Temporal evolution of litterfall and potential bio-element return in a successional forest sequence of the Espinal Ecoregion, Argentina

Abstract

Aim of study: The aim of this work was to assess the litterfall contribution and the return of bioelements of a successional forest sequence from the Mesopotamian Espinal (Argentina) which was associated with livestock production. Area of study: Mesopotamian Espinal, Argentina. Material and methods: Litterfall samples were taken and a chemical characterization of their fractions was determined in three stages: a) in the initial successional stage (IF); b) in an intermediate secondary forest (SF); and c) in a mature forest (MF). Main results: The litterfall contribution of the three forests was 1140 ±98, 2947 ±154, and 2911 ±57 kg DM ha-1 yr-1; respectively. The IF showed a seasonal pattern of contribution with a peak occurring during summer (528 ±85 kg DM ha-1 yr-1), then decreasing during autumn, winter, and spring (241 ±30, 165 ±27, and 207 ±29 kg DM ha-1 season-1,respectively). The SF showed a rather constant seasonal pattern (about 750 kg DM season-1). The MF showed significant differences among seasons, the maximum and minimum contributions ranging between 846 ±29 and 598 ±33 kg DM ha-1 season-1 in summer and spring, respectively. The litterfall leaves/branch ratio decreased as ecological succession advanced, being lower as the forest gets more mature. As a consequence, this ratio can be used as an indicator of maturity in the sequence. The potential return of bio-elements of the successional forest sequence was proportional to the litterfall input, with a maximum amount of N in the Fabaceae species. Research highlights: The litterfall assessment and the leaves/branch ratio allowed the characterization of the successional stages in Xerophytic forest used for livestock production.