Combined Effects of Wildfire and Vegetation Cover Type on Volcanic Soil (Functions and Properties) in a Mediterranean Region: Comparison of Two Soil Quality Indices

Abstract

Mediterranean regions are the most impacted by fire in Europe. The effects of fire on soil greatly vary according to several factors such as vegetation cover type, but they are scarcely studied. Therefore, this research aimed at evaluating the combined impacts of fire and vegetation on single soil characteristics and on the overall soil quality and functionality through two soil quality indices, simple additive (SQI) and a weighted function (SQIFUNCT). In order to reach the aims, burnt and unburnt soils were collected under different vegetation cover types (herbs and shrubs, black locust, pine and holm oak) within the Vesuvius National Park. The soils were analyzed for the main abiotic (water and organic matter content, total C, N, Ca, K, Cu and Pb concentrations, C/N ratio) and biotic (microbial and fungal biomasses, basal respiration, β-glucosidase activity) characteristics. On the basis of the investigated soil characteristics, several soil functions (water retention, nutrient supply, contamination content, microorganism habitat and activities), and the soil quality indices were calculated. The results showed that the impact of fire on soil quality and functionality was mediated by the vegetation cover type. In fact, fire occurrence led to a decrease in water and C/N ratio under herbs, a decrease in C concentration under holm oak and a decrease in Cu and Pb concentrations under pine. Although the soil characteristics showed significant changes according to vegetation cover types and fire occurrence, both the additive and weighted function soil quality indices did not significantly vary according to both fire occurrence and the vegetation cover type. Among the different vegetation cover types, pine was the most impacted one.

Impact of Anthropic Activities on Soil Quality under Different Land Uses

“…In fact, the intensity of management practice modified the accumulation of soil nutrients and pollutants, influencing the abundance and the activities of organisms [21]. Moreover, the vegetation cover had a direct effect on soil properties, increasing the organic matter content, changing the rhizosphere pH, modifying the mobility of soil elements, which, in turn, results in a high soil biodiversity and quality [16,29].…”

“…Because of the growing public interest in sustainability and the desire to determine effects of land use and management practices on soil resources, one of the most important goals for modern soil science is to understand and assess soil quality [26]. One way to integrate information from soil indicators into the management decision process is the use of a soil quality index, as a primary indicator of sustainable land management [27][28][29].…”

The combined role of plant cover and fire occurrence on soil properties reveals response to wildfire in the Mediterranean basin

“…The fire impact on soil microbial communities and their recovery rates might be also mediated by soil properties [25] and by plant-soil interactions [26,27]. In fact, bacteria are stimulated in soils covered by vegetation, that enhances water permeability and organic matter content, as compared to those in bare soils [28], and both symbiotic and saprophytic fungi are impacted by post-fire plant communities [29].…”

Neutral Sugar Content and Composition as a Sensitive Indicator of Fire Severity in the Andisols of an Araucaria–Nothofagus Forest in Southern Chile

“…forest landscapes in southern Chile and Argentina [1][2][3]. Wildfires profoundly impact soil properties [4], mostly by altering the thickness, extent and composition of soil organic matter (SOM) [5][6][7][8]. During a fire, the SOM may be affected differently at each mineral soil horizon.…”

“…If ligno-cellulosic-rich material is burnt, a considerable part of the aromatic C derives from carbohydrates, which are dehydrated and subsequently aromatized [15,16]. It has been shown that the extent of this phenomenon increases with the increasing soil temperatures reached during wildfires [8]. A fire-induced alteration is expected to have a long-term impact on the quality and quantity of different SOM fractions, since above-and belowground fresh C input is the main primary source of carbohydrates in the soil, and it represents a major energy source for microbial growth [17].…”