Minor rural road networks: values, challenges, and opportunities for biodiversity conservation

Peter G Spooner

doi:10.3897/natureconservation.11.4434

Abstract

Roads corridors are a conspicuous part of most landscapes, which are gaining greater recognition for their role in nature conservation. However roads cause wildlife mortality, alter water and nutrient flows, change local microclimatic conditions, act as vectors for weeds and pest animals, and have other far-reaching effects. Not surprisingly, there is much attention from both road and conservation managers to lessen these impacts, with an emphasis on developing solutions to mitigate the barrier effects of major roads to wildlife movements. However in many anthropogenic landscapes, road corridors can also provide key habitat and connectivity for local biodiversity. In particular, where traffic volumes are low, minor roads often provide critical habitat and refuge for many native species. Knowledge of the ecology and biodiversity conservation values of minor rural road verges has been underpinned by studies in various contexts, such as sunken roads, field margins and hedgerow networks in Europe, to stock routes in Spain and Australia. Despite their different histories and management constructs, important commonalties have been highlighted in terms of their biodiversity values, and the factors which influence these values. As such, minor rural road networks can be vital in providing connected, functioning ecosystems within rural landscapes. The importance of vegetated minor rural road networks will only become more pressing with future climate change. In Australia, road management authorities are tasked with the dual roles of maintaining road transport needs (i.e. priorities for road maintenance and safety concerns), whilst maintaining the environmental values of roads. This paper reviews the biodiversity values of minor rural roads, discusses the challenges and constraints in managing these values, and describes the case of identifying historic roads as an example of enhancing conservation management of these important habitats in rural landscapes.

Highlights

Intensive agriculture has caused irreversible damage to many ecosystems and constitutes a major threat to biodiversity (Sachs et al 2010)
The aim of this paper is to discuss the management of minor roads from an environmental viewpoint, by describing the competing values, management considerations and new opportunities to explore in conserving biodiversity in rural landscapes
The key to success in ensuring the persistence of roadside vegetation is in addressing ongoing human impacts

Summary

Introduction

Intensive agriculture has caused irreversible damage to many ecosystems and constitutes a major threat to biodiversity (Sachs et al 2010). Agricultural-related practices such as land clearing, intensification, inappropriate water-use, and over application of fertilizers have accelerated biodiversity losses worldwide (Conacher and Conacher 1995, Pretty et al 2010) Such human modification and destruction of habitat has transformed once continuous ecosystems into landscapes dominated primarily by mixed pastures and food crops (Lindenmayer and Fischer 2006). Due to changing economies and policies, agricultural (and other human modified) landscapes often experience frequent and extensive land-use changes, the history of which continues to shape present-day landscape patterns and processes (Foster et al 2003, Watson et al 2014) This process results in extensive fragmentation of remaining habitat, creating isolated remnant habitats of varying size and quality (Saunders et al 1991). Road transport corridors can provide vital refuge for species and remnant ecological communities (Bennett 1991, Votsi et al 2012)

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Conclusion