Connectivity and protected areas
Networks of protected areas such as Natura 2000 were established on a broad scale across Europe, but fragmentation and global change challenge species persistence in such rigid networks. Connectivity between networks can be promoted either by creating corridors or intervening “stepping stones” enabling individuals to move between habitat patches more regularly and reliably. Such movements typically constitute dispersal, but also anything else that may allow genetic exchange. However, the correct dimension of connectivity remains challenging.
What is the first thing that comes to mind when reading the word 'connectivity'? Is it perhaps 'corridors'? For some people the answer might be 'yes', because corridors can easily attract one's attention, especially in the innovative form of 'ecoducts' or 'eco-bridges' (Fig. 1). However, there has been a running debate for several decades regarding the cost effectiveness of corridors, asking what would be their best design and management, and in which circumstances do they really maximise the ecological benefits for species (Simberloff & Cox 1987; Beier & Noss 1998). To understand the debate, one must acknowledge that connectivity encompasses a much broader range of elements than just corridors. In this module we
Figure 1: Two examples of wildlife bridges or 'ecoducts', one in Banff National Park, Canada (left), and one in Borkeld, the Netherlands (right). Source: http://hiddenunseen.blogspot.de/2012/07/wildlife-overpasses.html
Beier, P., and R. F. Noss. 1998. Do habitat corridors provide connectivity? Conservation Biology 12:1241-1252.
Simberloff, D., and J. Cox. 1987. Consequences and costs of conservation corridors. Conservation Biology 1:63-71.