Assessment of wild boar rooting on ecological and pastoral values of alpine pyrenean grasslands

C G Bueno,I C Barrio,D Gómez-García,C L Alados,R García-González

doi:10.3989/pirineos.2011.166003

Abstract

Wild boar rooting is nowadays one of the main disturbances in Pyrenean alpine grasslands. Its consequences for the ecosystem are not perfectly understood yet despite alpine grasslands in the Pyrenees have an important economic role and a priority conservation interest. The ecosystem services of this habitat lay mainly on pastoral and ecological values that wild boar rooting seems to affect. In this study, we measured those ecological and pastoral values at different scales to improve our understanding of the reach of these disturbances in this sensitive ecosystem. At landscape and community scales we compare disturbed and undisturbed areas in pastoral, ecological and community maps of the study area by means of a geographic information system. At a local scale we compare ecological and pastoral values of different plant groups (based on species abundance), within and outside wild boar rootings. A preference for areas of high pastoral and intermediate ecological values was found for wild boar rooting at the landscape level. However at the community level, disturbances notably reduced pastoral and ecological values in all communities. At the local level, the ecological value of bulbs and the pastoral value of annual dicots increased within disturbances, suggesting that disturbances may favour functional group diversity. In sum, wild boar rooting affects Pyrenean alpine grasslands moderately, with higher affection to pastoral than ecological values at all levels, what should be considered for the management and preservation of these habitats since these disturbances are likely to increase.

Highlights

A crucial step to value an ecosystem is to accurately report how it may contribute to human wellbeing, through measuring what have been called ‘ecosystem services’
Areas with high pastoral values were actively selected by wild boar to root while low and intermediate values were significantly avoided (Figure 2b)
The multi-scale approach used in the present study has let us assess the effects of wild boar rooting on ecological and pastoral values of Pyrenean alpine grasslands

Summary

Introduction

A crucial step to value an ecosystem is to accurately report how it may contribute to human wellbeing, through measuring what have been called ‘ecosystem services’. The greatest historical environmental change in these areas has been the spread of grasslands through scrubland and forest reduction from the Middle Ages on (Fillat et al, 2008) This progressive change due to livestock activities has developed a seminatural system with high ecological and pastoral values in a dynamic trade-off based on plant-herbivore interactions (Olff & Ritchie, 1998; Austrheim & Eriksson, 2001; Fillat et al, 2008). Livestock grazers have changed in European mountain systems from almost exclusive sheep herds to comparatively higher numbers of cattle heads (Macdonald et al, 2000; Lasanta-Martínez et al, 2005) Alongside with this trend, a sharp decline of extensive husbandry has occurred in the last decades in favour of more productive intensive farming systems (Luick, 1998; Körner, 1999). This last trend has been related with drastic changes in the ecosystem structure, such as shrub encroachment and forest recolonization (Lasanta-Martínez et al, 2005; Lasanta-Martínez et al, 2006), what in turn may increase fire events (Carcaillet et al, 2009), reduce biodiversity (Helm et al, 2006), and boost some forest animal populations beyond an equilibrium threshold (Laiolo et al, 2004)

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Conclusion