Red colobus

• Our research, published today in the journal Global Change Biology, attempts to pin down why certain tetrapod species are rediscovered but others not.
• It also reveals that the number of lost tetrapod species is increasing decade-on-decade.
• This means that despite many searches, we are losing tetrapod species at a faster rate than we are rediscovering them.

Rediscoveries lead to conservation action

• Thus, rediscoveries are important: they provide evidence of the continued existence of highly threatened species, prompting funding for conservation action.
• The results or our study may help to prioritise searches for lost species.
• In the image below, we mapped their global distribution, identifying regions with many lost and few rediscovered species.

What factors influence rediscovery?

• Are there specific factors that influence rediscovery?
• We then proposed three broad hypotheses about factors that might influence rediscovery: characteristics of (i) tetrapod species, and (ii) the environment influence rediscovery, and (iii) human activities influence rediscovery.
• For example, body mass (a species characteristic) may positively influence rediscovery, as larger lost species should be easier to find.
• Based on these hypotheses, we collected data on a series of variables associated with each lost and rediscovered species (for example, their body mass), which we then analysed for their influence on rediscovery.

Hard to find + neglected = rediscovered

• In fact, since the completion of our study, De Winton’s Golden Mole (Cryptochloris wintoni) has been rediscovered in South Africa.
• Our results also suggest some species are neglected by conservation scientists, particularly those that are not considered to be charismatic, such as reptiles, small species and rodents.
• Voeltzkow’s chameleon (Furcifer voeltzkowi), a small reptile species, was rediscovered in Madagascar in 2018.

Lost or extinct?

• For example, remaining lost mammal species are, on average, three times larger than rediscovered mammal species.
• Furthermore, one third of remaining lost mammal species are endemic to islands, where tetrapod species are particularly vulnerable to extinction.
• Perhaps the limited resources available for biodiversity conservation would be better used to search for lost species likely to still exist.

Thomas Evans received funding from The Alexander von Humboldt Foundation.