DISCUSSION |
Forest history of Uttara Kannada reveals that shifting cultivation was a decisive force that altered the primary forests substantially, creating vast stretches of secondary forests. The early agricultural communities, however, left behind a great legacy of sacred forests (kans) in Uttara Kannada and other adjoining districts. Many of these kans to this day are relics of the primary forests of the Western Ghats and are centers of endemism for both plants and animals. Myristica swamps are associated with some of these sacred forests [1,12,27,28]. These relics lost their special identity as sacred forests and got merged with the state reserve forests during the British administration [27]. Subsequently, they were subjected to commercial timber harvests, tree monocultures, etc. In many places, the kans were cut down for expansion of cultivation or converted into leaf manure forests or subjected to other kinds of human impacts [28, 29].
Our finding of Dipterocarpus in Ankola (14.7° N) goes to substantiate Caratini et al. [33], who have reported the presence of its pollen in marine core samples close to Kali River estuary (14.8° N). This is incidentally range extension of present distribution of Dipterocarpus towards north by 30km. The Dipterocarpus patch in Ankola was obviously part of a sacred kan forest. A small Myristica swamp is also associated with it. Same could be stated about Syzygium travancoricum, a stately tree, thought to be extinct once, but rediscovered later, only in southern Western Ghats. Our findings of this critically endangered tree in Siddapur of Uttara Kannada and a single individual in Ankola, in forest patches of ancient antiquity, is very significant. The Siddapur relic forests are also home to recently discovered new tree species Semecarpus kathalekanensis [2]. However, biologists should restrain themselves from the general tendency of naming any apparent novel occurrences of plants or animals that they might come across in relic forests as new species; these could as well be the relics of ancient populations or their morphological variants.
The occurrence of Madhuca bourdillonii and Syzygium travancoricum in Uttara Kannada forests of central Western Ghats, along with Myristica swamps and Dipterocarpus, clearly goes to prove that low altitude climax evergreen forests with the entire gamut of endemic species of flora and fauna, had more northern ranges for their distribution. Their present day disjunct distribution is largely on account of human impacts on the primeval forests, which have been largely wiped out. Several authors also consider that the current discontinuity of some faunal species in India, might represent relics of a former continuous distribution [34-37]. Karanth [38] considers climatic change and deforestation might be the major causes for present day disjunct distribution and aggregation of the endemic and endangered primate lion-tailed macaque (Macaca silenus) in the relics of wet evergreen forest patches of the South Indian Western Ghats.
The view is strengthening among the conservationists about the importance of protecting also smaller patches of forests in the tropics that lie outside large reserves as a substantial number of forest species can persist for decades in fragmented forest [6,38-40]. Inevitably, small fragments will become the last refuges of many rainforest species that are on the brink of extinction, despite the proneness of such populations suffering from depressed reproductive outputs [41]. It is in some such fragmented forests that we have observed the critically endangered species Madhuca bourdillonii and Syzygium travancoricum.
What is of grave concern for conservationists is the casual attitude with which the Western Ghat forests are managed, nearly oblivious of their ecological history. Bulk of the primeval forest fragments, in whose conservation the precolonial farmers appear to have played key role have perished during the period of modern forestry, whose foundations were laid by the British. Foresters and ecologists should be able to distinguish between relics of primeval forests and advanced stages of secondary successions. Lack of this perception would result in the silent extinctions of scores of endemic species. Madhuca bourdillonii in Uttara Kannada is on the verge of extinction on account of unsatisfactory reproduction as well as human and predatory pressures. We are hopeful that more such relic patches with their valuable biota might be in existence in between Travancore and Uttara Kannada.
