Ecosystem quality (area), 2012-2023

Many qualifying species in forest open dune ecosystems

An indicator for the quality of ecosystems is the presence of qualifying species. Qualifying species are plant and animal species characteristic of a certain type of ecosystem or habitat and which are used in Index NL (a typology of ecosystems integrated into ‘nature types’) to assess whether management types (subdivisions of nature types) have a good ecological status. The assumption is that the more qualifying species that are present in a management type, the higher the quality of that management type. Changes in the numbers of these species show whether the ecosystem quality of the area is improving or deteriorating. For this indicator the 49 management types are combined into five ecosystem types.

• Typen natuur in Nederland (Index NL)

The quality of ecosystems is determined from the number of qualifying species of butterflies and breeding birds, as sufficient distribution data are available for these two species groups. The indicator shows that almost 26% of the total area of terrestrial nature has a moderately high or high ecosystem quality. Forests, followed by open dunes, had the highest proportional area with a relatively high number of qualifying species. These areas have therefore retained most of their quality in terms of flora and fauna. The semi-natural grassland ecosystem consists mostly of large areas with relatively few qualifying species and so has a relatively low ecosystem quality. 

Quality of forest ecosystems has improved the most

To investigate changes in ecosystem quality, the period 2018–2023 was compared with the previous period (2012–2017). Overall, the quality of the majority of the area of terrestrial nature (80%) has remained stable. There was even a net improvement: the area of terrestrial nature where ecosystem quality has improved is larger than the area where it has worsened. This is mainly down to the relatively large area of forest (350,000 ha, 55% of the area of terrestrial nature), which shows an improvement in quality. This means that the improvement in the ecosystem quality of forests weighs more heavily in the final assessment.

The ecosystem quality or forests is improving because they are on average becoming more mature, with greater variation in vegetation structure and species composition, and that nowadays more dead wood is left on the forest floor, making forests a suitable habitat for more species. Ecosystem quality is not improving in all forests; the quality of forests on the higher sandy soils in particular remains unsatisfactory. These forests are relatively sensitive to high nitrogen deposition and desiccation. Open dunes also show a net quality increase. Succession is occurring locally, partly due to a reduction in rabbit populations. In addition, restoration projects have been carried out in recent years which have led to an increase in species richness in these areas (Van Dijk & Lok, 2020). 

• Ontwikkeling van het Nederlandse bos
• Areaal bostypen
• Fauna van bos
• Dood hout en bosbeheer

Another indicator of the quality of nature shows the average change in population size of almost all native breeding birds, reptiles, amphibians, butterflies and dragonflies, and most species of mammals and freshwater fish: 376 species in total. Population size is expressed in numbers or in the size of the species range. These trends are based on several species groups and are updated each year, making them more suitable for monitoring changes in quality over time.

• Living Planet Index Nederland

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

Land reclamation, agricultural intensification and a reduction in the influence of natural dynamics, for example in seas and rivers, have reduced spatial and temporal diversity and therefore also ecosystem biodiversity. A high ecosystem quality in certain areas is due mainly to the remaining variation in water, environmental and spatial conditions, for example due to the presence of relief and dynamic landscape-forming processes. A large degree of spatial connectivity and good environmental conditions in areas that are far from disturbing land uses and activities also helps to improve ecosystem quality. There are also regional differences in environmental impact, while 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 differences in ecosystem quality.

• Geschiktheid ruimtelijke condities landnatuur

Ecosystem quality a measure of policy success

In line with global objectives (CBD) and the EU Biodiversity Strategy, the overall goal of Dutch nature policy is to halt biodiversity loss. The recently adopted EU Nature Restoration Regulation requires EU member states to take restoration measures within and outside protected areas. In the Nature Pact (EZ, 2013) the national and provincial governments have agreed to improve ecosystem quality within the national ecological network by intensifying efforts to ensure sufficient standard conservation management activities and temporary or permanent restoration measures to improve water quality and environmental conditions. The above indicator shows that ecosystem quality is stable in the majority of the area. The area where quality is improving is larger than the area where it is declining.

Provincial governments and site managers have developed the NL Index to describe management types and to monitor and assess the quality of management types (Van Beek et al., 2018). The methodology describes abiotic and biotic parameters that can be used to determine the ecosystem quality of management types and areas. This indicator provides information about the quality of management types, combined into ecosystem types, and the changes in quality of the biotic parameter (qualifying species). It therefore also gives an indication of progress towards the general aim of conserving and restoring biodiversity. However, national government, the provincial governments and land managers have not made any agreements about the level of ecosystem quality to be achieved in the areas.