Role of Seasonality and Fire in Regulating the Enzymatic Activities in Soils Covered by Different Vegetation in a Mediterranean Area  
[PERSON]  
1 Dipartimento di Biologia, Universita degli Studi di Napoli Federico II, Via Cinthia, 80126 Napoli, NA, Italy; [EMAIL_ADDRESS] (V.M.); [EMAIL_ADDRESS] (G.S.); [EMAIL_ADDRESS] (P.M.); [EMAIL_ADDRESS] (G.M.)  
[PERSON]  
1 Dipartimento di Biologia, Universita degli Studi di Napoli Federico II, Via Cinthia, 80126 Napoli, NA, Italy; [EMAIL_ADDRESS] (V.M.); [PERSON] (G.S.); [PERSON]S] (P.M.); [PERSON]DRESS] (G.M.)  
[PERSON]  
1 Dipartimento di Biologia, Universita degli Studi di Napoli Federico II, Via Cinthia, 80126 Napoli, NA, Italy; [EMAIL_ADDRESS] (V.M.); [PERSON] (G.S.); [EMAIL_ADDRESS] (P.M.); [EMAIL_ADDRESS] (G.M.)  
[PERSON]  
1 Dipartimento di Biologia, Universita degli Studi di Napoli Federico II, Via Cinthia, 80126 Napoli, NA, Italy; [EMAIL_ADDRESS] (V.M.); [EMAIL_ADDRESS] (G.S.); [EMAIL_ADDRESS] (P.M.); [EMAIL_ADDRESS] (G.M.)  
Rosella Barile  
3 Parco Nazionale del Vesuvio, Via Palazzo del Principe c/o Castello Medico, 80044 Otraviano, NA, Italy; brahir  
of basic information regarding whether the critical drivers of seasonal soil enzyme activity differ among vegetation types [5].  
In Mediterranean regions, fires are among the main disturbance factors that cause deep changes in soil abiotic and biotic properties and alter soil quality [13; 14; 15; 16]. Fire effects on soil enzymatic activities are direct as they cause protein denaturation, temporary soil sterilization, and nutrient mineralization [17; 18], and indirect as they cause changes in soil microbial and plant communities [19; 20; 21; 22].  
Among the soil enzymatic activities, hydrolase, dehydrogenase, and \(\beta\)-glucosidase are good indicators of soil microbial activity [23; 24]. In fact, hydrolase, intermediating hydrolytic reactions, allows for the estimation of total soil microbial activity [15; 25]. In addition, extracellular hydrolytic enzyme activities (dehydrogenase and \(\beta\)-glucosidase) are strongly affected by fire, as reported by several authors in studied performed in boreal and temperate forests [2; 26; 27]. Dehydrogenase, oxidizing the soil organic matter by transferring protons and electrons from substrates to acceptors, is a well-known biological indicator of overall microbial respiratory activity [28]. \(\beta\)-glucosidase is involved in C mineralization and provides information on the degradation of cellulose, which is the most common polysaccharide in nature [29].  
Investigations about the relationships between temporal trend of soil enzymatic activities and soil properties can provide useful information not only for understanding the soil processes, but also for predicting their responses to environmental change [5]. As research focusing on the role of vegetation cover upon the soil enzymatic activities in areas affected by fire is scarce, the research aimed: (i) to evaluate the seasonal trends of enzymatic activities in unburnt and burnt soils covered by the same vegetation cover; (ii) to compare the role of each vegetation cover on soil enzymatic activities in unburnt and burnt soils; and (iii) to highlight, among the investigated abiotic soil properties, the main drivers of the soil enzymatic activities in unburnt and burnt areas. In order to achieve the aims, surface soils were collected under herbs, black locust, pine, and holm oak in unburnt and burnt soils inside the Vesuvius National Park located in the Mediterranean area of Southern Italy. The collected soils were characterized for the main abiotic soil properties (i.e., water and organic matter contents, pH, concentrations of C and N, and available fractions of Al, Ca, Cu, Fe, Mg, Mn, Na and Pb) and enzymatic activities (i.e., hydrolase, dehydrogenase, and \(\beta\)-glucosidase). The findings provide useful information about the integrated effects of seasons, vegetation cover, and fire occurrence on soil abiotic properties that, in turn, can drive the soil enzymatic activities.