Biological activity in Cerrado soils: evaluation of vegetation, fire and seasonality effects using the “bait-lamina test”

Abstract

Aims The Cerrado, a South American savanna, is considered a priority for conservation. In this case study, we assessed soil feeding activity as a way to improve understanding of the ecosystem functioning, in order to support and refine conservation strategies. Methods Soil feeding activity was assessed using the bait-lamina method under different environmental conditions: in the dry and rainy seasons, in burned and unburned areas, and under native and invasive grasses. Results Feeding activity was significantly reduced after fire, but recovered to pre-fire levels with the rains. Activity increased significantly during the rainy season in both areas, being more pronounced in the unburned area. The highest feeding activity was observed under the invasive grass (Melinis minutiflora). Feeding activity declined with soil depth and was affected by season and fire. Conclusions Seasonality was the most important factor affecting the feeding activity of soil organisms, followed by the fire history and the extant vegetation. Although this method does not allow distinguishing between feeding activity of different organisms, it can provide valuable insights into differences in soil functioning due to changes in environmental conditions.

Soil Biological, Chemical, and Physical Properties After a Wildfire Event in a Eucalyptus Forest in the Pampa Biome

“…The mean feeding activity of organisms in the soil was 34, 30, and 34 % for NP, EF, and AWF, respectively (Figure 3). Feeding activity in the current study is quite close to that observed by Musso et al (2014) in two different seasons in burnt and unburnt areas covered by native grasses and by invasive plant species in the Brazilian Cerrado. The effects of different uses of soil and of fire on the soil organisms activity were significant in the soil surface (up to the 0.02 m depth) ( Figure 3).…”

Experimental burns in an open savanna: Greater fuel loads result in hotter fires

“…Finally, although rarely registered, high temperatures belowground may occur with greater fuel loads. Even though underground buds and seeds buried in the soil are usually protected from such heat exposures, the effects of high temperatures on buds located in the upper soil layers and on the soil microbiota remain poorly understood in the Cerrado and should be the subject of future research (but see Musso et al 2014). Thus, despite fire intensity being a useful parameter to control fire propagation, we highlight the importance of measuring belowground temperatures in surface fire systems in order to better understand the effects of fire on post-fire regeneration.…”