Soil properties discriminating Araucaria forests with different disturbance levels

Soil biological, chemical, and physical prop- erties can be important for monitoring soil quality under one of the most spectacular vegetation formation on Atlantic Forest Biome, the Araucaria Forest. Our aim was to identify a set of soil variables capable of discrim- inating between disturbed, reforested, and native Araucaria forest soils such that these variables could be used to monitor forest recovery and maintenance. Soil samples were collected at dry and rainy season under the three forest types in two state parks at Sao Paulo State, Brazil. Soil biological, chemical, and phys- ical properties were evaluated to verify their potential to differentiate the forest types, and discriminant analysis was performed to identify the variables that most con- tributetothedifferentiation.Mostofphysicalandchem- ical variables were sensitive to forest disturbance level, but few biological variables were significantly different when comparing native, reforested, and disturbed for- ests. Despitemorethan20years following reforestation, the reforested soils were chemically and biologically distinct from native and disturbed forest soils, mainly because of the greater acidity and Al 3+ content of reforested soil. Disturbed soils, in contrast, were coarser in texture and contained greater concentrations of ex- tractable P. Although biological properties are generally highly sensitive to disturbance and amelioration efforts, the most important soil variables to discriminate forest types in both seasons included Al 3+ ,M g 2+ , P, and sand, and only one microbial attribute: the NO2 − oxidizers. Therefore, these five variables were the best candidates, of the variables we employed, for monitoring Araucaria forest disturbance and recovery.