Re-imagining Urban Infrastructure for Biodiversity: Can Railway and Utility Easements Enhance Ecological Connectivity in Cities?

Hugh Robertson Stanford , Holly Louise Kirk 

Urban biodiversity is increasingly recognised as essential for ecological and social outcomes in cities. At the same time, urban densification is reducing the land available for biodiversity interventions, creating a need to make better use of existing spaces. This study examines the existing and potential value of railway and utility easements in contributing to habitat connectivity for a range of species in urban settings.

In this study, we assess landscape connectivity across Greater Melbourne, Australia, for three species groups with differing traits and habitat requirements: woodland birds, pollinator insects, and reptiles. We conduct a series of habitat planting simulations to evaluate both the current and potential contributions of railway and utility easements to ecological connectivity. We then use linear mixed models to examine how planting intensity, easement type, and local landscape characteristics influence changes in connectivity resulting from these planting interventions.

Results show that railway and utility easements already make substantial contributions to ecological connectivity, with strong potential for further enhancement through strategic planting initiatives. Simulations indicate that meaningful gains in connectivity can be achieved across all species groups studied. However, we identify a diminishing returns effect, whereby the connectivity gain per unit of habitat decreases as the proportion of an easement planted increases. Outcomes are also strongly shaped by local landscape context, and vary considerably between species. These findings highlight the value of urban greening initiatives on railway and utility easements, while emphasising the need for targeted, context-sensitive planting strategies to maximise ecological benefits.