Red List Indicator, 1995 - 2015

Endangered and non-endangered species

The number of endangered species on the Red List can be regarded as an indicator for the state of the biodiversity in the Netherlands. The more species on the Red List, the worse the condition of nature and vice versa. Between 1950 and 1995, the number of endangered species has risen dramatically (see first tab page). More than 1/3 of all species gained Red List status during this period because they were endangered to some extent.
The number of endangered species has risen marginally between 1995 and 2005, but has in fact declined somewhat after 2005.

RLI length and RLI colour

The so-called "Red List Indicator" (RLI) reflects changes in the number of species on the Red List and the degree to which they are under threat. There are two RLI versions: RLI "length" and RLI "colour". RLI length (see second tab) indicates changes in the number of species on Red Lists by means of indices, reference year (1995 =100). If the Red List becomes longer (more species endangered), relative to the reference year, the value will exceed 100. If the number of endangered species is reduced relative to 1995, the RLI value drops to below 100. In other words - the lower the value, the better.
Species on the Red List can be classified according to the degree of threat they are exposed to. The RLI colour (see third tab page) also considers shifts between the various RL categories. For this RLI version, too, a lower value (= less "red") is better. On average, since 1995 more species have shifted towards the less-endangered categories than to the more-endangered categories. The changes are only small and dominated by vascular plants, as this is a very comprehensive group.

Groups of species

Taking separate groups of species into consideration, (fourth tab page), we find that improvement is not restricted to vascular plants: since 1995, mammals and dragonflies have also improved (see index values below 100 in 2015 in the table). Although average threat status in 2015 of breeding birds and reptiles improved to some extent compared to 2005, the number of threatened species of these species groups is still the same (and higher compared to 1995). Other species groups show very little or no signs of recovery compared to 1995 Red List status.
The RLI represents averages. So after 2005, the Red List status of many species has deteriorated, but the Red List status of an even larger number of species has improved; 28 "vulnerable" and "sensitive" species have improved and 19 have deteriorated. Eight species "seriously threatened" of "threatened" in 2005 have deteriorated further, but 33 species have improved. In effect, the most severely threatened species have improved in status in recent years. In addition, 11 species re-appeared, whereas only 3 have disappeared after 2005.

Representativeness

Nature policy and land management predominantly focus on the seven groups of species on the RLI. These groups have the greatest resonance with the wider public. Unfortunately, the RLI represents mainly terrestrial and fresh water species. Apart from a few sea mammals, marine species are lacking entirely.

Relevance for nature policy

During the past two decades, policy was aimed at averting the loss of biodiversity. Emissions considered harmful to the environment were reduced on a large scale and in many areas measures were taken to restore nature values (PBL, 2016). The area where nature is protected has grown and environmental conditions and water quality have improved.
The improvements may have contributed to the return to the Netherlands of a number of previously disappeared species. The improved water quality of rivers may have facilitated the return of the river clubtail, and recovery of calcareous grasslands may have facilitated the return of the Glanville fritillary. Other species have been actively reintroduced, such as otter and scarce large blue.
After many years of loss of biodiversity or - at best - a slowdown of the deterioration process, it seems that the number of threatened species in the Netherlands starts to get smaller. Whether this improvement is the result of measures taken in the past is subject to further investigation. The RLI criterion agrees with the international conventions ratified by the Netherlands, in particular the Bern Convention, the Convention on Biological Diversity and the EU biodiversity target. These conventions aim to prevent the loss of indigenous species at the national level.
In recent years, the Ministry of Economic Affairs has incorporated the RLI in the report to the parliament explaining the national budget, as an indicator of change in biodiversity.