The Natural Capital Index of the Netherlands
The indicator Natural Capital Index (NCI) entails both the changes in "nature quality" as the change in area of ecosystems. The NCI of the Netherlands has fallen sharply, not only because of a decline in the "nature quality" but also because of the decline of natural areas in the last century.

What is the NCI?
The Natural Capital Index (NCI) is an indicator for the biodiversity of habitats. NCI considers biodiversity of an ecosystem as the stock of its characteristic species including their corresponding abundances. The loss of biodiversity is characterized by the decrease in abundance of many species and increase of a few others, due to human interventions. NCI is a function of changes in the area of ecosystems and the changes in abundance of a core set of species within the remaining ecosystem. The latter is called "nature quality", the former factor "ecosystem quantity".
Trends in "nature quality"
The "nature quality" of the natural ecosystems in the Netherlands varies from 30% to 50% (see left-hand figure). On average, the quality is 44% compared with the low impact baseline state. This means that the species abundance is on average 44% compared to the baseline state The "nature quality" of the agricultural area is 36% (not shown in the figure).
"Nature quality" has declined most in forest and woodland, heathland, lakes and pools, fresh water in the river region, and in the saline delta. The highest nature quality is found in marshes, swamps and bogs, the dunes, the freshwater delta in Zeeland, and the Waddenzee (Wadden Sea).
Trends in natural capital
Combining all the natural ecosystems allows the Natural Capital Index for the Netherlands to be calculated. Given an average "nature quality" of 44% and a proportion of the area that is 41%, the NCI for the entire country in 2000 was 18%. The NCI for 1900 and 1950 were 55% and 30% respectively (see left-hand figure).
Causes
The decline in NCI is the result of human activities, particularly the eutrophication, acidification, lowering of groundwater tables, fragmentation, overexploitation and last but not least habitat loss in the 20th century.



