Unique and Alone On the EDGE of Existence

This is a guest post by Simon C. Moore, a Biology graduate and science writer who is interested in conservation and the human animal. For more of his writing check out his blog www.simonthescientist.wordpress.com and follow him on twitter @Simon_C_Moore.

Conservation is notoriously under-funded worldwide, despite our reliance on biodiversity to survive. It is estimated that over $76 billion is needed per year to successfully conserve the wildlife we are rapidly driving to extinction, but the actual spending figures are mere fractions of this amount. This lack is shocking when compared with money spent on the armed forces ($1.6 trillion per year), or video games ($101 billion per year). Consequently, tough decisions must be made over where to invest the little money that is available so as to best protect the many, many species on the brink of existence.

A new classification is being used among conservationists for particularly high priority species, as indicated by their evolutionary uniqueness and their vulnerability to extinction; EDGE species. The term ‘EDGE' stands for ‘Evolutionarily Distinct and Globally Endangered' and allows values to be given to threatened species so that we can determine those that are in most need of our help.

A number of criteria are assessed when prioritising species to be conserved and two of the most important are the amount of evolutionary history they alone represent, and their risk of extinction. All life on this planet is the result of approximately 3.6 billion years of evolution, however the species living today are not equally related to one another; time since last common ancestry varies widely. We can draw evolutionary trees based on genetic analyses which show us those species that have the fewest living relatives, and therefore represent a larger amount of unique evolutionary history, as this diagram illustrates.

These evolutionarily distinct species are important as they are disproportionately representative of biodiversity on our planet. Beyond its intrinsic value, biodiversity is crucial to maintaining ecosystem services such as food, water/air purification, pollination, medicinal resources, carbon sequestration and climate regulation. And most importantly it gives ecosystems greater resilience, meaning they are better able to cope with extreme environmental change and loss of species because they have a wide range of species that provide compensatory effects. Our planet is already fluctuating in terms of temperature, rainfall and extreme weather events and the more species we lose the more drastic the situation will become.

The International Union for the Conservation of Nature (IUCN) produces a ‘Red List of Threatened Species', which gives the conservation status of more than 70,000 species, and this is incorporated into a species' EDGE score. This status is based on data collected specifically for a given species, providing an indication of the degree to which they are threatened and the immediacy of the threat. This factor is hugely important for conservationists because it allows them to direct their precious attention and resources to saving those at greatest risk of extinction.

However, it must also be considered whether or not it is actually realistic for a species to be saved; a similar evaluation to that made by the emergency services, known as Triage. This technique assesses which species are headed to extinction and are likely beyond saving, which are at risk of extinction but have reasonable chance of survival, and which are probably going to survive without much assistance. It allows the most effective allocation of conservation resources to those species in great need but also with the potential to respond positively and survive in the long-term.

The EDGE of Existence program is run by the Zoological Society of London and seeks to redress the balance of conservation of EDGE species. They operate in over 20 countries, helping the careers of aspiring conservationists in their home countries, whilst raising awareness of the need to protect neglected species. They currently have lists of the top 100 most vulnerable/evolutionarily unique mammals, amphibians and birds, with plans to add sharks in the near future. Each species has its own detailed page providing up to date scientific knowledge that can be used by field workers and educators alike. Many species' extinction risks have not been assessed and are classified as ‘Data Deficient' on the IUCN Red List. Consequently, their EDGE score cannot be calculated and their conservation urgency remains somewhat unknown. Collecting this data is one of the primary goals of the program.

The Weird and Wonderful. The EDGE of Existence program currently has 12 different conservation projects underway. Clockwise from top left: Pygmy Hippo, Red Slender Loris, Pygmy Sloth and Chinese Giant Salamander.

Species based management strategies are important tools as they can effectively assess and counter the most pressing threat that a particular species faces. However, habitat level management strategies are also key to preserving biodiversity on this planet, as ecosystems are much more important than single species, no matter how evolutionarily distinct they are. Conservation relies heavily on public donations due to its poor funding situation, creating a need to market it to people; hence the attention lavished on charismatic species like pandas, tigers and elephants. The silver lining is that promoting conservation of one species has positive ‘umbrella effects' on the many other species that share their ecosystem, as protecting habitat for a species is integral to a successful strategy. An approach that focuses on protecting the complex ecosystems in which EDGE species live is most likely to prove successful, since these are often hotspots of biodiversity.

Further Reading