IENE 2016

This presentation focuses on fish that use fresh-water systems and provides solutations to minimise the effects of roads and road-stream crossings on fish and fish habitat. In order to complete their life cycles, fish need to move throughout waterways in their range to reach their spawning grounds, rearing areas or food resources. Streams providing necessary habitat are often in close proximity to or crossed by roads and railways, which can lead to habitat degradation and barriers fish movement. By degrading and isolating habitats, barriers can decrease fish populations and in some cases contribute to the total loss of a species.

Steps typically taken to create and protect roads near streams include straightening channels or placing very large rocks or concrete reinforcement to stabilise banks. These generally result in loss of habitat and potential impacts to fish and wildlife populations. The dynamic character of streams and rivers and their changing nature needs to be accommodated in planning, expanding or operating transportation infrastructure where roads and other linear infrastructure cross water or occur in a floodplain. This is necessary not only to minimise direct ecological effects to habitat and fish, but also to help reduce the potential damage to infrastructure from flooding, erosion and channel movement. Damage to infrastructure can often lead to additional environmental impacts. New infrastructure should avoid waterways where feasible and any crossings that are needed should be designed to allow the natural flow and function of the waterway. Existing road crossings that are barriers to the movement of fish should also be modified to be more natural and improve connectivity for fish and the support of natural stream function.

This abstract is based on two chapters which recently have been published in Handbook of Road Ecology (Van der Ree, Smith and Grilo edt., 2015). This involves chapter 44 'Form and function: a more natural approach to infrastructure, fish and stream habitats' written by Paul Wagner and chapter 45 'Solutions to the impacts of road and other barriers on fish and fish habitat' written by Fabrice Ottburg and Matt Blank.