Suppressing antagonistic bioengineering feedbacks doubles restoration success

Abstract

Abstract. In a seagrass restoration project, we explored the potential for enhancing the restoration process by excluding antagonistic engineering interactions (i.e., biomechanical warfare) between two ecosystem engineers: the bioturbating lugworm Arenicola marina and the sediment-stabilizing seagrass Zostera noltii Hornem. Applying a shell layer underneath half of our seagrass transplants successfully reduced adult lugworm density by over 80% and reduced lugworm-induced microtopography (a proxy for lugworm disturbance) at the wavesheltered site. At the wave-exposed site adult lugworm densities and microtopography were already lower than at the sheltered site but were further reduced in the shell-treated units. Excluding lugworms and their bioengineering effects corresponded well with a strongly enhanced seagrass growth at the wave-sheltered site, which was absent at the exposed site. Enhanced seagrass growth in the present study was fully assigned to the removal of lugworms' negative engineering effects and not to any (indirect) evolving effects such as an altered biogeochemistry or sediment-stabilizing effects by the shell layer. The context-dependency implies that seagrass establishment at the exposed site is not constrained by negative ecosystem-engineering interactions only, but also by overriding physical stresses causing poor growth conditions. Present findings underline that, in addition to recent emphasis on considering positive (facilitating) interactions in ecological theory and practice, it is equally important to consider negative engineering interactions between ecosystem-engineering species. Removal of such negative interactions between ecosystem-engineering species can give a head start to the target species at the initial establishment phase, when positive engineering feedbacks by the target species on itself are still lacking. Though our study was carried out in a marine environment with variable levels of wave disturbance, similar principles may be expected to apply to other ecosystems that are inhabited by ecosystem engineers.

Unpredictability in seagrass restoration: analysing the role of positive feedback and environmental stress on Zostera noltii transplants

“…46 of 92 plots) (Reise ; Suykerbuyk et al . ). To control for sediment handling, sediment was removed and replaced in the same way in the bioturbation control plots.…”

“…Suykerbuyk et al . ). Juvenile and adult lugworms were divided by the diameter of the cylindrical shaped cast; rule of thumb: juvenile < diameter cast 1 mm < adult.…”

“…) and suppressing negative feedback from neighbouring ecosystem engineering species (Suykerbuyk et al . ) can promote fast and sustainable establishment of the target species, though site selection and timing remain critical for any restoration project (Halpern et al . ).…”

A Mixed Modeling Approach to Predict the Effect of Environmental Modification on Species Distributions

“…After a first trial, it is planned to regularly use dredge spoil dumped onto the tidal flats as nourishment [28]. Softer defense measures include artificially constructed oyster banks [59] and saltmarsh restoration [60]. The emphasis placed on these measures is related to the conservation goals, as legally fixed e.g.…”

Increasing the chance of a successful restoration of Zostera noltii meadows

“…Molenaar and Meinesz, 1995;Piazzi et al, 1998;Sánchez-Lizaso et al, 2009), whilst the restoration of Zostera noltii (e.g. Martins et al, 2005;van Katwijk et al, 2009;Suykerbuyk et al, 2012) and Cymodocea nodosa (e.g. Cunha et al, 2009) is less common.…”