Loss of biodiversity and pressures on ecosystem services are among the most pressing global environmental challenges. Changes in land cover and land use are the leading contributors to terrestrial biodiversity loss.

The OECD headline indicator on land cover change tracks conversions to and from natural and semi-natural vegetated land (like tree-covered areas, shrubland and grassland) to more anthropogenic and intensively used land cover types (like cropland and urban areas) on the basis that these conversions are likely to increase pressures on biodiversity.

An acknowledged limitation of such a high-level indicator is that it is difficult to estimate the benefits or costs (in terms of biodiversity or other ecosystem services) of identified land cover conversions. It is a crude proxy. This is partly because there is always a context-dependent correspondence between land cover class and biodiversity value; and partly because there are technical limits to the level of detail with which land cover can be currently characterised via remote sensing.

An option to help mitigate this limitation is to complement these indicators using datasets that identify a single type of very high-value ecosystem and monitor their status. Losses or gains of these ecosystems are less ambiguous and context-dependent and therefore easier to interpret. Intact Forest Landscapes are an example of a high-value ecosystem that can be (and are) monitored.

An Intact Forest Landscape (IFL) is an unbroken expanse of natural ecosystems within the current forest extent, with no remotely detected signs of human activity, and large enough that all native biodiversity, including viable populations of wide-ranging species, could be maintained (Potapov et al. 2017).

'Intact Forest Landscape Extent' is the extent of forest areas that are larger than 500km2, wider than 10km, free of settlements or infrastructure and unaffected by industrial activity, agricultural clearing or other anthropogenic disturbance in the last 70 years. Treeless areas within forests such as lakes, ice or patches of grassland are included.

'Intact Forest Landscape Degradation' occurs when some disturbance effects a forest area to the extent that the above conditions are no longer met.  

With the exception of degradation due to fire, the specific cause of degradation is not explicitly recorded however a sample-based analysis of intact forests degradation was conducted. The analysis reveals that logging is the greatest human driver of intact forest degradation globally and by far the greatest cause of degradation in Africa, Southern Eurasia, Southeast Asia and temperate and southern North America. Agriculture (followed by logging) is the primary driver of degradation in South America. Fire is dominant in North American and Eurasian Boreal forests. Energy, mining and transportation are the remaining major drivers, accounting for a share of degradation almost everywhere. Logging is observed to often be the first major human use that leads to a ‘cascade' of other uses (Potapov et al. 2017).

A little over half of global forest loss (by area) (but less than 10% of tropical forest loss) from 2000-13 is estimated to have occurred naturally from wildfire, pests and wind damage and would be expected to regenerate naturally. See Potapov et al. (2017) for more details.

Calculation method

The vector IFL maps distributed by the dataset authors are intersected with the FAO GAUL Administrative boundaries in a GIS and the intersecting areas calculated.

Notes

• Intact forest landscapes are transboundary therefore degradation in a neighbouring country or region can leave forest fragments on the other side of a border too small to meet the IFL definition (500 km2). This would be recorded as a degradation even if there has been no disturbance directly in that region.
• Dating fragmentation (i.e. identifying when certain infrastructure was built) is difficult - it is possible that fragmentation identified in 2013-16 actually occurred prior to 2013.