Ceylon Journal of Science 46 (Special Issue) 2017: 19-31 DOI: http://doi.org/10.4038/cjs.v46i5.7452 RESEARCH ARTICLE Role of human agency in the transformation of the biogeography of Sri Lanka P. Wickramagamage* Department of Geography,University of Peradeniya, Peradeniya, Sri Lanka. Received: 20/11/2016; Accepted: 18/03/2017 Abstract: The area referred to as the ‘Central Highlands of Sri the Wet Zone of Sri Lanka are separated by a dry lowland Lanka’, despite being the venue of a thin scatter of ‘Stone Age’ plain, it might have acted as a barrier to dispersal of plants human settlements was sparsely populated by man throughout and animals (Bossuyt et al., 2004). It should also be noted the island’s ‘Pre-Modern Era’, and much of it, especially at its that the climate of this area may not have been similar to higher elevations remaining under primeval forest cover. In what it is today during the last glacial period. Based on the late medieval times when this highland area became a part of present climate, the authors referred to above conclude that the ‘Kandyan Kingdom’, its forest-clad localities, except those the Wet Zone of Sri Lanka could be considered as an insular that were appurtenant to village settlement ecology, tended to be biogeographic region with its distinctive characteristics. strictly protected under royal decree. The island’s elevation ranges from the sea level to The cultivation of coffee on large areas of land – over 2,500m, with a range of microclimatic sub-regions. ‘plantations’ or ‘estates’ –commenced as a major economic Associated with these microclimatic regions are diverse enterprise after the establishment of British rule over the island ecosystems. The highlands were endowed with extensive in the early 19th century. This invariably entailed the extensive forest cover with limited interference by humans up to the clearing of forests. The ‘Ferguson map’ that depicts the colonial period. The highland forests are divided into sub- coffee estates that existed in 1863 and 1880 provides valuable montane (1000-1500) and montane (>1500m) forest types. information about the distribution of coffee plantations. In addition, there are two types of grasslands known as The present study is a product of an attempt to determine the Dry Patana and Wet Patana. The former is found in most location and the extent of coffee plantations in relation to climatic zones, whereas the latter is confined to the wet vegetation zones, administrative districts, and river basins of the areas. Central Highlands. It indicates, inter alia, the main plantation The status of forest cover at the time of British annexation area in the Upper Mahaveli catchment, and in the sub-montane of the Kandyan Kingdom and the events thereafter could zone. The second largest extent was in the Kelani Basin. Clearing be traced from many literary sources. These information of forests led to erosion of hillslopes, siltation of riverbeds sources include contemporary writings by explorers, and the low-lying areas, particularly in these two river basins. environmentalists, and visitors, etc., statistics compiled by Within a period of 50 years the landscape of a large part of the the colonial rulers, and cartographic products. Although Central Highlands was transformed from forest-covered hills proper mapping of the island started at the beginning of to a landscape dominated by plantations. This process caused the 20th century, two map compilations of the coffee estates irreparable damage to the biodiversity of the montane and sub- based on survey plans are available. These maps provide montane areas of Sri Lanka.Keywords: endemism, evolutionary very precise information about the extent and location of stable unit, mammal subspecies, habitat quality, ecological niche, the individual estates, in the highlands of Sri Lanka. The mammalian evolution. impact of human interventions can also be gleaned from Keywords: Prehistory, colonial, deforestation, coffee, montane, reports prepared by various commissions appointed by the sub-montane. colonial administration to address serious environmental consequences of plantation agriculture and environmental concerns highlighted by environmentalists. This study INTRODUCTION analyses the information available from a representative From a diastrophic perspective the island of Sri Lanka sample of these different sources to understand the scale of lies in the Indian plate in close proximity to peninsula deforestation in the highlands after the fall of the Kandyan India. Sri Lanka and India share the same continental Kingdom in 1815 and up to the end of the coffee industry shelf and the former is therefore a continental or a shelf in 1880s. island. Unlike oceanic islands, Sri Lanka has had on and In order to determine the ecological impact of colonial off connection to the subcontinent allowing the dispersal rule, it is imperative that we establish a baseline by of organisms in the geological past. Western Ghats and reviewing the information relating to human activity in Sri Lanka are designated as a single biogeographical unit this region during prehistoric and historic periods, which which first identified by Wallace (1876). However, as preceded the colonial experiment. This paper is a re- noted in a recent study since the moist Western Ghats and interpretation of all the available information to evaluate *Corresponding Author’s Email: [email protected] http://orcid.org/0000-0002-6251-538X 20 Ceylon Journal of Science 46 (Special Issue) 2017: 19-31 the process of deforestation and its impact on Sri Lanka. THE MONTANE AND SUB-MONTANE AREA Another important aspect of ecological impact of colonial The montane and sub-montane areas are defined on the rule is the introduction of new species to the highlands. basis of the elevation alone. The area within 1000 -1500 This has been dealt with in detail in other works (Webb, m is the sub-montane and above 1500 m is montane. The 2002). total extents of the sub-montane and montane regions are 176,455 ha and 80,163 ha respectively. Both these units DATA AND METHODOLOGY fall within the Wet and Intermediate climatic zones. The The data and information used in this analysis include montane and sub-montane elevation zones act as important secondary data available in the form of historical maps, upper catchment areas of the major rivers of Sri Lanka statistics, government records and textual sources. Based (Figure 1). The highest elevation of the montane zone on the block out plans prepared for land sales, a map was is 2,534 m at Pidurutalagala peak. Since elevation is compiled and published by the Ferguson Ceylon Observer decidedly the most important determinant of the island’s Office (1880). This map shows the coffee estates that climate and water resources, it is important to note that existed in 1863, and those developed between 1863 and rains brought by the two monsoons have much to do with 1880. The scale of this map is one inch to two miles. the position of the small but very important highlands in Another map based on the surveys carried out for land the south central part of the island. alienation to planters was compiled by Arrowsmith in 1862, The topographic variation of this small area is also a which is commonly known as the Fraser’s Map. Both maps factor in the great variability of the climate and ecology of depict estate boundaries, but the Frazer’s map also carries the island. Figure 2 is a plot of the elevation vs. the land the names of the estates. Several researchers have made area above that elevation, and it shows that the area above references to these maps (Baranage, 1983, Roberts, 1970), 500m contour is only just over 9% of the total area of the but no one has studied them quantitatively in relation to island. The extent of the montane and sub-montane areas the location of coffee estates in different environmental and combined is only about 4% of the total land area of the administrative settings. In the absence of any other sources island. The agroecological diversity of the region is shown of locational information on the coffee estates of Sri Lanka, by the presence of 22 agroecological regions within the the Ferguson map provides invaluable information on the area above 1000m contour (Punyawardene et al., 2003). spread of coffee plantations in Sri Lanka. As this map does not have the coordinate grid printed on it, geo-referencing RESULTS AND DISCUSSION of the map was done based on modern 1:50,000 maps. Additional data were extracted from Sessional Papers of Status of the Pre-colonial Forest Cover of the Highlands the Legislative Council of Ceylon, and Blue Books of the th The available evidence shows that the montane and sub- 19 century. These sources provide data on land sales, montane forests of Sri Lanka were not free of human cultivated area, etc. The contemporary writings also th interference in ancient times, but the impact of these helped to determine the extent of deforestation in 19 interventions would have been rather limited to clearing century Ceylon (Sri Lanka). From the georeferenced of small patches of forest at a time. The earliest evidence image of the coffee plantations map, the estate boundaries of human presence in the highlands goes beyond the Last were digitized and the extent of each estate was calculated. Glacial Maximum (LGM) about 18,500 years ago. The The map shows coffee estates as belonging to two time distribution of pre-historic habitation sites, can be used as periods, 1830 to1863 and 1863 to1880. It depicts all the an indicator of some form of deforestation. A map was coffee estates that existed at that time, except 38 estate compiled based on the pre-historic sites mentioned in the properties covering approximately 3,159 ha (7806 acres) literature (Figure 3).