Islands constitute a special class of ecosystem management. On an island, like Sri Lanka, wildlife populations are constrained, and wild areas are limited by the size of the landmass. Because wildlife populations are unable to disperse beyond the island’s boundaries, their collective ability to adapt to changing conditions are limited. For most species, the influx of new genes from an outside population is extremely unlikely, making the conservation of the existing gene pool that much more important.
Added to this is forest and wilderness fragmentation, which exacerbates this scenario; making remaining pockets of forests islands within an island. In this backdrop, ensuring that the remaining forest lands in Sri Lanka remain connected are vital, if we are to continue to be a biodiversity rich nation.
Sri Lanka is a relatively small island - just 65,610 km2. As such, it is important that the wild lands that still exist do not become irreversibly fragmented. Unfortunately, the forest cover of this island has been reduced from 80% to ~20% in the last 80 years, due to large-scale clearing of forests for tea plantations, water dam projects and development. The consequences of this have been deforestation of the land and the continuing fragmentation of the landscape, creating patched forests. Of the ~20% of forest land left, only 12 – 15% of it is under state protection. These forest patches exist in a mosaic-like pattern across the island, with potentially hostile habitats between them, possibly isolating wildlife populations and affecting species richness and population sizes. This isolation reduces species interactions, creating a loss in genetic diversity which is vital for species survival. Therefore, understanding how local wildlife use these forest patches as refugia and how they adapt to these human-induced changes, is essential to any conservation effort.
The WWCT’s Patch Forest Project works to establish the important role that these small patch forests play for the Sri Lankan leopard, as well as the island’s three other wildcats – the fishing cat, the jungle cat, and the rusty-spotted cat – as dispersal routes and stepping stone refuges between the larger, protected forest landscapes. This project also provides us with the opportunity to collaborate with the landowners of patch forests, so they too can understand the role their land could be playing in the larger system, and to improve the overall habitat for wildlife.
The WWCT has been conducting research on Central Highland patch forests such as the Dunumadalawa Forest, Kandy; Agra Arboretum, Agrapatana; Duckwari patch forest, Matale and Dunkeld Estate, Dick Oya. Dry zone patch forests in the Gal Oya complex, Dehigaha Ela and Pidurangala, in Sigiriya.
Outside of the protected lands, a matrix of vital connector mixed land-use and wilderness remains, within the extensive plantation lands, home gardens, and other crown-owned land. Most wildlife populations are not averse to using these connections to move between secure populations in the larger forest areas. The importance of these connections cannot be overstated for the long-term conservation of individual species, to prevent the fragmentation of wildlife populations, and to maintain a robust ecosystem. Identifying these Corridors for Conservation, which can also be additional refuges, for targeted protection and active regeneration is essential for Sri Lanka.
Such work in the Central Highlands Peak Wilderness area is ongoing with ridgeline Conservation Corridors such as the Peak Ridge Forest Corridor, Western Ridge Corridor and Elbedda Ridge Corridor being currently researched and collaboratively targeted for conservation.
Unlike large natural landscapes, human demarcated Protected Area (PA) complexes often have harsh edges, ringed by human habitation and agriculture, that are limiting for wildlife. These edges are areas in which humans and wildlife potentially come into contact, and present different challenges that can affect wildlife survival. A buffer zone, then, represents a more neutral space surrounding a protected landscape, where wildlife can move through low density human-populated areas, with relative safety.
Research in these buffer areas allows us to understand the impact of human expansion on the movement of wildlife, as well as the causes of any conflict that may arise here. Mitigating this conflict and promoting human-wildlife coexistence is key to the ultimate conservation and preservation of the wildlife on our island.
Our current work in the Buffer Zones of the iconic Ruhuna (Yala) National Park and Wilpattu National Park Buffer Zones attempts to document how leopards are dispersing here, the use of wildlife of these more marginal lands and the impacts of increasing degradation and human presence on this land. It also aims to integrate the communities that live in these important buffer areas.
The overall aims of our research in these different areas are:
To chart the actual extent of usable connector forest cover and wilderness connections within the island of Sri Lanka. (The actual ground situation of an area and its use by wildlife is often different to the existing charted maps).
To understand how fringe habitats and other land use areas, such as edge habitats of PA’s, plantations and riverine belts are utilized by wildlife populations.
Research of dispersal routes of subadults of selected species and their land use patterns.
The eventual protection of important forest corridors as connections – the ridge forest in the montane zone area above 6000 ft., and above the tea plantation zone is a focal point.
Documenting forest patch use by wildlife and leopards, as added refugia and stepping stones for movement and dispersal.