הופיע גם בגליליאו, מאי 2013
Species are disappearing before we even know what exactly they are.
If you’re a regular reader of Earth Island Journal or other environmental news sites, you probably know that plant and animals species around the globe are going extinct at the fastest rate in human history. According to the International Union for the Conservation of Nature, we are losing species at up to a thousand times the natural rate. Many experts now agree that Earth is heading for, or already experiencing, a mass extinction – the sixth in nearly half a billion years. The last mass extinction occurred about 65 million years ago when the dinosaurs, among the 76 percent of life forms at the time, were wiped out. Now, scientists believe, between 0.01 to 5 percent of the world’s species are lost every decade.
The reasons are many: encroaching urban development, pollution, hunting and illegal trade, expanding invasive species, climate change, and in many cases a perfect storm of few of the above. To help bring attention to the extinction crisis, in 2002 the United Nations declared May 22 “The International Day for Biodiversity.” The idea is to raise public awareness about how maintaining the planet’s biodiversity – the mosaic of creatures that makes up ecosystems – is essential.
Hopefully awareness will be raised, because there’s another associated problem confounding biologists: It appears many species could be gone before they were even known to science.
One of the less known aspects of the biodiversity crisis is the lack of scientific knowledge needed to even understand the extent of the problem. So far, researchers have documented about 1.5 million species. Every year nearly 18,000 more are added to the scientific corpus. But there’s still a long way to go, even in evaluating the knowledge gap itself. Estimates of the overall number of species on Earth range between two million and 100 million.
In short: We don’t know exactly how many species we share the planet with, so it’s difficult to know exactly how many we are losing.
The systematic classification of all species is done within the scientific field of taxonomy. Identifying and cataloguing species is key for a host of research and professional fields from medicine, to agriculture, to conservation. Taxonomists identify plants and animals, ascribe them to the appropriate hierarchic group (species, genus, family and so on), name them, and determine the evolutionary connections between them. In other words, taxonomy is the curation of the scientific knowledge of the natural world.
On its face, this might sound like boring clerical work. The academic field’s dull image might be contributing to what some refer to as a taxonomy crisis: waning human and financial resources mean that taxonomists themselves are now a rare species. There aren’t enough trained taxonomists to catalogue all of the planet’s species.
It turns out that a myriad of species are tucked away in the collections of universities and museums waiting to be described. A paper published in November 2012 showed that, on average, it takes 21 years from the first discovery, when a specimen is collected in the wild, until it is described as a new species in the scientific literature. At this rate, many species could go extinct during their “shelf life”, as the authors called this period of time. For some – like the Small Samoan flying fox (Pteropus allenorum) and the Burnt-tail Barb (Balantiocheilos ambusticauda) – it is possibly too late already.
Scientists and environmentalists are concerned that the so-called taxonomic impediment is making it difficult to address the extinction wave. Too often, says professor Tamar Dayan of the Tel Aviv University’s Department of Zoology, conservation measures are taken with insufficient knowledge. “We know a lot, but we don’t know enough,” she says. “We probably have very little time to learn how we can preserve the biological systems, how we manage them, and exploit them in a sustainable manner. The need to expand our ecological knowledge is acute.”
Thomas Brooks, head of IUCN’s Science and Knowledge Unit, stresses the urgency of tackling the biodiversity crisis. “In no discipline do we ever have perfect data, perfect knowledge,” he says. “And so, you always have to operate with the best knowledge, the best science that you have.”
Tracking and documenting the still-unknown species is an immense undertaking that requires extensive resources. But it isn’t impossible. Two years ago, Brazilian researchers calculated that completing the description of all animal species (that is, excluding plants and other organisms) would require an investment of $263 billion. According to researchers, the real hurdle is the limited number of professionally trained taxonomists. At this current rate of discovery and cataloguing, it would take approximately 360 years to complete the task.
There are others, however, who see the glass as half full. Increasing public awareness, improved technological capacities, and even the rise in the number of discoveries should all be reasons for optimism, a paper published in January contended. The number of people naming species is today three times as it has ever been,. “We’re in the golden age of taxonomy,” said co-author Mark Costello of the University of Auckland in New Zealand in an interview to the BBC.
In the paper, the researchers argued that not only is the number of people involved in taxonomy on the rise, but the total number of the world’s species is significantly smaller than common estimates, and the rate of extinction – while still worrying – is not as high as some have thought. As a result, the researchers believe, if current trends continue, science could complete mapping the entire natural world by the end of the century.
Several factors contribute to the taxonomic effort. One of them is the Internet. Exchange of information and access to data are easier and more effective than ever, thanks to a range of databases from around the world that are now available online. For example, the forums of BirdLife International allow academics and amateurs alike to contribute, through open deliberation, to assessments of the threat on different bird species. The data and its interpretations are later used by experts in formulating these species’ records on the IUCN Red List.
Another factor is the role of amateurs in discovering new species. According to a paper from May 2012, on average more than two new species were described every day in the past 60 years in Europe alone. The paper had no less than 51 authors from across the continent, but it showed that more than 60 percent of the new species were actually described by amateurs.
“I think amateurs’ role in conservation in general goes several centuries back in time, and indeed in taxonomy,” the IUCN’s Brooks says. “But over the last decade the emergence of the Internet has allowed a massive expansion of the ways in which amateurs can be connected to biodiversity conservation and to different approaches to citizen science.”
Professor Dayan is also optimistic, but she stresses that the extent of our knowledge of the natural world remains a contentious issue among academics. “The very fact that the literature deals with the state of a research field and how it affects science already suggests we have a serious problem,” she says.