Negative impact of conservation on non-target species

Conservation efforts to protect one species may have a negative impact on the population size of another species. For example, if both species compete for the same prey, and protecting the prey negatively affects the predator species, or if one prey species supports the common predator of another species.

Nº 15

1) United States, Channel Islands

2) Japan, Tokunoshima Island

3) Australia, Macquarie Island

some attempts made
past case
Region-1
Region-2
Region-3
Region-4
ongoing case
no attempts made

Negative impact of conservation on non-target species

Conservation efforts to protect one species may have a negative impact on the population size of another species. For example, if both species compete for the same prey, and protecting the prey negatively affects the predator species, or if one prey species supports the common predator of another species.

1) Six subspecies of the island fox have become extinct or critically endangered on the various islands of the Californian Channel Islands system due to the colonisation of the islands by golden eagles. Golden eagles, birds of prey with special legal status, were attracted to the islands following the human introduction of feral pigs, which put pressure on the native island foxes.

2) Free-roaming cats on Tokunoshima Island, which enjoy human-assisted feeding, are disrupting natural areas of high biodiversity.

3) After the introduction of rabbits, the feral cat population on Macquarie Island grew rapidly, leading to the extinction of an endemic parakeet. The two species had coexisted for decades before the rabbits arrived.

1) Courchamp, F., Woodroffe, R., & Roemer, G. (2003). Removing Protected Populations to Save Endangered Species. Science, 302(5650), 1532–1532. https://doi.org/10.1126/science.1089492

2) Maeda, T., Nakashita, R., Shionosaki, K. et al. (2019). Predation on endangered species by human-subsidized domestic cats on Tokunoshima Island. Sci Rep 9, 16200. https://doi.org/10.1038/s41598-019-52472-3

3) Taylor, R. H. (1979). How the Macquarie Island Parakeet Became Extinct. New Zealand Journal of Ecology, 2, 42–45. https://www.jstor.org/stable/24052640

Marshall, K.N., Stier, A.C., Samhouri, J.F., Kelly, R.P., Ward & E.J. (2015). Conservation Challenges of Predator Recovery . Policy Perspectives, 9(1), 70-78. https://doi.org/10.1111/conl.12187

Courchamp, F., Woodroffe, R., & Roemer, G. (2003). Removing protected populations to save endangered species. Science, 302(5650), 1532-1532. https://doi.org/10.1126/science.1089492

Holt, R. D., & Bonsall, M. B. (2017). Apparent competition. Annual Review of Ecology, Evolution, and Systematics, 48, 447-471. https://doi.org/10.1146/annurev-ecolsys-110316-022628