Working With Nature Approaches for the Creation of Soft Intertidal Habitats

Abstract

As the artificial defenses often required for urban and industrial development, such as seawalls, breakwaters, and bund walls, directly replace natural habitats, they may produce population fragmentation and a disruption of ecological connectivity, compromising the delivery of ecosystem services. Such problems have increasingly been addressed through “Working with Nature” (WwN) techniques, wherein natural features such as species and habitats are included as additional functional components within the design of built infrastructure. There now exists a convincing body of empirical evidence that WwN techniques can enhance the structural integrity of coastal works, and at the same time promote biodiversity and ecosystem services. While these benefits have often been achieved through modification of the hard surfaces of the coastal defense structures themselves, the desired ecological and engineering goals may often demand the creation of new soft substrates from sediment. Here we discuss the design considerations for creating new sediment habitats in the intertidal zone within new coastal infrastructure works. We focus on the sediment control structures required to satisfy the physiological and ecological requirements of seagrass and mangroves – two keystone intertidal species that are common candidates for restoration – and illustrate the concepts by discussing the case study of soft habitat creation within a major multi-commodity port.

Reactive persistence, spatial management, and conservation of metapopulations: An application to seagrass restoration

“…Although many meadows in the harbor returned to their prior cover within a number of years, as of 2022 some large meadows, including Pelican Banks (NP in Figure 4), have not fully recovered (McKenzie et al, 2021). As such, restoration interventions of Z. muelleri are presently being studied (Aiken et al, 2021; Jackson et al, 2021; Jackson & Millar, 2020; Tan et al, 2020) not only with intent to offset the loss of historical meadows through land reclamation but also to improve the recovery time (i.e., the resilience) of the network when subject to disturbances in the future. That the seagrass meadows of Port Curtis and Rodds Bay are intrinsically transient rather than permanent suggests such a restoration strategy based around minimizing the recovery time from disturbance rather than preventing extinction.…”

New Initiatives Improve Wetland Restoration Outcomes: Engineering with Nature and the Use of Natural and Nature-Based Features

“…Dredged material placement restored the islands spatial footprint, increased surface elevation, improved conditions for plant growth, and increased the capacity of the site capacity to protect coastal communities. This project demonstrates how EWN principles can deliver both ecological and engineering benefit, including flood risk reduction (Aiken et al 2021). These projects collectively highlight the benefits of deliberately integrating natural features and processes into wetland restoration design to improve environmental outcomes while increasing resiliency and the protection of both natural and built infrastructure.…”

“…During the past decade, the U.S. Army Corps of Engineers (USACE) has cultivated the EWN initiative (Figure 1), which promotes the intentional alignment of naturaland engineering processes to deliver economic, environmental, and social benefits efficiently and sustainably through collaboration (King et al 2020; https://ewn.erdc.dren.mil/). Internationally, similar initiatives such as Working with Nature (WwN) have been introduced (Aiken et al 2021). The integration of nature-based processes and features into project design is an essential component of the EWN and WwN approaches, which has shown utility in a variety of wetland restoration contexts.…”

The Green Infrastructure of Sandy Coastlines: A Nature-Based Solution for Mitigation of Climate Change Risks

“…Exploiting the natural resilience afforded by the 'green infrastructure' of coastlines can be considered as an example of a 'nature-based solution' (NBS) to coastal issues [69][70][71]. Many studies worldwide have discussed the advantages of NBS along coastlines and the emphasis has mainly been on sandy coasts, including beaches, sand dunes, saltmarsh and mangroves [15,56,69,[72][73][74], where there is a close relationship between climate forcing and sediment dynamic response [75,76]. In contrast, there is much less consideration of the application of NBS to rock coasts and none at all to the rapidly changing environments of deltas or arctic coasts.…”

“…For example, island restoration in Chesapeake Bay (MD, USA) used dredged sediment to build up island beaches, which increased the size and height of sandy landforms, increased vegetation biomass and decreased the efficacy of wave erosion [82]. NBS strategies have been particularly applied to coastal wetlands and intertidal environments which are sensitive to subtle changes in sediment supply and micro-elevation, with implications of high-biodiversity intertidal ecosystems [72,73,76]. These examples highlight the multiple benefits and the cost-effectiveness of NBS in certain types of coastal settings.…”