Wildlife Agriculture Interactions, Spatial Analysis and Trade-Off Between Environmental Sustainability and Risk of Economic Damage
Mario Cozzi, Severino Romano, Mauro Viccaro, Carmelina Prete, and Giovanni Persiani
Abstract Over the last few years, wildlife damages to the agricultural sector have shown an increasing trend at the global scale. Fragile rural areas are more likely to suffer because marginal lands, which have little potential for profit, are being increasingly abandoned. Moreover, public administrations have difficulties to meet the growing requests for crop damage compensations. There is therefore a need to identify appropriate measures to control this growing trend. The specific aim of this research is to understand this phenomenon and define specific and effective action tools. In particular, the proposed research involves different steps that start from the historic analysis of damages and result in the mapping of risk levels using different tests (ANOVA, PCA and spatial correlation) and spatial models (MCE-OWA). The subsequent possibility to cluster risk results ensures greater effectiveness of public actions. The results obtained and the statistical consistency of applied parameters ensure the strength of the analysis and of costeffectiveness parameters.
Dealing with problems related to the damages caused by wildlife to the agricultural sector involves environmental and socioeconomic sustainability issues associated with the management of natural resources.
If, on one hand, farmers are suffering due to the damages caused to crops, on the other, hunters push towards the growth of wild fauna populations for having greater hunting opportunities. This has led to conflicting interests in many European (Wenum et al. 2003; Calenge et al. 2004; Geisser and Reyer 2004; Herrero et al. 2008; Thurfjell et al. 2009) and Italian areas (Brangi and Meriggi 2003; Amici et al. 2012; Serrani 2012).
Under the current agricultural-forestry conditions, the pressure exerted on agricultural crops by wild animal populations, in particular ungulates, is a major problem for the development of rural policies, as it creates a conflict between wild animals and farmers, resulting in growing costs for public administration to compensate for damages.
From an economic point of view, the damages caused to crops, especially by ungulates, are dramatically and seriously growing. Unluckily, the national bibliography does not report recent data of this phenomenon. The unique national data date back to 2004 when, according to the estimates provided by the Ungulate National Database (Carnevali et al. 2009), the total indemnified compensations amounted to about 8.9 % for damages caused by ungulates. When analysing the impact of each single species, it results that, at the national level, 90 % of damages are attributable to the wild boar (Sus scrofa L.).
In Basilicata region, the observed trends in relation to the economic size of damages confirm the above data. As a matter of fact, in the 6-year period from 2007 to 2012, the damaged area doubled, shifting from about 2,800 to 5,850 ha; as a result of this increase, the estimated compensations have more than doubled, shifting from over 550,000 € till 1,134 M€. The same proportion does not unluckily apply to the compensations actually paid to private citizens that shifted from 64.7 to
39.5 % of estimated compensations. At the regional level as well, there is a high incidence of wild boar that is the major damaging species, with 98 % of damages caused to crops.
The conflict of interest associated with the presence of the wild boar on land, together with some objective technical difficulties (related to the quantitative estimate of populations), makes the management of this species particularly critical. Special attention is to be attached to the areas in which the use of land for agriculture or animal production is particularly important, with a great impact on crops.
As for the possible actions to undertake in order to control the expansion of wild animal populations, the literature confirms that hunting is not actually a solution. In fact, it has been found that the populations subject to strong hunting pressure increase their prolificacy (Herrero et al. 2008; Servanty et al. 2009) by bringing forward the sexual maturity of females and by increasing to two deliveries per year. Some authors (Massei and Toso 1993; Boitani et al. 1995) state that wild boar is a very adaptable species following the “r-selection” strategy (many offspring and relatively low parental care). Due to this kind of reproduction, the expansion of European wild boar populations cannot be controlled using the traditional hunting methods.
This is true for traditional hunting but not for the selective culling of the species. In fact, population control strategies can involve both selective hunting techniques (shooting from fixed positions, using dog teams that chase wild boars towards hunters (cerca technique), or the so-called girata, where a single bloodhound is used as “finder”) applied by appropriately trained operators and “in vivo” catches, through self-opening fences (closed fencing), where animals are attracted by a feed bait. Closed fences are highly selective within the social groups of the population and are used to catch mostly the population of red, striped and adult females (in a decreasing order), whereas males are caught much less frequently. The selective action of traps is matching with the objective of the control, since immature and female boars are the target social groups to control the population dynamics (Toso and Pedrotti 2001).
Positive effects in the reduction of damage to agriculture have also been obtained by permanent and mobile electric fences. For the latter type, different analyses carried out in France by the ONC (Office National de la Chasse, National Hunting Service) in the 1977–1980 period have shown the technical and economic effectiveness of this practice as an active protection of crops from wild boar-caused damages, provided that some rules for installation and monitoring are complied with.
Electric fencing may be basically installed by two operational procedures: (a) as a specific protection along the boundary of the individual holding and (b) as a linear protection in boundary areas between large woodlands and typical farmlands, for separating cultivated from natural lands. If the first type might be a good solution for private landowners, the second could be particularly suitable for public administrations with an eye to long-term planning.
Among the methods reported in the literature, chemical and noise disturbances have shown significant failure, and this is due to the fact that the species adapts rapidly to these disturbances. The research is designed to (a) set up a historical geo-referenced database of the damages caused by wild animals in the area under study and (b) identify the areas at high risk of damage, on which to focus the attention and the appropriate actions.
-  This amount accounts for 85.56 % of the ascertained damage. It results that the overall amount ascertained for damages caused by ungulates in 2004 would not be less than about 10.3 %