Anàlisi de l’impacte de la gestió forestal postincendi sobre la comunitat d’insectes

Abstract

The popularization of the use of wood from burned forest by salvage logging is due to the growing demand for biofuel and the perception of burned habitats as areas with poor ecological value, among others. This massive extraction of biomass is associated with some impacts on the ecosystem, which affect both the biotic and abiotic parts. Ground-dwelling insects play an essential role in the ecosystem processes and have a high sensitivity to environmental changes, which makes them excellent bioindicators. This bioindicator capacity is used to study the impacts of postfire management carried out in the Vilar area, located in the municipality of Blanes. The differences in the number, biomass and length of insects captured with pitfall traps in May 2018 are evaluated between replicated plots of 3 forest treatments. These consist of Salvage logging, Sustainable logging (According to recommendations of the Manual of Good Practices of Anifog Project), and areas without Intervention. In addition, it is taken into account the presence of different microhabitats in each treatment: Bare ground, Outbreak areas of Laurustinus (Viburnum tinus) or Strawberry tree (Arbutus unedo) and Piles of wood debris. The results obtained indicate that the combinations of Outbreak in Salvage logging and Sustainable logging show higher mean values of insect abundance and biomass, whereas the body length is higher in Bare ground of Sustainable logging. The differences that present the values of abundance were described as significant. The influence of the variable order on the body length led to study the variable in two different taxa widely used as bioindicators, ants and coleopteran. The GLMs performed for these two orders do not show significant differences in the corporal length according to the applied forest management. To finish the analysis, PCAs were made with abundance and biomass data, to know the tendencies of each order in the different treatment and microhabitat combinations. It emphasizes the importance of springtails and beetles in the salvage logged areas, the Homoptera order associated with the sprouts and Diptera and Embioptera in the piles of wood debris. Finally, it is concluded that there will always be taxa benefited and others harmed by the different forest management alternatives, and that it is necessary to continue the study of the community of insects with more follow-up years