By Anthony Shantikumar Perumal
Biodiversity comprises the variety of life on earth, and is another term for biological diversity categorised under three sectors:
- Genetic diversity
- Species diversity
- Ecosystem diversity
Genetic diversity
This is the result of a combination of different genes found within a population of a single species, which also includes the pattern of variation found within different populations of the same species.
Species diversity
It is described as a group of organisms with the capability of interbreeding and producing fertile offspring. Therefore, species diversity is the effective number of different species that are found in a collection of individuals.
Ecosystem diversity
This comprises all the different habitats that are sustained in tropical/temperate forests, hot/cold deserts, wetlands, rivers, mountains, coral reefs, etc. Each ecosystem provides complex relationships between plants and animals and other natural components that include sunlight, air, water, minerals, and nutrients.
Sri Lanka is an island that has a wide range of topographical features and has been identified to sustain a high proportion of endemics in its fauna and flora.
In comparison to the size and geographical features of India and Sri Lanka, our country has a higher proportion of endemism in certain species than India.
Endemics are species that are restricted to a specific geographical location and are not found elsewhere in the world. In the context of our country a higher proportion of endemics has been identified in the wet zone and the South western region of our island.
Point endemic species
These species are native to a certain limited eco system. Among the examples are the “Hara Wel” plant found in the Wathurana wetland forest and Puntius bandula that abound in the Galapitamada area.
Endemism of taxonomic groups recorded in Sri Lanka
| Taxonomic Group | Number of Species Recorded | Number of Endemic Species |
| Angiosperms | 3154 | 894 |
| Mammals | 124 | 21 |
| Reptiles | 209 | 125 |
| Amphibians | 111 | 95 |
| Birds | 453 | 34 |
| Freshwater fish | 91 | 50 |
| Butterflies | 245 | 26 |
| Freshwater crabs | 51 | 50 |
Source: The National Red List Sri Lanka
Keystone species
There are some species that play a unique and important role in ecosystem functions. Consequently, their removal will cause changes to the entire system. One such group is identified as “Keystone” species.
It is a species that has a disproportionately large effect on its environment relative to its abundance.
Such species play a critical role in maintaining the structure of an ecological community. A specific example is the elephant.
Flagship species
This species is one that is charismatic and selected to act as an icon or symbol for a defined habitat to ensure conservation. This is a human preference and is not scientifically based. Examples are the Sri Lanka blue magpie in the Sinharaja Forest Reserve and the leopard of Wilpattu National Park.
Importance of biodiversity
- Production of food
- Provides medicinal resources and pharmaceutical drugs
- Regulates the equilibrium of ecosystems
- High aesthetic and cultural heritage value
- Reduces the impact of natural disasters such as floods
- Decreases air pollution and greenhouse gases
Therefore the conservation of our forests and the ecosystems in them should be of paramount importance. It is imperative to sustain our biodiversity and the endemics that cannot be replicated or replaced for the depredation in their numbers by destruction of habitats will result in the extinction of the species.
(The writer is a longstanding member of the WNPS, has a Diploma in Zoology and a Diploma in Conservation from Centre of Excellence Manchester, UK)
The history of wildlife protection in Sri Lanka is almost synonymous with that of the Wildlife and Nature Protection Society of Sri Lanka. At 128 years old, the WNPS is the third oldest non-governmental organisation of its kind in the World and was responsible for the setting up of the Wilpattu and Yala National Parks in Sri Lanka, and of the formation of the Department of Wildlife Conservation
