Catalina Ruz1, Pippa Moore2, Alejandro Pérez Matus1
1Pontificia Universidad Católica de Chile, Chile - 2Newcastle University, UK
Lessonia trabeculata forests play a crucial role as founder species in Chilean subtidal ecosystems, providing key ecosystem services. However, intensive extraction associated with the alginate industry significantly disturbs their resilience. In this study, we evaluated the recovery of L. trabeculata through a controlled experiment that considered different extraction intensities and scales.
The experiment was conducted in a management area (AMERB) in central Chile, where experimental blocks (n=4) were established at 12 m depth. In each block, five treatments were applied: total and partial removal (high: 100% and medium: 50% removal) in patches of 2 m and 4 m diameter, as well as a control without removal. For 18 months, the density of recruits, growth rates, and the effects on the sessile community of the subcanopy were monitored.
The results showed that the disturbance’s intensity and scale influenced the forest recovery’s speed. Patches with high removal and greater extension (4 m) showed a faster recovery in density and accumulated biomass. The growth rates of the remaining algae did not vary significantly between treatments, but not the growth of the recruits. However, as the extraction was more intense, the sub-canopy community showed a greater change, with increased cover of opportunistic species and a decrease in invertebrates.
These results highlight the importance of incorporating disturbance-specific characteristics into management plans, suggesting that reducing the intensity and scale of extraction can improve the resilience of these forests and ensure the sustainability of the L. trabeculata fishery.