Management regime influences the recovery of subtidal kelp forests following harvesting

Physical disturbances, especially those that reduce or remove foundation
species, have complex effects on ecosystem functioning. Evaluating
resilience to predict these impacts requires long-term research over large
temporal and spatial scales. This study investigates the recovery
of the subtidal kelp (Lessonia trabeculata) to simulated kelp harvesting
in areas under different fisheries management regimes (Territorial Use
Rights for Fisheries (TURF) versus Open Access (OA) sites) along the
Northern-Central Chilean coast. The managed TURF sites
demonstrated significantly faster recovery of adult kelp densities
following harvesting, while the less OA sites exhibited consistently lower
kelp densities and delayed recovery. However, the generality of this
pattern varied across regions. Morphological traits such as holdfast
diameter were larger at TURF sites, where kelp exhibited larger size.
Delayed size recovery was evidenced at OA sites. Herbivore
densities were higher in OA than in TURF sites, potentially contributing
to differences in kelp density, size and recovery. These patterns
highlight the interaction between herbivory and management efficacy.
Synthesis and applications: Our findings highlight the critical role of
local fisheries management in enhancing kelp recovery after harvesting.
The faster recovery of kelp at most TURF sites demonstrates how spatially
explicit management can buffer ecological impacts of herbivore density and
promote kelp recovery. To improve outcomes, managers should prioritize the
implementation and enforcement of management plans in the TURF to promote
herbivore control measures and invest in long-term monitoring programs to
support adaptive strategies that sustain kelp forests ecosystems and the
valuable services they provide to coastal communities.