


Publications
Kirstin Long and Alan Robley
Arthur Rylah Institute for Environmental Research
Department of the Environment and Heritage, 2004
ISBN 0 642 54992 3
While most fences are regularly monitored for signs of damage or feral animal breaches, the enclosed area is less frequently systematically monitored for feral animals (see Table 2). The need for systematic monitoring will vary between sites. Feral animal incursions are likely to be opportunistically detected by vigilant staff (through the identification of scats, tracks or killed prey), at sites that are intensively managed. However, incursions are much less likely to be detected at large sites and at sites that are traversed irregularly by staff. Systematic monitoring is recommended in the latter case, and in the former case if a more accurate assessment of management actions and of the effectiveness of the fence over time is required. Systematic monitoring most frequently takes the form of standardised spotlighting transects, sand plots or track transects (animal prints are monitored in the latter two methods).
To prevent delays in finding and destroying feral animals detected within the enclosed area, a response plan is recommended. The required level of response will vary according to the level of threat the feral species pose to the protected conservation value. For example, the surplus killing behaviour of foxes and dingoes means that a single incursion into an enclosure may spell the demise of a considerable number of threatened native animals (Short et al. 2002), particularly if the feral animal is not rapidly detected.
If feral animals are detected within the enclosure it may be useful to determine if these animals are regularly crossing the fence or are resident within the enclosure (possibly having been fenced-in and gone undetected). At the Royal Botanic Gardens Cranbourne, fox baits containing the biomarker Rhodamine B were laid outside a recently constructed fence, and transects were regularly walked within the reserve to search for fox scats containing the marker, which would indicate fence breaches (Coates and Wright in press). Similar methods may be used elsewhere.
Systematic monitoring will provide a good indication of the fence's effectiveness under local conditions but this effectiveness will not necessarily translate to similar fence designs in other environments. If monitoring of feral animal activity is also conducted outside the fence the effectiveness of the fence under different levels of feral animal pressure can be quantified as feral animal densities fluctuate over time (either naturally or as a result of control operations).