Interannual climate variability determines the efficiency of functional recovery in dry Mediterranean abandoned vineyards

Abstract

European abandoned lands have been increasing in recent decades, and this is occurring in a climate change scenario in which the consequences of their interactions are still little known. We tested the hypothesis that the functionality of abandoned lands responds differently to year‐to‐year climate variations depending on the time since the cessation of agricultural activity. We constructed a chronosequence in Mediterranean abandoned vineyards at six different years of abandonment in 2016 (1, 3, 7, 11, 25, 40), in a current vineyard and in land not dedicated to vineyards. Soil total organic carbon (TOC), total nitrogen (TN) and available nutrients, enzyme activities relating to the main macronutrient cycles and plant‐community attributes were studied at 24 sites over three consecutive years. A total of 144 samplings were performed. TOC, TN, most enzyme activities and plant species density increased throughout the chronosequence, although interannual climate variability also had a significant influence. The extreme drought event increased the activity of enzymes related to the carbon (C) and nitrogen (N) cycle, as well as the stock of TOC after a subsequent decrease in TOC when environmental conditions became favourable. In contrast, plant species density and the cover of certain plant functional traits such as mycorrhizal symbiotic plants (Cistaceae) and N‐fixers (Fabaceae) decreased significantly. Our results also demonstrated that extreme drought events had a higher negative impact on lands that had been abandoned for longer. We therefore conclude that extreme drought events damage the functionality of Mediterranean abandoned agrosystems, thus affecting all its compartments and jeopardising its functionality.