EDGE Community

Project information

[Project name/title]
Red Slender Loris EDGE Conservation Programme

[Project description/overview]
The red slender loris (Loris tardigradus) is a nocturnal primate and has been the focus of considerable research interest over the past decade. However, despite this interest only limited data are available for the accurate evaluation of their conservation status or applied management needs. A group of committed experts and interested parties gathered in February 2009 to determine priority areas to which conservation research funding should be applied. Within the scope of a single year of funding a focus has been placed on provision of required skills training, resolution of key research questions achievable within such a timeframe (species distribution, range and taxonomy), the development of baseline data and a data management and analysis systems to offer a robust measure of change in habitat patch occupancy over time. Provision of training materials and opportunities to develop technical capacity in potential partner organizations such as the Department of Wildlife Conservation (DWC) and the Forestry Department (FD) as well as within educational establishments will also be a significant component of the project.

Finally, a conservation action plan will be generated in concert with findings of field research, and interactions with management agencies that will hopefully act as a guiding foundation document for national commitment to applied conservation management of loris habitat and populations, if deemed necessary by the Sri Lankan Loris Conservation Group following outcomes of this study.

Sri Lanka, an island off the southern-most point of India, is known as a global biodiversity hotspot for its high number of species in a relatively limited area. The island's amphibian diversity illustrates this point: despite covering only 0.013 percent of the world's land surface, Sri Lanka is home to more than 2 percent of the world's known amphibian species. The island is also home to nearly a thousand species of endemic plants and overall, about 27 percent of the Sri Lankan flora and 22 percent of its vertebrate fauna are endemic. The islands' isolation from the mainland, two bi-directional monsoons and three disparate mountainous regions have created a variation in climate and therefore ecology which is normally found at the continent scale. Sri Lanka (together with the Western Ghats) is amongst the eight biodiversity hyper-hot spots in the world. Sri Lanka has the second highest human population growth in the Asia region putting its resources at extraordinary risk.

Project type:

Relevant EDGE species:
Red Slender Loris (Loris tardigradus)

Project members:
Saman Gamage
Craig Turner

Relevant species
67. Red Slender Loris (Loris tardigradus) EN

The slender loris is characterised by its enormous eyes and extremely thin limbs.

[Relevance description]

The project ultimately aims to better understand the past and current threats facing the loris, its current status (in terms of population and distribution) and its conservation needs.

The principal threat facing the slender loris is habitat change, resulting from nearly two centuries of over exploitation for coffee, tea, rubber, and cinnamon. Combine with the facts that the species is endemic to central and south-western Sri Lanka, and is typically found in the southern “wet zone” of the island, up to the central “intermediate zone”, and the picture is bleak.

The lorises of Sri Lanka are valuable and characteristic members of the nation’s rich biodiversity. A number of ecological studies have been conducted on several of the described loris taxa largely during the last decade and many of these studies have suggested the need for further conservation research and focused conservation management of these species by the national resource management agencies and/or capable NGOs.

Due to these publications and the classification of Slender loris within the IUCN red list it is now desirable to advance the knowledge required and the linkages between scientific research, national policy and management agencies to ensure their persistence within Sri Lankan ecosystems.
Project summary
The Red Slender Loris EDGE conservation programme run by ZSL in collaboration with the University of Colombo and Open University of Sri Lanka, has been underway since 2008. It is assessing the range, distribution and status of loris species across south-western Sri Lanka in order to inform the development of appropriate conservation strategies.

A key part of this has been undertaking an assessment of loris ‘occupancy’ in over 120 different forest patches, with nearly 1000 surveys completed. Led by the project’s Sri Lankan field team, this has provided the first spatial data on loris at this scale in Sri Lanka allowing questions regarding habitat use, forest preferences, and distribution to finally be answered. This information is fundamental in informing a conservation action plan which is currently being drafted. Add to the mix, on going taxonomic work, and conservation awareness and educations programmes being implemented by the team across south-western Sri Lanka and the conservation picture begins to look a lot brighter.

The project will not only result in various technical outputs from peer-review papers to GIS regarding the distribution, habitat needs and threats to the loris, it will also help us resolve the taxonomy – how many species (or sub-species are we dealing with?). All of which will be used to inform a Conservation Action Plan which will be drawn up later in 2010.

The primary objectives for addressing the main conservation concerns are:


Reliable data on occurrence and extent of the Loris tardigradus complex appears very limited despite a decade of research engagement. Conservation management demands more reliable and systematic survey to verify the distribution boundaries of the Loris tardigradus complex for the identification of spatial conservation units. In addition, robust trend data capable of demonstrating changes in species circumstances is an essential component to any competent species conservation management plan. Loris habitat use and preference is also still ill-defined for certain critical ecotypes such as home gardens and montane forest. A well designed monitoring programme which focuses primarily on repeat surveys recording presence or absence should be able to deliver robust baseline data within one year. Habitat patches will be monitoring in primary, secondary and home garden ecotypes. This is a precursor to establishment of a monitoring programme design and analysis procedure and robust baseline data. Monitoring sites must conform to specific criteria and can be established whilst collecting data for the distribution study.
1. Current distribution of slender loris in the wet and intermediate zone
2. Establish sites for long-term monitoring of Loris in protected and non-protected sites including montane forest, primary rainforest, secondary rainforest and home garden ecotypes
3. Provide training in occupancy monitoring methodologies and analysis techniques to core project personnel and local biometricians
4. Develop estimates of detection probability in different habitat types
5. construct a data set and analysis outputs that are capable of addressing the question of whether proportional occupancy of habitat patches is influenced by ecotype and/or environmental variables


Species and subspecies boundaries remain confused within the Loris tardigradus complex and Sri Lankan researchers suggest that cryptic taxa may be included within the current four described subspecies due to regionally specific polymorphisms observed. It has been suggested that L.t.nycticeboides may be distinct species in its own right and if this is the case then this species is likely to be considered critically endangered, and requiring of further conservation attention.
1. Investigate systematics of L. tardigradus complex and prepare capacity to continue work to include other Sri Lankan loris taxa
2. Should L.t.nycticeboides prove to be a good species or achieve a new taxonomic status then publication of findings in primate taxonomy literature
3. Develop a diagnostic key for species and subspecies in Sri Lanka

Awareness programmes will be conducted where the opportunity arises during the field programme to advocate the conservation of slender loris and habitat. This will be conducted through community workshops, school education programmes, and close involvement with local schools and science/environmental education teachers. A focused effort will also be made to achieve greater understanding of loris biology, ecology and conservation need amongst DWC and DF planning and field staff.

All wildlife should fall under a management plan of some form. It is increasingly becoming the case, especially amongst habitat sensitive species and vertebrates, that a species specific management plan is necessary for the security of those species and to enable governments to fulfil and act upon the . Through the expert working group formed to review this proposed programme, existing literature and the findings of research as described here, we will deliver a conservation action plan (CAP) for slender loris by the end of this programme that may initiate the formation of a species management and/or recovery programme for some or all of the taxa involved. Should specific resource management methods be necessary to safeguard loris in Sri Lanka or to facilitate their recovery if taxa are confirmed as in imminent peril of extinction then the CAP and following recovery plan must be governmentally endorsed (through appropriate resource management agencies) and include a focus on mechanisms to achieve sustainable environmental management and investment.

Notable successes to date, include:

The establishment of a national association of experts and authorities, with the primary objective of determining priority action areas for research, conservation and education.

Rediscovery of the virtually unknown Horton Plains slender loris (Loris tardigradus nycticeboides). Originally documented in 1937, there have only been four known encounters in the past 72 years. The rediscovery and capture by the team (working under the ZSL EDGE programme) has resulted in the first detailed physical examination of this sub-species.

The Horton Plains slender loris is evidently extremely rare and was only found after more than 200 hrs of nocturnal transect surveys in the known habitat. The red slender loris is a focal EDGE species, and the rarity of L. t. nycticeboides resulted in it being listed as one of the world’s 25 most endangered primates.

Project members
Saman Gamage : Principal Researcher

Saman is president of both LORRIS and PCSSL in Sri Lanka

[Member role description]
Within this project:
Saman leads the field research and co-ordinates multiple field teams.
Dr Craig Turner : Project Manager

Craig recently co-led the Negros Interior Biodiversity Expedition in the Philippines

[Member role description]
Within this project:
Co-ordinate the project with our Sri Lankan partners and provide technical support for the ongoing field work and production of project outputs.
Project partners
University of Colombo
Open University of Sri Lanka
[Image caption]
Red Slender Loris
[Image caption]
The Loris Field Team
Associated Blog Posts
24th Mar 14
The Montane Evergreen Forests (MEF) of Sri Lanka is beginning to expand. This is great news for the Horton Plains slender loris (HPSL), a subspecies which is...  Read

26th Sep 12
The Montane Evergreen Forests (MEF) of Sri Lanka will soon be expanding. This is great news for the Horton Plains slender loris (HPSL), a subspecies which i...  Read

19th Sep 12
You may not be aware that we are currently in the midst of loris awareness week (http://www.nocturama.org/its-loris-awareness-week/), an event that is being ...  Read

16th Sep 11
Taking a trip to a primary school to join up with a Tuk Tuk rally to do some tree planting was not part of our original plan to launch our forest corrido...  Read

13th Jun 11
Note: Thank you to everyone who supported this campaign and helped us reach our target! if you would like to keep supporting EDGE project consider a monthly ...  Read

19th Jul 10
A massive occupancy monitoring programme has been initiated over the past 18 months to assess the persistence of lorises in over 100 of the remaining fragmen...  Read

1st May 08
One of our EDGE Fellows, Vijitha Perera, started fieldwork in March on the red slender loris (Loris tardigradus) in the Knuckles Range, Sri Lanka. Vijitha se...  Read

[Image caption]
Looking for loris
[Image caption]
[Image caption]
Expert working group
[Image caption]
Taking morphometric data
[Image caption]
[Image caption]