Systemic roadside vegetation strategies: How moss and native flora mitigate flooding, air pollution, and biodiversity loss in European motorway corridors

Indigenous land management practices, such as those in the Andes and East Asia, demonstrate how moss and native flora are integrated into holistic water and soil systems, rather than isolated 'solutions' to infrastructure problems. These systems prioritize biodiversity and resilience, contrasting with Europe's industrialized roadside vegetation that often relies on monocultures. The displacement of such practices by colonial and industrial land use has contributed to the very problems the moss narrative seeks to address.

The motorway networks in Europe were built during the 20th century, a period that saw the systematic replacement of diverse, water-retentive landscapes with impermeable surfaces and soil-depleting monocultures. This shift coincided with the rise of industrial agriculture, which prioritized yield over ecological function, leaving roadside ecosystems ill-equipped to handle heavy rainfall. Historical precedents, such as the Dutch *polder* system, show how traditional water management techniques could inform modern infrastructure design.

Cross-culturally, moss is often seen as a symbol of ecological balance and adaptability, with its use in traditional medicine (e.g., in Traditional Chinese Medicine) and ecological restoration (e.g., in Japanese *satoyama* landscapes) highlighting its multifunctional role. In contrast, Europe's roadside vegetation strategies are often technocratic and monocultural, lacking the adaptive capacity of these systems. The integration of moss into motorway corridors could draw from these traditions to create more resilient landscapes.

Scientific evidence supports the role of moss and native flora in mitigating flooding by increasing soil infiltration rates and reducing runoff, while also capturing particulate matter and absorbing pollutants like nitrogen oxides. Studies in urban green infrastructure show that moss-dominated systems can reduce air pollution by up to 30% in high-traffic areas. However, the effectiveness of these systems depends on soil health, which is often compromised by industrial agriculture and motorway construction.

Artistically, moss has been a symbol of quiet resilience and interconnectedness, appearing in Japanese *wabi-sabi* aesthetics and Celtic folklore as a marker of ancient, enduring landscapes. Spiritually, it represents the balance between growth and decay, a metaphor for the regenerative potential of roadside ecosystems. Incorporating moss into motorway design could foster a deeper cultural appreciation for ecological processes, shifting public perception from 'tidy landscapes' to living systems.

Future modelling suggests that integrating moss and native flora into motorway corridors could reduce flood risks by up to 40% in high-rainfall regions, while also lowering air pollution and supporting biodiversity. Scenario planning indicates that such systems would require cross-border cooperation in the EU to standardize green infrastructure policies and funding. Additionally, climate projections show that moss-based systems may become more effective as temperatures rise, due to their adaptability to changing hydrological conditions.

Marginalized voices, such as rural farmers and indigenous communities, are often excluded from discussions on roadside vegetation, despite bearing the brunt of flood damage and soil degradation. Small-scale farmers in Europe, particularly in Eastern and Southern regions, have long advocated for agroecological practices that could inform roadside vegetation strategies. Their knowledge of local ecosystems and water cycles is critical to designing resilient infrastructure, yet it is sidelined in favor of technocratic solutions.