Canberra, August 28 : A research team from Australia, France and the UK has used mathematic modelling to determine when conservationists should manage species.

According to a report by ABC News, the model indicates that when conservationists should switch their efforts from managing the environment, to actively searching for a vanished species or giving up altogether.

"The most cost-effective strategy is to assume a species still exists, even if it hasn''t been seen for some time," said the researchers.

"Conservationists should carry on managing the environment as if a seemingly vanished species is still around, rather than rushing to check whether it is extinct," they added.

The research, headed by Dr Iadine Chades from the University of Queensland, appears online in the journal Proceedings of the National Academy of Science.

According to research group leader, Professor Hugh Possingham, animals or plants that have not been seen for some time are known to scientists as "cryptic species".

"A lot of threatened species are cryptic. The question is how do you know how to best protect them?" he said.

The researchers found that assuming the species is still around, even though it has not been seen for some time, is the most cost-effective strategy.

"It''s really about what do you do for a cryptic species if you haven''t seen it for a long time," said Possingham.

"What was counterintuitive was the length of time you should keep for managing the environment. We showed that often you should manage for a lot longer without seeing them," he added.

Several factors influenced just how long conservationists should wait before starting to search for a species, according to Possingham .

Those factors include the value of the species, its detectability and its probability of extinction.

The bottom line, however, was that money should be spent first in managing the environment to give a threatened species the best chance of survival, rather than engaging in efforts to survey for its presence.

"Thus, the optimal strategy is to invest in active protection," said Possingham.

In their paper, the researchers focused on a population of the Sumatran tiger that had apparently vanished from certain areas, but may or may not have become extinct.

Their models suggest that if the Sumatran tiger is detected in the reserve, the optimal strategy is to manage it for 12 years from that time.

However, if the species is not observed during that 12-year period, all resources should be switched from managing the tiger back to surveying.

"If the species remains unobserved for a further 3 years of dedicated surveying, the optimal strategy is to stop investing resources in conserving this species," said the researchers. (ANI)