The influence of land-use history on roadside conservation values in an Australian agricultural landscape

We investigated the influence of land-use history on roadside conservation values in a typical agricultural landscape of southern New South Wales (NSW), Australia. Historical information on the development of rural road reserves was collated from recently digitised 19th and 20th century pastoral and parish maps, such as road-reserve age and original survey width, as well as data relating to locations of old fence lines, county or parish boundaries, previous reserves, stock routes and road re-alignments. Ordinal regression statistics showed that road-reserve age and road width were significant predictors of roadside conservation values. Importantly, analyses showed that the first roads surveyed during the pastoral era (1840-1860s) were often of lower conservation value than roads surveyed in the 1870s, when major clearing of these landscapes commenced. Most roads were surveyed at one-chain width (20.12 m); however, pre-1870s historic roads, traveling stock routes (TSRs) and county or parish boundaries were significantly wider, decisions that have indirectly led to higher present-day conservation values. In separate analyses, historical data also formed a useful model to predict the absence of short-lived shrub species. These results highlight the influence and prevailing imprint of historical land-use on current roadside conservation values.