Functional biodiversity and farming techniques: how to measure impacts?

Abstract

Farming and environment are key issues on political and social agendas on a global scale. In the past two decades, agricultural systems went through a major revision having in mind ecological and landscape concepts on a conservation basis. Technical profiles (TP) are used as study tools to evaluate operational costs and to assess the deviation between theoretical production models and each farm system. TPs of sustainable crop systems such as integrated production and organic farming are based on principles, tasks and technologies, such as crop protection, cover crops and ecological infrastructures preservation, that expectably induce differences in the functional biodiversity present in each system. The main target of the present work was to develop a methodology to measure the impact(s) of farming practices on pest importance (occurrence and damages) and functional biodiversity. This study was carried out during 2005 and 2006 and was supported by the national project AGRO 545 “The environmental indicators to assess the IPM, the integration production, the organic farming and the sustainable use of pesticides ”. A survey was performed with 191 vineyard farmers in the four Portuguese main important regions: Verdes, Douro, Dão and Alentejo. The survey was carried out during the crop season and biodiversity was assessed (pests and beneficial arthropods) simultaneously. The results presented here are related to a preliminary data analysis. As expected, IPM and organic farming impact on the environment tends to be low, but conventional systems revealed a similar tendency, induced by the need of reducing production costs. Differences among regions were also found, as expected, due to territorial structure and farm dimensions. In monitored vineyards, 48.2% of species variance was explained by the studied variables. The number of discontinuities in the surroundings was found to be associated to all arthropod functional groups.