Species in the Netherlands under pressure from stress/environmental stress, 1950-2000
Decrease in taxonomic groups in the Netherlands
The natural environment in the Netherlands deteriorated sharply in the 20th century. The graph shows the decline (as a percentage) for a number of taxonomic groups compared to 1950 (RIVM, 2000). No distinction is made on the basis of cause:
total stress includes not only environmental factors but also fragmentation and the absence of management.
The term 'environmental stress' refers to the declines as a result of environmental factors only.
- See the 'overview of environmental themes and impact on nature', for an extensive discussion of the relationship between environmental considerations and the impact on nature.
Explanation of stress and environmental stress
The term 'environmental stress' was introduced to express in quantitative terms how species react to changes in environmental quality. The prevalence of species is compared with the situation in 1950. If there has been a decline, e.g. in the number of places where a plant species is found compared with the number of places in 1950, this is interpreted as being the result of stress. The part of the stress that can be traced to changes in the quality of the environment is referred to here as environmental stress.
For example: If the prevalence of a species has remained the same or increased since 1950, it is assumed that this species is not subject to stress (Vonk et al., 2001). If the prevalence of a species has declined by 50% since 1950, environmental stress is considered to be 50%.
The figure above shows, among other things, that the decline of the flora and fauna in bog pools is affected more by environmental factors (environmental stress) than by other factors. However, in the case of butterflies, the part played by factors such as fragmentation and mismanagement is at least as significant as that played by environmental factors.
