Trait-based approach and vulnerability analysis of soil communities affected by pesticide application

The commonly used tools to assess ecotoxicological risk are lacking ecological realism, because they cannot predict the real consequences for natural communities. In recent years, ecotoxicology has moved towards an improved ecological realism developing new tools capable of accounting for the complexity of ecosystems. In particular, the concept of ecosystem vulnerability is now considerd an essential component of site-specific risk assessment. Vulnerability is defined as a function of sensitivity, susceptibility to exposure and recovery potential after a stress. Trait-based assessment is a tool for predicting vulnerability based on the hypothesis that the vulnerability of different species to a stressor can be predicted from their characteristics. Though ecosystem vulnerability and trait-based assessment are two promising concepts and are used in modern ecotoxicology, only few studies are available in the literature, especially on the soil compartment. A field survey was conducted in a vineyard in Northern Italy, under application of pesticides. Microarthropod communities were sampled from the vineyard and from two “control”stations 4 and 10 m outside the plant rows, and identified to the level of taxa (order, sub-order or family level). Morphological, life cycle, physiological and ecological traits were collected for these taxa, to create a big trait matrix. The matrix was intersected with the field survey results to identify which are the traits that cause a major or minor vulnerability to the stress due to pesticide application. The taxa more or less vulnerable were identified according to these traits. In an alternative approach, traits were divided according to the three components of vulnerability. A score was assigned to each trait according to its relation with vulnerability, which was quantified applying these scores and the trait matrix, using an index. Results were compared to those obtained when using the trait based approach. Similarities and differences between the two approaches will be discussed.