt this worrisome trend of extinction.
I have tried to appeal to your heart, let me also appeal to your reason for as to why it is important to preserve biodiversity. Biodiversity makes ecosystems more efficient: “… as a general rule, reductions in the number of genes, species and functional groups of organisms reduce the efficiency by which whole communities capture biologically essential resources (nutrients, water, light, prey), and convert those resources into biomass.”7 – useful with an increasing number of mouths to feed – and biodiversity also makes ecosystems more stable: “Ecosystems that depend on a few or single species for critical functions are vulnerable to disturbances, such as disease, and at a greater risk of tipping into undesired states.”8 On top, preserving biodiversity gives a larger set of nature’s solutions and is likely to spark more innovation.9
Sure, I am aware that it is a challenge of biblical proportions, but your help may just be the flapping wing of a butterfly that we need for change.
“The great challenge of the twenty-first century is to raise people everywhere to a decent standard of living while preserving as much of the rest of life as possible.”
Edward O. Wilson (2006, p.17)
1. From BBC's Life Story (2014) narrated by Sir David Attenborough. To back up my choice for the octopus, I recommend watching the video narrated by ZeFrank.
2. See Rockström et al. (2009, Nature) and Kolbert (2014, p. 29).
3. I have taken the estimate for the background extinction rate from Rockström et al. (2009). The background extinction rate is estimated using fossil data, limiting the number of species that can be included in these estimations. Uncertainty about the total of number species complicates determining the background extinction rate as well. Using the 0.1 to 1 estimate gives an extinction rate of fifty to five hundred times the background extinction rate for amphibians over the last 30 years.
4. Quoted from the IUCN website, see Reilly et al. (2008), Goodrich et al. (2015), Singleton, Wich, and Griffiths (2008), and Ancrenaz et al. (2008), respectively. I was least precise about the tiger population, the estimate referred to the most populous subspecies, the Bengal tiger. Of the remaining five subspecies there are less than 1.500 mature individuals combined, and three subspecies have already gone extinct, see Arkive.
5. IUCN (2012, p.18), along with three other criteria based on population reductions, their geographic range and distribution. For the endangered category the probability of extinction criterion reads 20% within 20 years or five generations.
6. Quoted from Wilson (2006, p. 16) and see Douglas (2001, The Guardian).
7. See Bradley Cardinale et al. (2012, p.60-61, Nature) for the quote and references therein for evidence that biodiversity enhances the efficiency and the stability of ecosystems.
8. Rockström et al. (2009, p.474).
9. You may not feel as excited about protecting poisonous spiders, snakes or jellyfish, yet their venom may give improvements in medicine, for example in pain relief. Another already successful example comes from Stellar Biotechnologies Inc., which cultivates and protects a sea snail that produces a vaccine carrier protein used in immunotherapy. Other examples of innovations come from biomimicry – the imitation of nature’s solutions to human problems – e.g., termite hills inspired ventilation systems.