The temporal distribution of water-soluble nutrients from high mountain soils following a wildfire within legume scrubland of Tenerife, Canary Islands, Spain

• Soil pH, EC and basic cations increased 3 months after the fire, and decreased thereafter.
• Soil nitrates increased linearly with time in both burned and unburned samples.
• Ammonium increased in the burned samples fifteen months after the fire.
• Nutrient levels were higher in burned samples except for sulfates and phosphates.
• Our results suggest the possibility of moderate to low nutrient losses by erosion.

The concentrations of soil water-soluble elements (Ca2 +, Mg2 +, K+, NH4+-N, NO3−-N, SO42−-S and P), pH and electrical conductivity (EC) were monitored over a 15-month period after a wildfire that burned nearly 7 ha of high mountain broom scrubland in Tenerife (Canary Islands). The results showed that the mean values of soil pH, EC and basic cations were significantly higher three months after the wildfire in the burned area than in samples collected at adjacent, unburned sampling sites, and gradually decreased thereafter. The nitric-N increased consistently and linearly in time after the wildfire in all the samples, more intensely inside the burned area. Mean ammonium-N levels were nearly constant in burned and unburned samples almost across the entire study period, and increased in the burned area fifteen months after the fire. Sulfate-S and P showed no significant variations based on sample status (i.e., burned or unburned) or sampling time, possibly because of their particular dynamics in volcanic soils. These results point to a limited loss of nutrients, therefore suggesting that the possibility of intense post-fire erosion will be low. The nutrient levels found by the end of the study period were high enough to support the re-establishment of vegetation; however, the effect of alien herbivores on broom seedlings could eventually lead to a progressive replacement of the legume scrubland in the burned area.