Soil and vegetation dynamics in a chronosequence of abandoned vineyards

Euro-Mediterranean countries have undergone radical changes in their traditional landscapes due to the abandonment of rural areas. Natural vegetation rapidly colonizes abandoned lands and cause changes in ecosystem functioning. Our main objective was to study how time since abandonment of vineyards influences the physical, chemical and biological properties of the soil and the vegetation composition and cover. In 2016, we selected a chronosequence of six abandoned vineyards (1, 3, 7, 11, 25 and 40 years), an active vineyard, and a plot of land that has not been used as a vineyard for at least the last 60 years. Soil physical-chemical variables, including the organic matter fractions and available nutrients, were analysed. To observe the variation in the biochemical properties of the soils, the activities of 11 enzymes were determined, relating to the main macronutrient cycles: carbon (C), nitrogen (N), phosphorous (P) and sulphur (S) cycling. Three sites (1 m(2)) were randomly established on each plot within the area occupied by annual grasslands, and species cover was estimated in order to obtain the species density and cover of plant functional traits. Our results showed that the abandonment caused major changes in the functioning of the ecosystems. Secondary succession in abandoned vineyards was characterized by a significant increase in plant species density and by changes in the composition of the annual grasslands, from an early brassicaceous community to a late cistaceous community. This was accompanied by an increase in soil TOC (0.38-1.78%) and TN (0.14 to 0.26 %) content, and the activity of most enzymes. These changes occurred more rapidly during the first two decades after abadonment.