2022 May 22
The International Union for Conservation of Nature (IUCN) Red List is more than a list; it is a barometer on life. Just as a barometer forecasts the weather from atmospheric pressure, the IUCN Red List measures pressure on species, guiding scientists, conservationists and decision-makers to implement conservation actions to prevent species extinction. It is the most comprehensive collection of information on threatened species, their conservation status and their links to livelihoods. It is used to guide scientific research, inform policy and conservation planning and improve decision making, to protect the natural resources on which we all depend.
The IUCN works with a global network of specialists, who collect data, carry out assessments and monitor the status of entire groups of species. Each year, more assessments are added, continually improving the List’s ability to represent the world’s biodiversity.
How things stand today
The IUCN Red List Categories define the extinction risk of species, and are as follows:
- Extinct or Extinct in the Wild
- Critically Endangered, Endangered and Vulnerable: species threatened with global extinction.
- Near Threatened: species close to the threatened thresholds or that would be threatened without ongoing conservation measures.
- Least Concern: species evaluated with a lower risk of extinction.
- Data Deficient: no assessment because of insufficient data.
The IUCN Red List of Threatened Species, 2020
Species in the Vulnerable, Endangered and Critically Endangered categories are collectively described as ‘Threatened’. By 2020, there were 128, 918 species on the IUCN Red List, of whom 37, 400 have been threatened with extinction.
In Sri Lanka, 30 species of mammals, 14 species of birds, 13 species of reptiles, 75 species of amphibians, 121 species of fish and 298 species of plants are listed as Threatened (IUCN Red List version 2020-2).
Clinging to the edge
The recent List assessment of the amphibians of Sri Lanka has highlighted that 72 of them are threatened with extinction, with 20 critically endangered. Though a small Indian Ocean island, Sri Lanka is recognized as an amphibian hotspot, with 116 species, 90% of whom are found nowhere else on Earth. Sadly, Sri Lanka has also recorded the highest number of amphibian extinctions in the world, while rediscovering just three of the 21 amphibian species previously considered extinct, highlighting the need for more research and strategies for amphibian conservation.
Sri Lanka’s Bigfoot Shrub Frog (Pseudophilautus macropus) is now listed as Critically Endangered (CE). This species is endemic to Sri Lanka and occurs in sub-montane tropical moist forests and in cardamom plantations (provided there has been no agrochemical use). Although previously reported from several locations of the island, recent information indicates that they are now limited to a small area of the Knuckles Range of central Sri Lanka. The main threats are identified as habitat loss due to agriculture – cardamom cultivation, firewood collection, and agrochemical pollution of land and water, specifically the use of insecticides.
Two of Sri Lanka’s iconic mammals – the Red Slender Loris and the Purple-faced Langur – continue to be listed as ‘Endangered’, as well as a member of the family Soricidae – the Ceylon Pygmy Shrew.
The Red Slender Loris (Loris tardigradus) is listed as Endangered (EN) with a population size estimated to be fewer than 2, 500 mature individuals in the wild. It is endemic to the rainforests of Sri Lanka, and is typically found in the “south-western wet zone” of the island, up to the central highland. The species is listed on CITES Appendix II and is protected under the Fauna and Flora Protection Ordinance (FFPO). Habitat loss and fragmentation, due to agricultural expansion, urbanisation, uncontrolled exploitation of forest products (ex: firewood), illegal encroachment, alien species invasion and mismanagement by the relevant authorities, are listed as their main threats.
The Purple-faced Langur (Semnopithecus vetulus) is endemic to Sri Lanka and occurs throughout the island. They are highly arboreal, inhibiting forests along the western and southwestern coasts and extending eastwards beyond the lowland rainforests into intermediate and dry zone forests, and the cloud forests in the centre of the island. This species is listed as Endangered (EN) and thought to have undergone a decline of more than 50% in number over the last three generations (36 years, given a generation length of 12 years) due to habitat loss resulting from selective logging, expanding human settlements, agriculture, plantations, as well as ill-conceived capture and releases, which have increased human-primate conflicts. Out of the four (4) subspecies within this parent species, the Western Purple-face Langur (Semnopithecus vetulus ssp. Nestor) is listed as Critically Endangered (CE). This subspecies is found in Western Sri Lanka, north of the Kalu Ganga river up to 1,000 m where urban development around the capital Colombo has resulted in extensive deforestation. It is estimated that nearly 80% of this monkey’s range has been deforested and the remaining population survives mainly in home gardens and several small forest fragments. To promote the conservation of all four subspecies, Molur et al. recommended several actions such as habitat management, scientific research, population monitoring, viability analyses, implementation of extant conservation laws and public education.
The Ceylon Pygmy Shrew (Suncus fellowesgordoni), Podi Hik-miya in Sinhala, is a nocturnal and terrestrial shrew living in montane forests and wet patana grasslands including the Knuckles Forest Reserve. The species is protected under the FFPO. There is little information available on the population abundance of this species and they have been listed as Endangered (EN). This species is restricted to a small area, where the habitat is declining and other threats include fire and conversion of suitable habitat to plantations of cardamom and tea. The use of pesticides on tea plantations has increased and this may also affect the species.
The Ashy-headed Laughing thrush (Garrulax cinereifrons) is a bird endemic to Sri Lanka and is confined to the lowlands, particularly across primary and secondary rainforests and adjacent hills of the wet zone in the south-west of the island. Little is known of its population, and where it was previously thought to number a few thousand individuals, the population is now likely more abundant. The population is, however, suspected to be undergoing moderate declines. The main threat is the extensive clearance of forests, particularly in the wet zone, through logging, collection of wood for fuel, conversion to agriculture and tree plantations, gem mining, human settlement and fire.
Not just animals
The Sri Lanka legume (Crudia zeylanica), known as “Pandu Karanda” in Sinhala, is a large tree of the wet lowlands, including on stream banks which get periodically inundated. It was once thought to be extinct but the tree was rediscovered in 2019 and has became famous after being threatened by a road expansion project prompting an outcry from conservationists and the general public. Since then, specimens have been found in six (6) other locations allowing for the seeds to be germinated in a lab.
The plant species Trigonostemon diplopetalus is endemic to Sri Lanka and listed as Critically Endangered (CE), with a small extent of occurrence and area of occupancy, both below 10 km². The species’ current location is surrounded by degraded forests. Habitat loss is the result of the development of settlements and urban areas, roads and lowland logging activities. These threats may have caused the species to come close to extinction.
Rathatiya (Palaquium thwaitesii) is endemic to Sri Lanka and found in the south-western part in just four locations. The species has been established in the Sinharaja Forest Reserve, as a conservation strategy, where individuals receive a level of added protection.
Listed as Critically Engendered (CE), (Palaquium laevifolium), Wana-Mi in Sinhala, is a medium-sized tree growing in the understory of tropical wet lowland evergreen forests. This species is also endemic to Sri Lanka. Forest degradation by logging, expanding infrastructure and land conversions is their main threat. Research is needed to better understand this species’ conservation needs; however, specimens have been collected in the Sinharaja Forest Reserve where individuals may receive a level of extra protection.
Palaquium canaliculatum, Elakirihembiliya in Sinhala, is an endemic species which occurs in the southwestern part of the country. Listed as being Endangered (EN), the tree is said to have been found in or close to places such as Colombo, Weligama and Kalutara. If still present in these areas, fragmentation of habitat and expanding infrastructure are their main threats.
Only the first step
It is important to note that not being on the Red List does not mean that species are not threatened. It simply means that species have not been assessed as yet. Unlisted species may still be threatened, and even go extinct, without our knowledge! That is why it is important that countries invest in the required scientific research so that more species can be assessed each year. This is especially true of island nations like Sri Lanka, where biological endemism is very high – 16% of the fauna and 23% of flowering plants in Sri Lanka are endemic. The IUCN strongly recommends that the Red List must also be supported by National Red Lists, Local Surveys, and Conservation Priority Lists collated in consultation with Species Experts.
The IUCN Red List must be looked to as a wake-up call, highlighting the vulnerability of the natural world resulting from the terrible impacts of this Anthropocene era. It must also be said that the Red List is not all bad news either, there are occasional good-news stories too, demonstrating that by implementing adequate conservation measures, species CAN be saved from extinction and, along with them, our very lives too, and the livelihoods of many local communities.
“Listing the conservation status is only the first step towards conserving threatened species. This should be followed with 3 other important steps which are planning, implementation and monitoring. It appears that Sri Lanka has failed to address these issues; appreciably. This clearly indicates that even though the need to conserve threatened species has been recognised, the necessary steps to conserve them have not been taken.”
Prof. Devaka Weerakoon