The irreparable loss

Forests-Beyond The Wood - VII

by Dr. Ranil Senanayake-September 10, 2018, 9:31 pm 

Sri Lanka’s Rainforests can be traced back to the mountains of Gondwanaland some 20 million years ago. They moved across the island in response to climate changes through this time but because of the shape of the mountains always had refugia in the South Western quarter. The biodiversity developed as a response to the mountains acting as ‘islands’ during times of drought and desiccation. Thus, the rainforests contain elements of a relict fauna, once shared with Africa. The bizarre horned lizards of the Genus Ceratophora are an example.

These forests remained generally inviolate since their formation, the Sinhalese civilizations who maintained historical records going back over 2200 years do not indicate the use of the mountains and rainforests for settlement or agriculture. It was only towards the 15th and 16th centuries that the montane zone became populated, but even then, the only anthropomorphic landscapes of consequence were in the flood plains of the river valleys, which were turned into rice fields.

The Rainforests began to be impacted and the ‘’Continuous Forest’ landscape gave way to the ‘’Colonial’ landscape’ around 1700-1800. Forests were felled for timber export and plantation industry was in its infancy with small monocultures of Cinnamon. The large scale felling of forests began after 1820 when all land without title was deemed 'crown land' and sold to commercial interests in the West. The 'coffee boom' of 1835 was a rush for land that was only equalled by the rush for land during the gold discoveries in the U.S.

The early colonial landscapes saw the creation of new ecosystems or 'agro ecosystems' that usually had exotic organisms as the dominant species. They contained large areas of monoculture, first coffee, then tea, rubber and coconut; these ecosystems replaced the more diverse indigenous forms. Coffee and tea replaced montane forests, rubber replaced lowland rainforest and coconut replaced lowland rainforest and evergreen forest. A further problem with these crops was the fact that large quantities of firewood were required in processing for export. The source of firewood was from the forest ecosystems of the landscape. Thus this period saw a reduction of indigenous landscapes not only as a consequence of forest clearing, but also as a consequence of timber and firewood extraction. Much of the original agricultural endeavour at this time did not pay any heed to good management practices. Thus large areas began to loose topsoil, became impoverished and were abandoned to become fire maintained grasslands. Indigenous landscapes were transformed, the new landscape containing far less natural forest.

The late colonial period saw landscapes that were being managed to sustain some element of ecological stability. The lessons of land degradation were learnt early and sound land management practices were instituted. Shade trees, windbreaks, contour planting; terracing and draining began to emerge as management characters. Even at this time the loss of indigenous species and ecosystems was occurring,

The loss of rainforest biodiversity in the last two hundred years is incalculable. Simply in terms of soils alone the loss is not confined to nutrients and organic matter, the loss of species specialized for life soil ecosystems is suggested by the existence of a large number of genera and species of earth snakes, such as Rhinophis, Aspidura, Thyphops and Aspidura suggest the diversity of the ecosystems that they once evolved in.

Currently most of the existing patches of rainforest come under the purview of the Forest Department, which has already stated that ‘reaching the target of 32% of forest cover would be an impossible task’, in the face of ‘ongoing development activities particularly with launching new irrigation projects and improving the infrastructure with highways and expressways’. The forests they hold do not enjoy any protected status in law and could be designated ‘multiple use’ indicating that timber extraction or ‘development’ is a valid activity in these forests. Protection from timber extraction and clearing for ‘development’ must become a feature of such patches. All Rainforest Patches need to be identified and strict conservation status conferred upon them if the massive loss of biodiversity is to be slowed.

The rainforest has also left some relict populations on the eastern side of the land to remind of its once massive spread . The Dipterocarpus forest in Uda Kirawa at Lunugala in the dry eastern side of the central mountain is such a remnant fragment of the rainforest. Nestled between two mountain ridges such protected valleys have manged to retain much of the tree and shrub species, but due to the felling and clearing of the watershed has lost all of its native fish fauna. There are moves to restore this loss in a combined project with the Depts of Zoology, Forestry , Wildlife and the private sector, but many other fragments remain.

Thus the assessment of species within restricted or fragmented must be undertaken quickly. The recent fragmentation of the rainforests into small patches means genetic isolation and drift has already begun. This not only means local extinctions due to the ‘Island Geography’ effect come into effect, but also marked differences in their gene frequencies creating ‘chimeral’ patterns that are easily confused with new species. Thus, new non destructive methonds of mapping biodiversity within such patches needs to be developed as collecting and preserving specimens may lead to extinctions in small, isolated populaions. Confusing taxonomy with conservation may have serious national repercussions.

The conservation challenge is how to connect the isolated patches through the creation of corridors or by developing homegardens to be more ‘analagous’ or similar to the forest. In this manner it might be possible to win back some of the massive output of Primary Ecosystem Services (PES) that we lost with the destruction of our rainforests. The great rainforests of Sri Lanka are gone, can we think about a forestry programme that seeks to build back at least some of it and create space for native biodiversity within antropogenic ecosystems.

In our national effort to reach the goal of 32 percent of forest cover, we should appreciate what a forest is, so that we cannot be taken for a ride with all new ‘forestry’projects . This is a contribution seeking to inform that appreciation.

Conservation (picture courtesy: PTI)