Prescribed fires as exclusion treatment for the invasive species Hakea sericea in Portugal.
The invasive species Hakea sericea is increasingly emerging after recurring fires in Portugal. Prescribed burning is a tool to reduce fuel loads and to control these invasive species. However, research on the effectiveness with respect to its control is hardly documented. In this area and within the framework of the Aliens and Flames (PDR2020-101-030919) and SusPiRe (PTDC/ASP-SIL/30983/2017) projects, the short-term influence was examined of two types of prescribed fire treatments: (i) Slash & Burn (cut and burn) vs. (ii) Burn (burning), at the plant community level, on the abundance of H. sericea and on the degradation of the soil via erosive processes. The short-term results showed that the relative abundance of H. sericea was slightly higher in the plots with the Burn treatment. In comparison with native vegetation such as Cistus spp., a relatively low number of H. sericea seedlings was detected. The continuation of this study is necessary to evaluate the development of these invasive species in the medium and long term. In the Burn treatment, a greater severity of the fire in the soil and a subsequent greater export of soil (both ash and organic matter) were observed, which could explain why the number of plant species in this treatment was lower. The Aliens and Flames project plans to study in depth the behavior of fire and its impacts on soil and vegetation to obtain a complete description of the effect of prescribed burns on invasive species such as H. sericea.