“Hola Gente! I am the virtuous Tennent’s leaf-nosed lizard belonging to the family Agamidae, also known as dragon lizards. Being diurnals, our lineage has the perfect vision and is significantly renowned for our crests and embellishments that we mostly use to shoot the breeze, set up and uphold our dominions, and for courtships. Scientists have named us Ceratophora tennentii due to our characteristically flattened, leaf-like elongated ornamentation at the tip of our snouts. We, leaf-nosed lizards exist in multifarious colours from reddish-brown to olive green and my dazzling lady lizards are paler than us with much shorter projections. Worse luck we aren’t very agile, but we possess a remarkable ability to camouflage ourselves from the monstrous feathered creatures and serpents. These enthusiastic ladies and gentlemen here, reading this may or probably may not know that I am endemic to Sri Lanka and was enthroned as one of the first Sri Lankan reptilian species to be assessed for the International Union for Conservation of Nature (IUCN) Red List (IUCN 1996). From the onset, they have nationally evaluated me as a ‘critically endangered’ species based on the very limited extent of my occurrence, the tropical montane forest Knuckles Hill ranges of Sri Lanka’s wet zone.”
Sri Lanka, being a splendid tropical island, is considered the world’s prominent herpetological hotspot that provides habitats for 233 reptile species where 62.6% out of them are endemic. This much diversity is an exceptional gift for an island of this size, yet woefully it’s vastly underestimated.
The History runs for centuries back…
Tennent’s leaf-nosed lizards are mostly restricted to the Knuckles Mountain range which is a tropical montane cloud forest of Sri Lanka’s wet zone between 700 and 1300 m above sea level. In 1840, numerous lands of this pearl island were named as ‘crown lands’ under the British administration announcing the evil chapter. Deforestation was expedited and massive areas were cleared for tea and coffee plantations. Later in this era, the slash-and-burn (chena) cultivations also raised in demand among countrymen which in turn caused disastrous effects on the forest cover. The widely occupied montane forest areas started to shrink up to ~3000 ha as isolated patches and Knuckles hills as live consequences of afforestation with non-native timbers like Eucalyptus, Cupressus, Pinus etc in the 1890s and onsetting commercial-scale underplanting of the forest with cardamon in 1960s. For the last couple of years, logging companies and nearby villagers have been carrying on with illegal logging and timber removal from the heritage sites.
Anthropogenic activities are the roots of the threats…
With the accelerated population growth, the demand for agricultural lands is ever-increasing. Humans tend to alter natural habitats by degradation and fragmentation to fulfil their selfish needs and wants. This is more prominent especially in developing countries where land management practices are even relatively poor.
The small range of area that was occupied by montane forests now has been replaced by monocultures including tea, pine and cardamom. These cardamon plantations require the clearance of the understory layer in forests which substantially alter the vegetation structure of the Knuckles area raising a red flag to sympatric agamids. Clean weeding not only provokes soil erosion but also hinders the natural regeneration of the forest and turn down the ground leaf-litter levels where these lizards bury their eggs. Another complicacy is the utilization of agrochemicals reduce the prey populations like caterpillars, cockroaches, bees, moths, large ants that leaf-nosed lizard depends upon. These sedentary non – agile lizards are not inclined to actively hunt, instead, they select habitat pockets with plenty of food supply. Pines in Knuckle’s ecology produce a sticky flammable litter that can possibly cause out-of-control forest fires and even human activities and improper chena cultivations can lead to catastrophic fires destroying the habitat.
Perpetual harvesting of large trees opens the higher canopy increasing the forest’s temperature and reducing the humidity. Adapting to these conditional changes in the surrounding environment is a harsh challenge to overcome. Being creatures that rely on body colourations for protection, openness unarguably raises the vulnerability to predators.
Although some farmers are masters in identifying and aware of C. tennentii, some still strongly believe that lizards are destructive. Rural regions in other countries consume these agamid species as food or kill them to use in traditional medicines.
Plans have been implemented targeting the conservation of these species…
The Assess-Plan-Act cycle was introduced by ICUN’s Species Survival Commission where effective action plans of conservation are carried out for every species individually. Coordination of an international press release to raise global awareness, educating forest rangers, foresters, and community on the threatened species, initiating a research plan linked with the parliament and universities to study the impacts, are some of the next steps taken to the site-based conservation of the Knuckles Hill Forest.
Forest areas 1,067m above the sea level were identified and protected in 2000 abandoning the cardamom cultivations. This didn’t come out as a successful pre-measure due to the taking over of cardamom regions by invasive weeds such as mistflower (Eupatorium riparium) and lantana (Lantana camara). After IUCN listed the leaf-nosed lizard on the endangered list in 2006, it was shielded making its trade illegal.
Yet, we can do more…
First and foremost, the most essential thing is to understand the reactions of the species to environmental modifications and their distributions through space and time to effectively conserve in modified landscapes. The deficiency in required resources interrupts conservation management. However, this goal can be approached in a different path by improvising the understanding about the possible threats so that wildlife officers can prioritize efficiently based on those.
Studies have shown that despite the clearings and removal of canopy trees, C. tennentii can retain higher densities in mixed cardamom forests instead of undisturbed forest patches. As vegetations promote greater niches and species richness, a higher abundance of food and the availability of their desired specific microhabitats such as grasslands promotes the dispersion. Cardamoms can be experimentally eliminated from the natural forests reducing their density and then spreading of weedy herbaceous species such as Lantana camara can be done.
In-situ biodiversity conservation steps were also suggested by research. Species diversity can be increased in numbers by establishing habitat corridors across other island forests and montane forests. This will help to overcome the dispersal barriers faced by species in the Knuckles range due to Pine plantations. By proper planning and with the involvement of positive human activities these areas could be restored. Pine plantations can be replaced with important medicinal plants, food crops and timber species that adds an economically valuable perspective to rural communities. This in turn will create favourable corridors for the dispersal of fauna and especially for the C.tennentii as they are largely terrestrial.
Apart from all the tactics used in the conservation of these prideful species the most effective and practical scenario is the involvement of humans in managing ecosystems. Utilizing ecosystems while safeguarding the massive biodiversity is the finest and easiest duty that we all can contribute to. More strategies can be developed based on the acquisition of detailed knowledge from explorations.
“My dear benign earthlings, only you can shield me from the unforeseeable nightmarish future. Come and witness the beauty of my restricted territory and use it for your good, but please be wise! Let me breathe more for years in this splendid island while making you all the proudest.”
By Rtr. Hettige Indushika Anjanee
- Infographic Post By: Amana Anees
- Somaweera, R., Wijayathilaka, N., Bowatte, G., & Meegaskumbura, M. (2015). Conservation in a changing landscape: habitat occupancy of the critically endangered Tennent’s leaf-nosed lizard (Ceratophora tennentii) in Sri Lanka. Journal of Natural History, 49(31–32). https://doi.org/10.1080/00222933.2015.1006280
- Whiting, M. J., Noble, D. W. A., & Somaweera, R. (2015). Sexual dimorphism in conspicuousness and ornamentation in the enigmatic leaf-nosed lizard Ceratophora tennentii from Sri Lanka. Biological Journal of the Linnean Society, 116(3). https://doi.org/10.1111/bij.12610