Abandonment terraced hillside and answer of the fire system: some results from Mediterranean old fields

Abstract

The abandonment of agricultural lands promotes temporal changes both in soil characteristics (i.e., increasing organic matter and other quality indicators) and in plant community (i.e., changing its composition and structure, and increasing the fuel load). As a consequence, we can expect differences in the resilience to fire as succession progresses. The aim of this work is to analyse the capacity of an ecosystem to return to pre-fire conditions as a function of the stage of abandonment of old agricultural lands. The study was carried out in the north of Alicante province (E Spain). In long-term abandoned lands, post-fire rainfall modulated plant response, which in turn determined soil crusting, runoff and erosion dynamics. In recently-abandoned lands, the plant community seemed less dependent on rain to recover. Results show a large increase in soil surface crusting in the short term after the fire and it remained high at medium term in long-abandoned lands colonised by pine forest. Fire scarcely modified runoff and erosion in recently-abandoned lands whereas in forest lands the post-fire values increased by some orders of magnitude and remained highly dependent on rain characteristics in the short and medium term after the fire. The results obtained show evidences of increased vulnerability to fire in long-abandoned lands colonised by pine forests