The side effects of the cure: Large-scale risks of a phytosanitary action plan on protected habitats and species

Abstract

Agriculture acts as a predominant factor that affects the state and functionality of ecosystems worldwide. Nevertheless, in case of emergency actions for counteracting the expansion of plant diseases, large-scale and harmful agricultural practices can be legally allowed without considering their environmental impact. Here, we assess the risks to the conservation of protected habitats and species arising from the implementation of an emergency action plan for counteracting the expansion of the bacterium Xylella fastidiosa in Puglia, Italy. Based on official cartographic information provided by regional authority, we considered the distribution of habitats and animal species protected by European Directives and orchid species protected by the CITES Convention, and quantified their overlap with the land-cover categories subject to phytosanitary actions at different scales. We used ANOVA to test variations in species susceptibility to proposed agricultural practices. We highlight that the prescribed actions threaten more than 20 % of the regional cover of EU-protected habitats, with expected risk nearing local extinctions for some wetland and grassland habitat types. Both the prescribed mechanical practices and the chemical treatments variously affect the majority of selected animal species. Risks are significantly high to species associated with open habitats and agroecosystems, characterized by a weaker movement ability, or requiring the grass layer for breeding or foraging. Among orchid species, the prescribed actions are particularly threatening to endemic taxa. The risks arising from the implementation of the phytosanitary action plan underline the need to reconsider the currently adopted regulations through a multidisciplinary approach, aimed at integrating biodiversity and ecosystem stability at various scales.

Keywords: Agricultural policy; Environmental impact; Habitats directive; Nature conservation; Risk assessment; Xylella fastidiosa.