The ecological role of Pyrus Spinosa Forssk. in the ecosystem recovery and land restoration of Mediterranean woodlands

Abstract

In the Mediterranean basin, large areas still call for active reforestation, having a very low woody cover, thus resulting less resistant and resilient to climate change and suffering from a higher risk of soil degradation processes. Knowing the effects on soil fertility and carbon sequestration of single woody species can be of great practical importance, although being rarely tested. We aimed to assess the effect of Pyrus spinosa on soil fertility (soil carbon and nitrogen), microbial biomass and carbon sequestration (in aboveground stems) of Mediterranean pasturelands. The research was carried out in Ficuzza Nature Reserve (NW Sicily), where large areas are composed of extensive pasturelands mixed with mantle vegetation dominated by shrub species of the Rosaceae family. We assessed the effect of pear individuals considering a paired-site approach and comparing each individual with nearby grassland vegetation patches. Particularly, we measured plant height, basal diameter and crown projections along with cardinal directions. We also compared pear individuals with a single trunk and stumps with coppice shoots (multistemmed) to assess the influence of tree structure on the studied parameters, as well as distinguishing pear plants occurring before or after 1992. Pyrus plants significantly increased soil fertility compared to grassland, with a higher effect of the single trunk than stumps, while plant age seemed to play a minor role. Conversely, a multi-stemmed tree structure may be beneficial for protecting juveniles woody plants from browsing damage. Our results suggest that Pyrus spinosa can represent an excellent species to significantly improve soil conditions and trigger the restoration of woodlands in Mediterranean areas.