Habitat Connectivity

Spatially isolated and small populations face an elevated risk of local extinction due to increased vulnerability to edge effects, genetic depletion, and random environmental events (see also Metapopulation and Island Biogeography Theory; Nentwig et al. 2017). This issue also impacts animal and plant species within protected areas, which are often limited in size. To counter these risks, the habitat-connectivity-concept (“Biotopverbund”) is a conservation strategy that promotes connectivity of suitable habitats in a landscape matrix, facilitating the movement of individuals between isolated populations. With climate change, the habitat connectivityis becoming increasingly important as it supports the necessary range shifts for species both within and beyond their current habitats. Since 2002, the habitat-connectivity-concept (“Biotopverbund”) has been established as a conservation goal under the Federal Nature Conservation Act (BNatSchG).

Connecting populations within core areas of habitat networks (often protected areas) is primarily achieved through linear dispersal structures (connectivity elements). Classic examples include flowering strips, field margins, hedges, deadwood hedges (“Benjes hedges”), and green bridges. Additionally, steppingstone habitats play a significant role, especially for mobile species. The effectiveness of these dispersal structures varies depending on factors like their size, habitat functions (dispersal and habitat roles), and the surrounding landscape matrix, which influences how well they meet the needs of different animal and plant species (Drobnik et al. 2013). Therefore, specific conservation strategies designed to connect isolated populations using suitable dispersal structures adapted to target specific species are particularly promising (see, for example, the Wildcat Corridor Plan of the BUND; www.wildkatzenwegeplan.de). However, designing suitable connectivity measures for less mobile habitat specialists, such as flightless insects and reptiles, presents greater challenges than for highly mobile species. Therefore, criteria for the systematic selection of target species are especially critical in such projects.

The challenge of implementing habitat connectivity involves achieving a balanced consideration of core areas, connectivity elements, and a suitable landscape matrix. This requires not only an ecologically robust approach, but also a comprehensive conservation strategy that addresses the diverse aspects of landscape planning.

Photo Gallery

Sources

Drobnik, J., Finck, P., Riecken, U. (2013): The Importance of Corridors in Implementing Cross-Border Habitat Connectivity in Germany. BfN-Skripten 346: 1-81.

Nentwig, W., Bacher, S., Brandl, R. (2017): Ecology – Compact. 4th Edition. Springer Spektrum, Heidelberg.