Case Studies
Case Study: Ecological corridors in ecological networks
This case study is part of the IUCN Guidelines for conserving connectivity through ecological networks and corridors illustrating initiatives around the world that are working toward maintaining, enhancing, and restoring ecological connectivity. See all case studies here.
Ecological connectivity in an urban context: Utrechtse Heuvelrug, Netherlands
By Rob H.G. Jongman, Independent Scientist and Chris Klemann, Province of Utrecht
Key lesson
Netherlands offers a model of ‘the polluter pays’ that helps finance connectivity, such as safe passage across roads, and allows activities compatible with connectivity goals (e.g. recreation) to occur in the corridors.
Context and challenge
Netherlands is a largely urbanised country and nature faces pressures from urban expansion, infrastructure, intensive agriculture and recreation. The Utrecht Hills (Utrechtse Heuvelrug) stretch from north-west to south-east and comprise several important nature reserves and a national park. This area is dissected by several motorways and railroad lines, which were making it nearly impossible for fauna to move through the landscape. However, the area is part of the Netherlands Nature Network. Therefore the province of Utrecht and the responsible nature management agencies, Utrechts Landschap (https://www.utrechtslandschap.nl/) and Goois Natuurreservaat (https://gnr.nl/), were mandated to restore connectivity for wildlife.
‘The polluter pays’ is a basic principle in environmental policy in the Netherlands. Therefore, the owner and manager of transportation infrastructure is responsible for financing and implementing all ecopassages (green bridges and culverts); the funds do not come out of the nature conservation budget. This is the main reason why ecopassages were not implemented in the 1990s. The district’s mandate to restore connectivity and lack of actions by the national road authorities (which have an implementation budget) created tensions. Coordination between national and provincial authorities was needed for realising necessary connecting measures for provincial roads for an optimal return on investments.
Approach
A renewed effort was made to speed up the process of landscape defragmentation through the Netherlands Nature Network, which consists of protected areas and the linkages between them, and a national defragmentation plan that came with extra funds. Both programs were scheduled for implementation from 2004 to 2018.
Figure 1. The West and East ecological corridors in the Utrecht hills. The numbers indicate motorways (red) and link roads (yellow). The blue names indicate built-up areas; purple: heathland; green: forest. © Provincie Utrecht
Examples of ecological corridors
For the province of Utrecht, priority measures were planned for the Utrecht Hills to improve wildlife movement across national motorways and railroad lines, which is a national responsibility. The province was expected to contribute to the plan by implementing defragmentation measures for the roads under their responsibility.
Accordingly, the province of Utrecht has elaborated plans and actions for the Utrecht Hills (http://www.hartvandeheuvelrug. nl/projecten/ecologische-verbindingen/). The project ‘Hart van de Heuvelrug’ consists of two main ecological corridors that merge in the north (Figure 1).
The western part of the project area is a forest corridor, with the eastern part a heathland corridor. Both corridors contain many small tunnels that cross under roads (such as a tunnel in the south-east of the province under road N225; https://www. youtube.com/watch?v=hHAn-Clwy8Q&feature=youtu.be). To realise connectivity, an additional five ecoducts have been built in these two ecological corridors, including the Ecoduct Op Hees (Figure 2), which was completed in 2013 and crosses a busy railroad line between the cities of Amersfoort and Utrecht. In addition to facilitating wildlife movements, it also serves as a recreation corridor. For this purpose, the ecoduct has been made wider to accommodate cyclists and pedestrians.
Figure 2. Ecoduct Op Hees, crossing the Utrecht–Amersfoort rail line. The recreation cycle path is situated at the foreground side of the bridge © ProRail
Results
The two ecological corridors act as movement routes for mammals (such as roe deer, Capreolus capreolus; badger, Meles meles; and tree marten, Martes martes) and as a temporary living and breeding area for smaller mammal species. Through these ecological corridors, plants and animals can spread and move from Gooimeer (Gooi Lake) in the north-west to the Veluwe National Park in the south-east.