engleski

Changes in soil texture after wildfire: effect of severity, vegetation type and time-since-fire in Mediterranean environment

Wildfires have provided regulatory services in many terrestrial ecosystems throughout history. Low severity fires promote rapid vegetation recovery, and generally have a neutral impact on most soil properties, while high severity fires have adverse effects on many soil properties that can cause permanent environmental degradation. The objective of this study was to determine the effect of wildfire severity (HS-high severity ; MS-medium severity ; C-unburned), vegetation type (Q- Quercus p. and J-Juniperus c.) and time-since-fire (3 days, 3, 6, 12, 18 and 24 months) on soil texture in calcocambisol. Soil sampling (0-5 cm, N=180) was carried out on 15 ha of fire affected mixed Quercus pubescens Willd. and Juniperus communis L. forest in Zadar County (Croatia). Soil texture was determined via the pipette-method as silty loam. The results showed that fire severity and vegetation type had significant impact on soil sand, silt, and clay fractions, while their variability over time was not significant (p<0.05). Changes in soil texture were more pronounced in samples under Juniperus c. than under Quercus p. species. Under Quercus p., only the sand fraction in HS increased significantly, while under Juniperus c., sand increased in HS, silt increased in MS, while clay decreased significantly in both MS and HS compared to C. We conclude that the post-fire increase of sand and silt is due to the aggregation of clay particles, and that soil texture, and particularly the clay fraction, was more resilient to post-fire changes under Quercus p. species because the well-developed root system helped retain soil moisture, mitigating the devastating effects of wildfire.

calcocambisol ; mechanical analysis ; soil degradation ; wildfire

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