Biodiversity in decline, but conservation efforts making a difference

One-fifth of the world's mammals, birds, amphibians, reptiles and fish are threatened with extinction, according to a recent report. The study notes that there have been many conservation success stories, but far greater long-term resources are needed to improve the outlook for the world's threatened vertebrate species.

Biodiversity is of great cultural and economic importance for human society, but ecosystems can collapse if key individual species become extinct. Species found on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species are classified into eight categories, according to how close they are to becoming extinct. Species listed as 'Critically Endangered', 'Endangered' or 'Vulnerable' are collectively known as 'Threatened species'.

The greatest number of threatened bird, mammal and amphibian species occurs in tropical areas, with species in Southeast Asia particularly at risk. Amphibian populations are especially at risk in California, Central America, Australia and the tropical Andes in South America from the devastating fungal disease chytridiomycosis.

Human activities, such as agriculture, logging, over-exploitation of species and the introduction of invasive alien species, are primarily responsible for driving the global loss of biodiversity and pushing many species closer towards extinction. There is evidence, however, that conservation efforts can halt and even reverse biodiversity loss, provided there are sufficient resources and the collective will to protect habitats. Overall, biodiversity loss would have been at least one-fifth greater had it not been for conservation initiatives.

Birds and mammals have particularly benefited from conservation actions that reduce the threat posed by invasive alien species. However, conservation efforts to reduce the impact on habitats caused by agricultural expansion have been less successful. Robust agri-environment schemes and well-managed networks of protected areas are needed.

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