Wild boar are making a comeback throughout Europe. This sounds like good news, but not everyone is happy. Denmark, concerned about disease threatening their pork industry, is constructing boar-proof fencing along almost their entire border with Germany to keep the wild pigs out. The Danish fence is highly controversial. Some fear the ecological impacts, while others fear the hostile image a fence presents. But there’s a deeper question: is the fence even necessary?
Interestingly, this very question was already considered back in 2006 by Néstor Fernández, Stephanie Kramer-Schadt, and Hans-Hermann Thulke. Writing in Ecology and Society, Fernández et al. considered how wild boar might be reintroduced successfully to Denmark without causing too much damage to pig farming. Their approach included a spatial analysis of Denmark, pointing out the most suitable boar habitat, where a small number of introduced individuals could multiply. They also highlighted areas where boars might risk contact with pig farms. Fortunately for the boars, while there are many pig farms, they are concentrated in certain areas. Fernández et al. identified several areas, mostly in the Jutland peninsula, where wild boar could be reintroduced to Denmark with suitable habitat and acceptable risk to pigs.
Even so, action would be required to manage boar populations while preventing disease exchange with domestic pigs. According to Hannes Geisser and Heinz-Ulrich Reyer in Journal of Wildlife Management, managing boar damage is easier said than done. (They’re focused on crop damage rather than preventing spread of disease, but many of the same issues still apply.) The two main methods for protecting crops, and presumably pig farms, from wild boar are fencing and culling of boar populations. Fencing, as it turns out, is usually not effective.
What is effective, according to Geiser and Reyer, is hunting. But hunting is time-consuming, and even successful hunts have limited results given the high fecundity of the average wild boar sow. In some places, fences combined with hunting are successful. In general, though, Geiser and Reyer advocate for greater hunting effort, in addition to researching different harvest models and hunting techniques.
It is clear, unfortunately, that the reintroduction of wild boar will inevitably cause some damage to pig farming. It is also clear that the wild boar population will require heavy management and in most areas will never truly be wild. Even in the unlikely event that the fence works as advertised, the fence alone will probably not be sufficient to protect the pork industry or prevent culling of boar. According to Fernández et al., local residents are more likely to support boar reintroduction when the risks and benefits are properly explained. Approaching the boar issue as a manageable risk may ultimately be more effective than attempting to completely eliminate any risk.