Ecosystem quality (area) 1994-2017

Many qualifying species in sand dune ecosystems

Ecological quality is determined from the number of qualifying species (a selection of butterflies, vascular plants and breeding birds indicative of an ecosystem in a good condition) present in the area. By this measure, the ecological quality of almost 40% of the total area of terrestrial ecosystems is above average. In these areas more than half the maximum number of qualifying species are found in all management types (specific ecosystem types for which a certain conservation management regime applies). Open dunes contain the largest area with relatively high numbers of qualifying species and therefore have retained more of their flora and fauna than other ecosystem types. Natural and semi-natural grassland and marsh ecosystem types contain large areas with few qualifying species and therefore have on average a relatively low ecological quality.

Quality of forest ecosystems has improved the most

To investigate the changes in ecological quality, the period 2010-2017 was compared with the previous two periods (2002-2009 and 1994-2001). Marshes and natural and semi-natural grasslands show a net decline, but the quality of heath and open dune ecosystems appears to be stabilising. A bigger area of terrestrial ecosystems is increasing in quality than is decreasing in quality. This can be mainly explained by the large area of forest with a net increase in ecological quality; the average age of the forests is increasing, they are becoming more varied in structure and tree species composition, and more dead wood is now being left in the forest (see indicator CLO 0069, 1160, 1166), making forests a suitable habitat for more species. In addition, forests make up the majority of the area of terrestrial ecosystems (55%), which means they have a greater influence on the total score than other ecosystem types.

Besides this change in ecological quality (by area) there is a national trend in average ecological quality calculated from trends in the populations of species that are characteristic of the ecosystem.

• Trends in ecological quality, 1994-2017

High quality areas under pressure

Further analysis of the improvement and deterioration in ecological quality shows that in the period 2002-2009 ecosystems of poor to moderately poor quality on average improved, whereas ecosystem of moderately high to high quality on average deteriorated. It is apparently difficult to prevent ecosystems of good ecological quality from deteriorating. A possible explanation is that some areas of moderately high to high quality cannot be maintained with standard conservation management practices under current environmental conditions. In contrast, in the same period a larger area of low and moderately low ecological quality improved than deteriorated. It is probable that temporary or permanent restoration measures were taken in these areas.

Reasons for the limited area with a moderately high or high ecological quality

Land reclamation, agricultural intensification and a reduction in the influence of natural dynamic processes, such as flooding, erosion and sedimentation by the sea and rivers), have led to a decrease in geophysical diversity, and therefore also to a loss of ecosystem biodiversity. The high ecological quality in areas with many qualifying species is due mainly to the variation in water, environmental and land use conditions, which are caused, for example, by the presence of relief and dynamic landscape-forming processes. A greater degree of spatial connectivity and better environmental conditions where disturbing impacts of agricultural land uses and other activities are kept at a distance also helps to improve ecological quality. Furthermore, there are also regional differences in environmental impact, and ecosystems on nutrient-poor sandy soils are much more sensitive to eutrophication and acidification than those on clay soils. All these factors have a major influence on the presence of qualifying species and therefore on the variation in ecological quality.

• Spatial conditions of the national ecological network, 2021
• Environmental quality of surface water and natural areas, 1990-2010

Ecological quality a measure of policy success

The provinces and national government together have the task of realising the national objectives. In line with global objectives (CBD) and the EU Biodiversity Strategy, the overall goal of Dutch nature policy is to halt biodiversity loss. Under the Nature Pact (EZ, 2013) the national and provincial governments have agreed to improve ecological quality within the national ecological network by intensifying efforts to ensure adequate and regular conservation management activities enhanced by temporary or permanent restoration measures to improve water quality and environmental conditions. The above indicator shows that on average ecological quality is improving, but also that this is due mainly to the forests and that no other ecosystems show this average improvement in quality.

The provinces and conservation managers have developed a common lexicon for monitoring management types: the Nature and Landscape Index. This lexicon is part of the provincial 'monitoring and evaluation methodology' (WMBN) for national ecological network and Natura 2000/PAS (Van Beek et al., 2018). The methodology describes abiotic and biotic parameters used to determine the ecological quality of management types and areas. This indicator provides information about the quality of ecosystems and the changes in quality similar to the biotic parameter of the methodology. It thereby also gives an indication of the progress being made towards the general aim of halting and reversing biodiversity loss. However, the national government, the provincial governments and conservation managers have not made any agreements about the level of ecological quality to be achieved.

• Nature types in the Netherlands, 2023