May 17

A new study offers hope for the survival of species with critically low populations, such as the Siberian tiger and mountain gorilla, which in the past were deemed ‘too rare to save’.  

The findings of the UK-US research team, suggests that as long as conservation efforts target the key threats to an endangered species, even relatively small populations could be viable in the long term.

Photo of a captive Philippine eagle

Philippine eagle

Minimum Viable Population 

The study, published in the journal Trends in Ecology and Evolution, critically analysed the use of a key concept in conservation policies, the Minimum Viable Population (MVP). MVP is the estimated minimum size of a population that will have a 99% chance of avoiding extinction over the next 40 generations. 

Because, money and resources for conservation are limited, MVP is often used to decide whether or not a species should be the focus of conservation efforts. For species with very small populations, such as those numbering less than thousands of individuals, previous studies have suggested that it might be too late to act and that it is better to concentrate these limited conservation resources elsewhere. 

However, the authors of the latest study argue that there is no “magic number” for saving endangered species, and that population sizes required for long-term viability varies greatly and depend on the specific circumstances in which the population is found.

Photo of Siberian tigers greeting

Siberian tigers

Implications for endangered species 

The findings of the study have important implications for conserving some of the world’s most charismatic endangered species, which often exist in populations numbering in the hundreds, or even less. 

Examples include the mountain gorilla, which numbers 1,000 or less, the approximately 450 remaining Siberian tigers, the 180-500 remaining mature Philippine eagles, and the 70 wild Puerto Rican amazons

Dr. Greg Hayward, the U.S. Forest Service’s regional ecologist for Alaska said, “This is good news for biologists working to save species like the tiger. There’s a lot of work to do to arrest the effects of poaching, prey loss and habitat destruction. However, if that work is successful, the tiger might yet be able to recover, despite the relatively small size of most tiger populations.”

Photo of Mountain gorilla with young

Mountain gorilla

The authors argue that conservationists should not give up on saving an endangered species, even if its population is very small, and advise policy-makers to be cautious about setting guidelines for ‘safe’ population sizes. 

However, they also warn against potential complacency as no population size is likely to be safe from extinction when conservation activities fail to tackle the threats causing a species’ population to decline. 

Read more about this at ScienceDaily – ‘There’s No Magic Number for Saving Endangered Species’.

Alex Royan, ARKive Species Text Author

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