Lignotuber size of Erica australis and its relationship with soil resources

Abstract

Abstract. It has been proposed that resprouting after a disturbance would be favoured under conditions of low soil resource availability. In lignotuberous plants of Mediterranean‐type areas, successful resprouting after disturbances such as fire depends on the size of the lignotuber, but little is known about the role of soil resources in determining the relative size of this organ. In this work we tested whether the relative size of the lignotuber in the resprouting shrub Erica australis is related to the availability of soil resources. At each of 13 different sites in Spain, 10 plants were chosen and the sizes of their various parts (above‐ and below‐ground) measured. Additionally, at each site we evaluated soil fertility, foliar N and P concentrations and plant water potential in the middle of the summer. The relationships between lignotuber dimensions and the various plant parts were assessed. In all cases, significant differences between sites were found indicating consistent differences in lignotuber size across the range of plant sizes. This was particularly the case when lignotuber dimensions were expressed as a function of foliar biomass. Lignotuber dimensions relative to foliar biomass were positively correlated with soil pH and negatively with plant water potentials in midsummer. There were, however, no clear relationships between lignotuber relative dimensions and soil N and P contents or other measures of site productivity. In summary, lignotubers were not smaller at more productive sites, in fact they were relatively larger at sites where soils were less acidic, but where plant water conditions were less favourable. These findings contradict predictions made based on current theory on the role of soil fertility allocation to resprouting.

Resprouting in the Mediterranean‐type shrub Erica australis afffected by soil resource availability

“…In this regard, the development of relatively larger resprouting organs, eventually richer in storage compounds, would cause greater resprout density and growth at sites with a low resource availability compared to those with more available resources. Nevertheless, the relationship between soil resource availability and the relative size of the resprouting organ (the lignotuber) in plants such as Erica australis, a strong resprouter from the western Mediterranean, did not conform entirely to these predictions: while lignotubers were relatively larger in low water-availability sites, they were also larger at sites with higher soil pH, which were generally more fertile (Cruz & Moreno 2001).…”

Structural characterization of charcoal size-fractions from a burnt Pinus pinea forest by FT-IR, Raman and surface-enhanced Raman spectroscopies

“…Forest fires are considered a major disturbance in Mediterranean ecosystems because their intensity and frequency have increased disproportionately over the last few decades [1][2][3]. An obvious sudden effect of forest fires is the loss of some soil organic matter (SOM), and this loss can vary enormously depending on factors such as fire severity, soil properties, vegetation type and landscape morphology [4].…”

Changes in a Humic Cambisol heated (100–500 °C) under laboratory conditions: The significance of heating time

“…Forest fires are one of the main disturbances in Mediterranean ecosystems and their number, size and intensity have increased over the last few decades (Moreno et al, 1998;Cruz and Moreno, 2001). Wildfires can burn vegetation and litter, affecting the soil by different thermal gradients depending on heating duration, depth and fire intensity (Iglesias et al, 1997).…”