Sunday, 22 September 2013

Going, going, gone: how do you decide which endangered species are worth saving?

My elder daughter recently adopted a Sumatran tiger. Not literally of course, but an Auckland Zoo package bought as a birthday present, with the tiger chosen above the seven other species on offer because - at least according to my daughter's claim - it was the most endangered one. In fact, the estimate for the number of Sumatran tigers left in the wild varies between four hundred and seven hundred individuals, so the lack of accuracy is only countered by the fact that both extremes are so low. With countless other species similarly close to the edge, if not worse off, a key question has arisen in recent years: are some species more worthy of conserving than others?

Presumably the choice on offer in the zoo's Adopt an Animal programme is intended to increase awareness of the plight of these particular animals. But can there be many people at least in the developed world who are not aware of some of the ever-increasing roster of endangered species? Indeed, there are now widespread claims that we may be living through a mass extinction event, the sixth known. Interestingly, it's only been in the last few years that some sort of quantitative definition of a mass extinction has gained popularity over the earlier, somewhat vague ‘one hundred to a thousand times the background rate' designation, with a rapid (at least on a geological timescale) 75% loss of species deemed the minimum number. However, this figure appears somewhat arbitrary, yet is quoted in various general readership articles as the number of species currently headed for extinction! Evolutionary biologist Richard Dawkins has much to say on the subject of fundamentally meaningless statistics: for example, how is 74% so much less worthy of the term ‘mass extinction' than a mere one per cent more? Granted, there may just be too many unknowns for a consensus in expert opinion, but deciding on a one per cent cut-off line for such an event is surely creating a label for its own sake, useful for lazy journalists but little else.

The International Union for Conservation of Nature (IUCN) Red List makes for depressing reading, with around 7000 species listed between the three worst categories: critically endangered; extinct in the wild; and species that have recently become totally extinct. Even worse, it appears to be out of date, if the example of the Yangtze River dolphin is anything to go by. It appears on the first of these lists, as opposed to the third, where most experts agree it should now sit. The fact that no single organisation seems to have enough resources to compile definitive current data doesn't help. After all, if you cannot identify the species most in need, how do governments and agencies decide which ones to save (and, unfortunately, which to doom to near-future extinction)?

The environmental movement of the past half century has long capitalised on photogenic ‘poster' species such as whales, apes and the giant panda, which add a wow factor that has had the side-effect of concentrating much of the funding on them. This has regrettably deprived many less aesthetic species of publicity, and probably in the case of some species such as the Yangtze River dolphin, their existence.

There are strong arguments both for and against the continuation of this policy, although things have recently got slightly better as regards recognition for non-figurehead species. Late last year the BBC television series Dara O Briain's Science Club made a foray into this area with the question - covered at the programme's usual break-neck speed -  are pandas worth all the money spent on them? Palaeontologist Richard Fortey and zoologist Lucy Cooke presented arguments seemingly against the high level of resources accorded the giant panda. Indeed, the latter emphasised the decline of one third of amphibian species worldwide. The time has finally come to appreciate that non-cute species deserve much greater attention than hitherto gained. To this end, the decidedly unpleasing looks of the deep-sea blobfish have recently seen it voted World's Ugliest Animal in a concerted effort to improve awareness of all the species that are least likely to appear on any fundraising poster.

So considering how many species, including plants and fungi, are currently endangered, is it worth spending millions of dollars each year to preserve, say, giant pandas? After all, aren't the latter just a wee bit useless? With a diet that is 99% bamboo and a seeming lack of reproductive drive, couldn't they be viewed as an over-specialised, evolutionary dead end, doomed regardless of loss of habitat and poaching? However, it isn't as simple as that. The popular description isn't completely accurate, with panda libido in captivity seemingly less than in the wild, although admittedly females are apparently only able to conceive for a few days each year. Even so, is it worthwhile to spend millions on captive breeding programmes (involving artificial insemination) for these cute creatures when the money could be split amongst many other species?

Auckland Zoo's adopt an animal scheme

Awww, cute...but is it worth it?

One of the key arguments in favour of figurehead species is that the publicity gained is then disseminated to other species in the same habitat, such as by keeping those environments as free of development as possible.  Preservation of entire ecosystems is a major element to the notion that for purely selfish reasons we should maintain as much biodiversity as possible. This is in order to preserve unique genomes that may one day prove useful in agriculture or as pharmaceuticals. After all, only about 5% of plant species have so far been studied for their medicinal properties, whilst the DNA of many species remains almost entirely unexamined. A good case can be seen with the Pacific yew, a conifer in severe decline that proved to be the source of an important chemotherapy drug. In a similar vein, loss of one species may cause the rise of another that is rather less neutral from a human viewpoint, whether it is an agricultural pest or a dangerous predator such as the aggressive Humboldt squid, which has largely superseded over-fished sharks around the Mexican Pacific coast.

So even without invoking a moral argument, there are plenty of good reasons why preserving as many types of organisms as possible may be important to our future.  Whether this can be achieved most efficiently via publicity-raising poster species is more difficult to ascertain. There are claims that we should support evolutionary-distinct species or those with a definitively viable breeding/cultivatable population, but this is hampered by the lack of detailed information mentioned above. For example, several population bottlenecks in the history of cheetahs have reduced their genetic diversity to such an extent that even a relatively comfortable population size - at least compared to some endangered species - is no guarantee of future salvation. In other words, the minimum viable population for a species is probably unique for each.

In addition, there aren't complete lists of members in each ecosystem for even relatively large creatures: it was only last month that the Olinguito, a Central American omnivorous mammal new to science, was formally described. With this lack of definitive information, it's little wonder there is a multitude of problems concerning even knowing where to begin conservation measures. Of course, spending funds on this sort of research, which has no immediate benefit to endangered species, would presumably take crucial funding away from vital preservation measures in the here and now. But since the research hasn't been done many factors remain little more than guestimates, thus creating a vicious circle as to which species require the most support.

This doesn't of course mean that dedicated ecologists are likely to be swayed from their labours of love by any amount of hard data. Whether the enormous efforts to save those species with miniscule populations is worthwhile in the long run remains to be seen. New Zealand's flightless parrot the kakapo, with less than one hundred breeding individuals left, is a prominent example. There are now so few that almost every bird has been named; but would it have been better to try saving multiple species with more likelihood of long-term survival? It's difficult to attempt objectivity when you are fighting for the survival of creatures that have been anthropomorphised even to the minimum level of naming them. Then again, it's often been the devotion of small groups of committed conservationists that pioneered the techniques now widespread, including the methods for publicising the plight of endangered species.

So it doesn't look like there are any easy answers in what has to be, if it is to succeed, a rapidly developing field. After all, it's only been a century since we stopped wiping out species for fun in the name of sport. Unlike the Higgs Bosun, some of the subjects involved in this area - the species themselves - aren't going to be hanging around for solutions at some indeterminate point in the future. As Gandhi put succinctly: "Earth provides enough to satisfy every man's needs, but not every man's greed." The problem is knowing where to begin on the mammoth task of fixing a planet-wide ecosystem. All I can say is good luck, because like it or not, we're all participants in this one!