Issues Magazine

Nature’s Backbone Is at Risk


Conservation International

The most comprehensive assessment of the world’s vertebrates confirms an extinction crisis, with one-fifth of species threatened. However, the situation would be worse were it not for current global conservation efforts, according to a study published in the international journal Science.

The study used data for 25,000 species from The IUCN Red List of Threatened Species™ to investigate the status of the world’s vertebrates – mammals, birds, amphibians, reptiles and fishes – and how this status has changed over time. The results show that, on average, 50 species of mammal, bird and amphibian move closer to extinction each year due to the impacts of agricultural expansion, logging, over-exploitation and invasive alien species.

“The ‘backbone’ of biodiversity is being eroded,” said Professor Edward O. Wilson of Harvard University. “One small step up the Red List is one giant leap forward towards extinction. This is just a small window on the global losses currently taking place.”

South-East Asia has experienced the most dramatic recent losses, largely driven by the planting of export crops like oil palm, commercial hardwood timber operations, agricultural conversion to rice paddies, and unsustainable hunting. Parts of Central America, the tropical Andes of South America and even Australia have also all experienced marked losses, in particular due to the impact of the deadly chytrid fungus on amphibians.

Whilst the study confirms previous reports of continued biodiversity losses, it is the first to present clear evidence of the positive impact of conservation efforts around the globe. Results show that the status of biodiversity would have declined by at least an additional 20% if conservation action had not been taken.

“The critical point from our analysis is the role that conservation plays in slowing species losses. That means we can do something about this global problem by taking concerted action at local national and regional scales,” said Dr Andrew A. Rosenberg, Senior Vice President for Science and Knowledge at Conservation International and an author on the paper.

The study highlights 64 mammal, bird and amphibian species that have improved in status due to successful conservation action. This includes three species that were extinct in the wild and have since been reintroduced back to nature: the California condor (Gymnogyps californianus) and the black-footed ferret (Mustela nigripes) in the United States, and Przewalski’s horse (Equus ferus) in Mongolia.

Conservation efforts have been particularly successful at combatting invasive alien species on islands. The global population of Seychelles magpie-robin (Copsychus sechellarum) increased from fewer than 15 birds in 1965 to 180 in 2006 through the control of introduced predators like the brown rat (Rattus norvegicus) and captive-breeding and re-introduction programs. On Mauritius, six bird species have undergone recoveries in status, including the Mauritius kestrel (Falco punctatus), whose population has increased from just four birds in 1974 to nearly 1000.

In South America, protected areas and a combination of the Convention on International Trade in Endangered Species (CITES) and the Vicuña Convention helped spark the recovery of the Vicuña (Vicugna vicugna). Similarly, legislation enacted to ban commercial whaling has seen the humpback whale (Megaptera novaeangliae) move from “Vulnerable” to “Least Concern”. Unfortunately, very few amphibians have yet shown signs of recovery, but international efforts are escalating, including a program to reintroduce the Kihansi spray toad (Nectophrynoides asperginis) back into the wild in Tanzania.

The authors caution that their study represents only a minimum estimate of the true impact of conservation, highlighting that some 9% of threatened species have increasing populations. Their results show that conservation works if it is given resources and commitment. They also show that global responses will need to be substantially scaled up because the current level of conservation action is outweighed by the magnitude of threat. In this light, policy-makers have been calling for a very significant increase in resources.

The paper highlights that the percentage of species threatened among vertebrates ranges from 13% of birds to 41% of amphibians. Although the study focused on vertebrates, it also reports on the levels of threat among several other groups assessed for the IUCN Red List, including 14% of seagrasses, 32% of freshwater crayfish and 33% of reef-building corals.

The level of threat among cycads is extremely critical, with 63% threatened with extinction. Cycads, the most ancient group of seed plants alive today, are subject to extremely high levels of illegal harvesting and trade, and are in danger of going the same way as the dinosaurs.

Recently, a United Nations-sponsored study called The Economics of Ecosystems and Biodiversity calculated the cost of losing nature at $2–5 trillion per year, predominantly in poorer parts of the world. A recent study found that one-fifth of more than 5000 freshwater species in Africa are threatened, putting the livelihoods of millions of people dependent on these vital resources at risk.

Failure to meet the internationally agreed 2010 target to reduce biodiversity loss does not mean that conservation efforts have been in vain, as this study demonstrates. However, the erosion of biodiversity has reached such dangerous levels that we cannot afford to fail again.

Ambitious targets are needed for 2020, and to meet them will require urgent and concerted action on a greatly expanded scale. It is time for the world’s governments to rise effectively to this global challenge.