The use of exclusion fencing as part of wildlife conservation programs has been increasing in recent years, particularly in Australia. Soil corrosion damage sustained on fences is a significant management concern as the weakened fence netting can provide opportunities for feral animal incursions into fenced safe havens. Soil corrosivity risk mapping can assist with the design of fenced nature reserves to reduce the frequency of fence repair and replacement. However, very little research has focused on developing methods for accurately predicting fence corrosion rates in different surface soil environments. This paper assesses the use of different soil attributes as corrosivity indicators for identifying areas of low, moderate and high fence corrosion risk in different soil environments present in South Australia (20 field sites). Zinc corrosion rates measured on zinc-aluminium fence samples (buried at sites for 9 months) ranged by a factor of nearly 50, with low rates of fence corrosion (0.1-0.7 mu m/year) observed at five sites, medium rates (0.7-2.1 mu m/year) observed at 10 sites, and extreme rates (>8.4 mu m/year) observed at four sites. Fence corrosion risk was predicted using soil pH, soil salinity and texture data, and a soil corrosivity risk index developed for use in arid soils in South Australia. Predicted zinc corrosion rates matched field observations at 45 % of field sites. The highest rates of zinc corrosion (>4.2 mu m/year) were observed at field sites with highly alkaline (pH > 8.5) and highly saline (ECe >= 5 dS/m) soils. An improved fence corrosion risk classification method, referred as the Fence Corrosion Risk Decision Tree was developed using these soil pH and salinity thresholds, which correctly predicted fence corrosion risk at 67 % of field sites at Olympic Dam and Farina and 50 % of field sites on the Yorke Peninsula. Further research is needed to assess the ability of this method to predict long-term fence damage (>2 years exposed to soil conditions).

Soil corrosivity is a term used to describe the corroding susceptibility (risk) of metal infrastructure in different soil environments. Soil corrosivity mapping is a crucial step in identifying potentially problematic, high-maintenance fence lines and can help improve fence longevity by identifying soil environments where the use of more expensive, corrosion-resistant materials would be more cost-effective in the long term. Soil corrosion damage sustained on exclusion fences can be a serious management issue for conservation programs and initiatives, as it weakens the fence netting and provides opportunities for invasive animal migration and occupation (e.g. feral cats and foxes) into areas of high conservation value. The increasing accessibility of geospatial analysis software and the availability of open-source soil data provide land managers with the opportunity to implement digital soil databases and pedotransfer functions to produce fence corrosion risk maps using commonly measured soil attributes. This paper uses open-source government agency soil data (shapefiles) to map fence corrosion risk in the southern part of the Yorke Peninsula in South Australia, with the intention to assist with the installation of a new barrier (exclusion) fence as part of the Marna Banggara rewilding project. The risk classifications (low, moderate and high risk) made by this map were compared with rates of zinc corrosion (mu m/year zinc loss) observed at field sites and correctly predicted the amount of fence damage sustained at five of the eight sites. The mapping approach outlined in this study can be implemented by environmental managers in other areas to inform strategies for enhancing fence longevity.