Intensive monitoring suggests population oscillations and migration in wild boar Sus scrofa in the Pyrenees

M Sarasa,J.-A Sarasa

doi:10.32800/abc.2013.36.0079

Abstract

As few studies have analysed local variability in populations of wild boar Sus scrofa in Western Europe in recent years, our understanding of ecological processes currently affecting this species is limited. To analyse questions regarding local variability in wild boar abundance, we used information from 442 traditional drive hunts monitored throughout eight hunting periods in the Pyrenees mountain range (Urdués, N Spain). Results showed temporal oscillations in abundance, and a non–linear decrease of 23% in the number of wild boar seen per drive hunt between 2004 and 2011. Numbers of dogs and hunters per drive hunt also affected indexes of wild boar abundance. Inter–annual variations in bag size may cause overestimations of variations in boar abundance and may even deviate from the population dynamics inferred from the number of wild boars seen per drive hunt. The multimodal patterns of wild boar abundance during the hunting periods suggest migrations in the Pyrenees. Our findings highlight the limitations of hunting bag statistics in wild boar. Further studies are required to guarantee information–based sustainable management of wild boar populations.

Highlights

Over the last 30 years, most studies discussing or men tioning wild boar Sus scrofa abundance and densities in Western Europe have suggested that overall wild boar populations are increasing (Sáez–Royuela & Tellería, 1986; Melis et al, 2006; Marco et al, 2011)
For the number of wild boars seen per drive hunt, the fitted model sug gests an increase of 13% between 2004 and 2005, a decrease of 44% between 2005 and 2009, and an in crease of 20% between 2009 and 2011
Between 2004 and 2011, this model suggests an overall reduction of 23% in the number of wild boars seen per drive hunt

Summary

Introduction

Over the last 30 years, most studies discussing or men tioning wild boar Sus scrofa abundance and densities in Western Europe have suggested that overall wild boar populations are increasing (Sáez–Royuela & Tellería, 1986; Melis et al, 2006; Marco et al, 2011). It has been suggested that wild boar might reduce the availability of summer grazing areas through soil disturbance (Bueno et al, 2010), such issues have raised considerable controversy (Risch et al, 2010; Wirthner et al, 2011; Wirthner et al, 2012). In light of these concerns and of the predicted increase in wild boar populations as a response to global warming (Melis et al, 2006), mana gement tools to control and reduce wild boar populations are of much interest (Massei et al, 2011). Very few studies have addressed whether these increases are the result of a source–sink gradient, sustained by woodland environments with increasing numbers of wild boars, or whether wild boars are locally adapt ing to agricultural and urban environments in which effective and perceived hunting pressure is low and opportunist foraging is facilitated by city dwellers (Cahill & Llimona, 2004)

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Results

Conclusion