Work

Prioritising investment in kelp forest restoration: A spatially explicit benefit-cost analysis in southern Australia

Year: 2025

Type: article

Abstract: Kelp forests are globally significant ecosystems providing critical ecosystem services, including fish production, nutrient cycling, carbon sequestration, and recreational benefits. However, widespread degradation caused by anthropogenic pressures has led to significant declines in kelp forests, necessitating cost-effective restoration strategies. This study performs a spatially explicit benefit-cost analysis of kelp forest restoration in southern Australia to explore how variations in costs and benefits can inform prioritisation of restoration strategies. We found that investing in kelp forest restoration at the broad-scale returns a positive benefit-cost ratio of 1.10 (where 1.0 is break-even), with an median cost, benefit, and net-benefit of $37,451 /ha, $35,920/ha, and -$2,520/ha respectively. There was substantial site-specific variation in the benefit-cost ratio (0.33 to 3.4), driven by variation in nitrogen storage benefits ($0 - $105,000 /ha). Costs of ecosystem restoration were calculated based on the time to cull overabundant sea urchins from each location and for active kelp restoration costs. For culling, this varied based on urchin density, the depth (dive time) and travel time to the site. Overall, while kelp restoration proves beneficial, realising its potential will require robust funding mechanisms (perhaps via market-based incentives), which are currently lacking. This research demonstrates how spatial prioritisation can guide investments in marine ecosystem restoration to maximise return on investment.

Source: Ecosystem Services

DOI: 10.1016/j.ecoser.2025.101739