Population trends of 16 Critically Endangered species that would have gone extinct without conservation action, 1994 and 2004

Butchart et al. (2006)

An ultimate aim of conservation is to preserve biodiversity intact for future generations. A critical measure of conservation success, therefore, is whether conservation action has prevented any species from going extinct. Further, have any species had their extinction risk reduced and are now safer as a result of conservation?

Butchart et al. (2006) estimated that 16 species would have gone extinct during 1994–2004 were it not for conservation programmes that tackled their threats, reduced rates of population decline and/or increased population sizes. This estimate was based on assessments of candidate species’s population parameters, threats, and the nature and intensity of conservation actions implemented during the period. The mean minimum population size of the suite of species increased from 34 to 147 breeding individuals, while 63% of them had declining population trends in 1994, compared to 81% that were increasing by 2004.

A second study (Brooke et al. 2008) examined the rate that species have moved through the IUCN Red List categories towards extinction during the same decade, and argued that conservation action has substantially slowed this trajectory. While three Critically Endangered species had gone extinct by 2004, 49 species (28%) benefited from conservation action such that they declined less severely (24 species) or improved in status (25 species). An additional 47 species (27%) gained marginal benefits from conservation action. Hence, conservation action has for many species slowed, halted or even reversed the rates of decline driven by human-induced threats, and for a suite of 16 species saved them from, or staved off, extinction.