Testing alternate ecological approaches to seagrass rehabilitation: links to life‐history traits

Abstract

Summary1. 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 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, investment of 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.

Maximising establishment success of Amphibolis antarctica seedlings

“…The energy needed to displace entangled seedlings is generally influenced by the strength of the material to which it was attached, whereas the force to dislodge a seedling from sand is influenced only by the weight of sand covering the comb anchor (Rivers et al, 2011). This supports observations of poor seedling transplant success into bare sand (Irving et al, 2010 andKirkman, 1998).…”

Harnessing Natural Recovery Processes to Improve Restoration Outcomes: An Experimental Assessment of Sponge-Mediated Coral Reef Restoration

“…For example, life history traits have been successfully used to improve restoration of seagrass meadows [74], and asexual reproduction has been linked to success, particularly in early stages of restoration [73]. Asexual reproduction dominates the life histories of erect branching sponges, and fragments of all three species attached rapidly to pieces of coral rubble, often in as little as two days (Table 5); rates in line with other erect branching Caribbean species ([20], [46], B.C.…”

“…Progress will best be made through experimentation and rigorous evaluation of alternative approaches, and shifting the balance may require incorporating natural processes that facilitate recovery into our restoration toolkit. Methods will necessarily need to be tailored specifically to the biology of the system under investigation [74]; however, as demonstrated here for coral reefs as well as in other systems, harnessing organisms that jump start successional pathways and facilitate recovery can significantly improve restoration outcomes [28], [37]–[40].…”

Identifying knowledge gaps in seagrass research and management: An Australian perspective

“…How important are sediment characteristics for successful restoration? Sediment is almost always critical for seagrass growth and persistence, but excessive deposition (turbidity), accumulation (plant burial), erosion, and re-suspension can impair seagrass restoration (Irving et al, 2010;van Keulen et al, 2003). Additionally, understanding the importance of sediment quality, such as organic and nutrient content, grain size distribution, sediment source, porosity, and microbial activity may improve restoration outcomes.…”