Rediscovering lost species and why it matters

News24

2 days ago

Rediscovering 'lost species' may sound like a pursuit of idealistic adventurers or a scientific box-ticking exercise but, in reality, it is a vital part of conserving biodiversity in South Africa and giving it a fighting chance, writes Dr Oliver Cowan.
How do you protect something if you do not know it is still alive? South Africa is home to a rich array of biodiversity with approximately 67 000 animal species and over 20 000 plant species - many of which occur nowhere else on earth.
These numbers are not static, however, and increase when new species are discovered and formally described, and decrease should a species be declared extinct.
The International Union for the Conservation of Nature (IUCN), through its Red List of Threatened Species, confirms a species' extinction only when there 'is no reasonable doubt that the last individual has died'. This is determined after exhaustive surveys across the species' known range have failed to find any individuals.
But what of those species in limbo? Known as 'lost species', they are defined by the re:Wild organisation as species that have not been recorded for 10 or more years.
Although South Africa is relatively well surveyed in comparison to many other parts of the world, species occurrence knowledge gaps still exist. This is generally attributable to either geographic reasons - remote and inaccessible areas are hard to get to - or due to a species' behavioural ecology such that standard survey efforts are ineffective at recording the species.
For example, soil-dwelling species can be challenging to find, the most energetic and swift species can be hard to capture or identify from a distance, and morphologically cryptic species can be difficult to separate from similar looking species.
But why is it important to fill these knowledge gaps?
Accurate and up-to-date knowledge of where a species occurs is a key component of assessing a species' risk of extinction which, in turn, informs decisions about land-use which enhances the protection of species of conservation concern.
For instance, effective spatial planning for protected area expansion and delineating critical or key biodiversity areas must account for the distribution of threatened species.
Similarly, legislation intended to protect species of conservation concern from further habitat loss relies heavily on this information.
For example, in South Africa the scoping phase of an environmental impact assessment must include a screening report that flags the presence of species of conservation concern within the proposed development footprint.
However, the data which informs the screening report's high sensitivity layer - requires records of species' occurrence from the past 20 years.
It is thus entirely plausible that knowledge gaps in the form of poorly sampled regions, and/or a lack of robust extinction risk assessments, result in species slipping through the cracks. They may lose important habitat simply because we did not know that they were there.
Conservationists know that targeted, species-specific surveys are essential to rediscover lost species. Unfortunately, the financial resources, time and effort needed to support these surveys are not insignificant.
Nevertheless, in recent years there has been an uptick in the rediscovery of lost species. These include the rediscovery of De Winton's golden mole (Cryptochloris wintoni) in 2021 after it was last recorded in 1937; Pennington's blue butterfly (Lepidochrysops penningtoni) – rediscovered in 2021, last recorded in 1968; the orange-tailed sandveld lizard (Nucras aurantiaca) – rediscovered in 2022, last recorded in 2005; Branch's rain frog (Breviceps branchii) – rediscovered in 2023, last recorded in 2008; and the Blyde Rondawel flat gecko (Afroedura rondavelica) – rediscovered in 2025 after 33 years.
READ | SEE | Five 'lost' species that have been recovered in SA
The orange-tailed sandveld lizard is a prime example of the importance of targeted surveys. This charismatic reptile had miraculously only been captured once, in 2005 near Lambert's Bay, and subsequently incidentally photographed on a camera trap in 2011. The habitat in which the species is known to occur has undergone substantial historical transformations, mostly due to agriculture, and in more recent years, a slew of mining developments have occurred along the West Coast.
Indeed, in 2022, a right to prospect for phosphate ore was granted that encompassed both known localities of the lizard. However, due to the paucity of information on this lost species, it was categorised as 'data deficient.' The animal's rediscovery, and the data gathered during the week-long survey, will see the species uplisted to 'endangered' and it will need to be accounted for during future development proposals.
Although the aforementioned species were rediscovered thanks to expert-led surveys and supported by funding awarded to conservation NGOs, the potential role of citizen scientists should not be underestimated. With just a smartphone, apps such as iNaturalist allow anyone to upload photos and locations of species they encounter to an online database where taxonomic experts or fellow citizen scientists can identify them.
In recent years, a hiker posted a picture of the cream-spotted mountain snake (Montaspis gilvomaculata) from the Drakensberg, 22 years after it was last recorded, and two records of the long-tailed forest shrew (Myosorex longicaudatus) were verified after three decades with no sightings.
Not all lost species end up being found.
Despite a number of targeted surveys to rediscover Eastwood's long-tailed seps (Tetradactylus eastwoodae), the species has not been recorded for over 90 years and is now officially extinct. This is a stark reminder of the pressures facing biodiversity in South Africa.
The continued degradation and loss of natural habitat, combined with a rapidly changing climate will undoubtedly see an upsurge in extinctions in the coming decades.
Nevertheless, directing the limited resources at our disposal to best conserve our country's biodiversity requires robust and up-to-date information on species, and the importance of rediscovering lost species should not be overlooked. Rediscovering these species is not just about scientific curiosity - it is about ensuring they remain part of our shared natural heritage and whether through structured surveys, bioblitzes, or a well-timed iNaturalist post, we all have a role to play.
Dr Oliver Cowan is a conservation scientist at Endangered Wildlife Trust.