Effectiveness of wildlife fences as a tool for controlling cattle fever ticks by mitigating movement of free ranging nilgai

Cattle fever ticks (CFT) caused economic losses to the US livestock market estimated at about $3 billion annually prior to the eradication of CFT from the US. The spread of CFT from the permanent quarantine zone in south Texas is a persistent threat with political and economic ramifications. Nilgai antelope are co-evolved hosts of cattle fever ticks in part of their native range. Following separate introduction events, both species now coexist in portions of northern Mexico and southern Texas. Nilgai have large home ranges and can act as transport hosts of cattle fever ticks, potentially carrying them beyond the permanent quarantine zone, one tool being employed to limit the movement of large ungulates such as nilgai is the installation and upkeep of game fencing in wildlife corridors. We aim to demonstrate the effectiveness of game fencing as a barrier to wildlife and CFT movement in the permanent quarantine zone of south Texas. Nilgai from two populations in a National Wildlife Refuge system were captured and fitted with GPS radio collars and tracked over a 1.5-year period. Our initial findings indicate that continuous game fencing is effective at limiting the movement of nilgai. We have detected no instances of population expansions past existing fencing. Preliminary indications are that the successful implementation of continuous game fencing in areas of high nilgai density could effectively restrict ungulate movements. Game fencing, though unconventional, has the potential to serve as an important tool in the eradication of CFT.