RATIONALE. Habitat-related to transport infrastructure (HTI) management
Transport infrastructure include a vast quantity and diversity of natural habitats, the design and management of which can bring positive effects for biodiversity and people. While often strictly regulated for safety reasons, there are management solutions that can benefit biodiversity and also contribute to climate change adaptation (CEDR, 2016; Jakobsson et al., 2018; LIFE LINES, 2021). These areas are important elements of green infrastructure networks where the application of Nature-based Solution can contribute positively to surrounding landscapes ecologically, economically, and socially (EC, 2013; Blackwood et al., 2022).
Regarding green areas, selecting the appropriate species to be planted, adjusting mowing regimes, and developing alternative maintenance methods (Jakobsson, 2018; UIC, 2023) can increase ecosystem services such as pollination, at the same time enhancing richness of biodiversity and avoiding the spread of IAS and wildfires (François & Le Féon, 2020; LIFE LINES, 2021).
There are also blue areas included in transport infrastructure Right of Way (ROW) areas, composed mainly of retention ponds and drainage. These areas play an increasingly important role in current efforts to adapt to climate change, improving the resilience of transport infrastructure (CEDR, 2016; UIC, 2023). Their distribution within the landscape, along with the aquatic vegetation or the presence of pollutants will dictate whether they become either important areas for biodiversity or ecological traps (Langton et al., 2001; Hassall & Anderson, 2015; Clevenot et al., 2018).
In general, these habitats can have an important role in improving the ecological conditions of the landscapes where infrastructure are embedded. The characteristics of these surrounding landscapes should be considered and evaluated to decide the most appropriate management of these ecosystems, so they provide the best possible benefits for each particular ecological context.
Green and blue areas: planning appropriate management
Transport Infrastructure includes green and blue areas within their Rights of Way (ROW) managed by transport authorities and stakeholders which operate the infrastructure. These areas are also named Habitat-related to Transport Infrastructure (HTI).
- Green areas correspond to terrestrial habitats such as verges adjacent to linear transport infrastructure, wildlife passages, resting areas, surfaces under powerlines or airfields.
- Blue areas correspond to aquatic habitats such as water retention ponds, ditches and other elements associated with drainage systems.
While the primary functions of HTI are to guarantee infrastructure safety and resilience, these areas must also contribute to the prevention of biodiversity loss. Ecological engineering may help to restore soil and vegetation and establish infrastructure related ecosystems which can be developed in green and blue areas. Nature-based Solutions (NbS) may be applied instead of traditional solutions based on artificial materials and practices. These techniques could contribute to reducing pollution, preventing landslides, adaptation to climate change and be of benefit to both biodiversity and people.
Appropriate HTI design and management is critical to the mitigation of disturbance of adjacent habitats, avoidance of IAS spread, forest fire propagation and reduction of other negative impacts of infrastructure on biodiversity. HTI may also be a valuable element in ‘green infrastructure’ e.g., contributing to the restoration of ecological connectivity or providing wildlife refuges. However, special attention is required to avoid the creation of ecological traps or increasing the negative impacts on landscapes adjacent to the infrastructure.
In the framework of European decarbonisation goals, some areas associated with infrastructure are being re-designed to play a role in carbon sequestration or energy production through biofuel, photovoltaic panels etc. These actions are not confined to areas associated with road and railway, but also at airports, under powerlines and other HTI. Since this use may compete with alternative management strategies to promote biodiversity around infrastructure, an appropriate planning and environmental assessment must be undertaken to guarantee that No Net Loss (NNL) to biodiversity is caused.
Landscape perspective is crucial when designing HTI management options. Multicriteria analyses should be conducted, including parameters of infrastructure safety, biodiversity enhancement, ecosystem services provision and climate mitigation to identify management options which provide the best possible benefits to biodiversity and people. Alternatives which could be positive in an urban or cropland-dominated landscape may cause negative effects in a natural protected area. Species planted restore vegetation must also be chosen according to the composition of the ecosystems in the surroundings.
Many actions described in this section could be developed by improving maintenance practices or by modifying elements of the infrastructure during its operation (see Chapter 7 – Maintenance). Transport authorities and companies operating transport infrastructure are key stakeholders in undertaking such actions which can reduce biodiversity loss and even achieve a biodiversity ‘Net Gain’ (NG) (see Chapter 3 – The mitigation hierarchy). Actions must be developed in coordination with environmental authorities and local stakeholders as the landscape context is crucial.