The Recovery of Mediterranean Soils After Post-Fire Management: The Role of Biocrusts and Soil Microbial Communities

Abstract

Although Mediterranean ecosystems are adapted to fire disturbances, soils are prone to degradation. Therefore, post-fire forest management is a critical step for ecosystem recovery: it can either reduce soil degradation or add a new disturbance. Post-fire management in Mediterranean burnt forests includes interventions with contrasting approaches, including the management of burnt trees, soil protection, or practices devoted to ecosystem restoration via the improvement of components or processes in the affected ecosystem. The consequences of forest management on soils are complex, thereby, in the context of the intensification of fire events and climate change, understanding the response of key soil components in managed ecosystems is critical for prioritizing soil conservation. One interesting component in the early post-fire stages is moss biocrust. The rapid colonization of biocrust-forming mosses in early successional stages post-disturbance stabilizes soils in their most vulnerable period. However, it is completely unknown further implications as active agents in the recovery and resilience of soils, in the transient stage before vascular vegetation regrowth. In combination with the biocrust, the response of soil microbial communities to forest management is crucial for evaluating the soil recovery progress, given their active role in fundamental ecosystem functions. The additive consequences of fires and forest management on biocrust emergence or microbial composition and functionality are usually neglected in the investigation of post-fire systems, although of major relevance to support strategies to preserve soils against functionality loss.

Combined Use of a Bacterial Consortium and Early-Colonizing Plants as a Treatment for Soil Recovery after Fire: A Model Based on Los Guájares (Granada, Spain) Wildfire

“…Moreover, eight strains of this group were isolated from unburnt locations and three from burnt ones, the same number as in the ashes. In the sampling profile, the strains happened similarly in roots (10), top soil (10), and deep soil (7) samples. Interestingly, the strain Flavobacterium sp.…”

“…Interestingly, we were able to detect a decent amount of biofilm in most of the strains, however, only 24 (43%) were able to produce above a 0.55 (OD 550nm ), referential level of the high-producer strain Pseudomonas putida KT2440, which we used as a control for this test. Of these, 18 were isolated in unburnt locations, almost double compared to burnt locations (10). More than half of the strains isolated (5) from ashes were able to produce this level of biofilm.…”

“…Apart from the obvious effects on fauna and flora, the degradation and destruction of soils is one of the most serious issues for the Mediterranean ecosystem due to the extremely slow soil regeneration ratio [ 5 , 6 , 7 , 8 , 9 , 10 ]. This component is especially critical because it should serve as support to the recovery and re-colonization of the affected area.…”

Comparative Effects of Wild Boar (Sus scrofa) Rooting on the Chemical Properties of Soils in Natural and Post-Fire Environments of the Edough Forest Massif (Northeastern Algeria)

“…The results obtained in the post-fire environment, a few months after the fire, highlight significant differences between the values of the chemical parameters in the three analyzed zones (rooting, control, and ring). In the literature, it is well established that wildfires have an impact on the chemical properties of soils, especially in Mediterranean ecosystems [40][41][42]. Many studies indicate a substantial increase in nutrients immediately after a fire event [41,[43][44][45][46], caused by the combustion of vegetation and debris, which significantly affects their availability.…”

How Mediterranean Ecosystem Deals with Wildfire Impact on Soil Ecosystem Services and Functions: A Review

“…Given this, the potential post-fire forest management or handling becomes of great importance. In many cases, techniques such as logging and wood extraction with heavy machinery contribute to soil degradation, while others like "mulching" reduce it, despite not being a suitable measure for soil biodiversity and not being the best technique to apply in all cases [31][32][33]. Post-fire management should be carried out in specific areas that are more susceptible to degradation because the management choices we make can have both positive and negative impacts on the soil.…”