Most of the world's original forests have either been lost to conversion or altered by logging and forest management. Forests that still combine large size with insignificant human influence are becoming increasingly important as their global extent continues to shrink.
There are several reasons to focus on large undeveloped forest areas:
- Ecosystems are generally better able to support their natural biological diversity and ecological processes the lower their exposure to humans and the greater their area. They are also better able to absorb and recover from disturbance (resistance and resilience).
- Large natural forest areas are important for the preservation of all strata of biological diversity. Fragmentation and loss of natural habitats are the main factors threatening plant and animal species with extinction. Large, roaming animals (such as forest elephants, great apes, bears, wolfs, tigers, jaguars, eagles, deer etc.) especially require that intact forest landscapes be preserved.
- Large natural forest areas are also important for maintaining ecological processes and supplying ecosystem services like water and air purification, nutrient cycling, carbon sequestration, erosion, and flood control.
- The conservation value of forest landscapes that are free from human disturbance is therefore high, although it varies among regions. At the same time the cost of conserving large unpopulated areas is often low. The same factors that have kept them from being developed, such as remoteness and low economic value, also help to reduce the cost of protecting them.
Protection of large natural forest landscapes is a highly important task to help fulfill different international strategic initiatives to protect forest biodiversity (CBD), to reduce carbon emissions from deforestation and forest degradation (IGBP, REDD) and to stimulate sustainable forestry management practice use (FSC). Mapping, conservation and monitoring of Intact Forest Landscapes is a therefore a task of great global significance. The concept of an Intact Forest Landscape (IFL) and its technical definition were developed to help create, implement, and monitor policies concerning the human impact on forest landscapes at the regional or country levels.
We define an Intact Forest Landscape (IFL) as an unbroken expanse of natural ecosystems within the zone of current forest extent, showing no signs of significant human activity and large enough that all native biodiversity, including viable populations of wide-ranging species, could be maintained. Although all IFL are within the forest zone, some may contain extensive naturally tree-less areas, including grasslands, wetlands, lakes, alpine areas, and ice. This definition builds on the definition of Frontier Forest that was developed by WRI (Bryant et al., 1997).
Technically, an Intact Forest Landscape (IFL) is defined as a territory within today's global extent of forest cover which contains forest and non-forest ecosystems minimally influenced by human economic activity, with an area of at least 500 km2 (50,000 ha) and a minimal width of 10 km (measured as the diameter of a circle that is entirely inscribed within the boundaries of the territory).
Areas with evidence of certain types of human influence are considered disturbed and consequently not eligible for inclusion in an IFL:
- Settlements (including a buffer zone of 1 km);
- Infrastructure used for transportation between settlements or for industrial development of natural resources, including roads (except unpaved trails), railways, navigable waterways (including seashore), pipelines, and power transmission lines (including in all cases a buffer zone of 1 km on either side);
- Agriculture and timber production;
- Industrial activities during the last 30-70 years, such as logging, mining, oil and gas exploration and extraction, peat extraction, etc.
Areas with evidence of low-intensity and old disturbances are treated as subject to "background" influence and are eligible for inclusion in an IFL. Sources of background influence include local shifting cultivation activities, diffuse grazing by domestic animals, low-intensity selective logging, and hunting.