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Testing alternate ecological approaches to seagrass rehabilitation : links to life-history traits
journal contributionposted on 06.12.2017, 00:00 by Andrew Irving, J Tanner, S Seddon, D Miller, G Collings, R Wear, S Hoare, M Theil
1. Natural resources and ecosystem services provided by the world’s major biomes are increasingly threatened by anthropogenic impacts. Rehabilitation is a common approach to recreating and maintaining habitats, but limitations to the success of traditional techniques necessitate new approaches. 2. Almost one-third of the world’s productive seagrass meadows have been lost in the past 130 years. Using a combined total of three seagrass species at seven sites over 8 years, we experimentally assessed the performance of multiple rehabilitation methods that utilize fundamentally different ecological approaches. 3. First, traditional methods of transplantation were tested and produced varied survival (0–80%) that was site dependent. Secondly, seedling culture and outplanting produced poor survival (2–9%) but reasonable growth. Finally, a novel method that used sand-filled bags of hessian to overcome limitations of traditional techniques by facilitating recruitment and establishment of seedlings in situ produced recruit densities of 150–350 seedlings m-2, with long-term survival (up to 38 months) ranging from 0 to 72 individuals m-2. 4. Results indicate that facilitating seagrass recruitment in situ using hessian bags can provide a new tool to alleviate current limitations to successful rehabilitation (e.g. mobile sediments, investmentof time and resources), leading to more successful management and mitigation of contemporary losses. Hessian bags have distinct environmental and economic advantages over other methods tested in that they do not damage existing meadows, are biodegradable, quick to deploy, and cost less per hectare (US$16 737) than the estimated ecosystem value of seagrass meadows (US$27 039 year-1). 5. Synthesis and applications. This research demonstrates how exploring alternate ecological approaches to habitat rehabilitation can expand our collective toolbox for successfully re-creating complex and productive ecosystems, and alleviate the destructive side-effects and low success rates of more traditional techniques. Moreover, new methods can offer economic and environmental solutions to the restrictions placed upon managers of natural resources.