Wild boar abundance and hunting effectiveness in Atlantic Spain: environmental contraints

Wild boar populations have increased over the species’ entire Spanish range even in areas with no direct influence of humans (like artificial feeding, watering, etc.). Some detrimental effects were raised in relation with the wild boar increase, which justifies the development and improvement of methods to estimate wild boar abundance and population trends. Harvesting information is important for planning the extraction policy and managements goals, mainly for elusive species as wild boar. Nevertheless this information could be biased by several factors, being hunting effectiveness one of them. Thus, our objective was to investigate how landscape structure affects wild boar abundance and hunting effectiveness. Based on data of 44 game territories for 4 seasons (from 1998-1999 to 2001-2002), we quantified hunting effectiveness as the proportion of animals caught in relation to the total seen by hunters. Then, we estimated a corrected wild boar abundance index following the De Lury’ method. Twenty two factors related with landscape structure, topography, human infrastructures, and hunting pressure, were considered to study their effects on wild boar abundance and hunting effectiveness by means of General Linear Models (GLM). Landscape structure factors that possibly resembled increased visibility (abundance of fern and landscape diversity index) and availability of wild boar resting places (percentage with south-west orientation) statistically associated with effectiveness. Factors related food availability (abundance of pre-forest but also landscape diversity index) statistically and positively associated with wild boar abundance. We suggest that corrected wild boar abundances should be considered in monitoring schemes to obtain more suitable wild boar abundance estimates. The applicability of hunting effectiveness data in catch-effort methodologies is discussed.