Interactions between benthic macroinvertebrates and saltmarsh plants : consequences for saltmarsh restoration and the policy of managed realignment on the coast of SE England.

PhDOver the last half century, the saltmarshes of south east England have undergone an extensive decline, especially the pioneer zone vegetation. These losses have generally been blamed on coastal squeeze resulting from sea level rising against sea walls. There is little evidence to support this hypothesis however, and an alternative hypothesis, based on infaunal invertebrates preventing the establishment of saltmarsh plants was tested. In the managed realignment site at Tollesbury, and the other sites examined, the mudflat fauna was dominated by Nereis (= Hediste) diversicolor and Hydrobia ulvae. In laboratory experiments N. diversicolor and H. ulvae reduced the production of seedlings from seeds of Salicornia europaea agg.. Conversely the presence of S. europaea agg. significantly reduced the normal burrowing activity of N. diversicolor. Invertebrate exclusion experiments established at five sites in south east England facilitated colonisation by saltmarsh plants at some sites (Orplands, the Blythe Estuary, Wallasea Island and Maldon), by excluding large (>3cm) N. diversicolor. However, at the Tollesbury realignment site, the high rate of sediment deposition and the relatively long distance to a source of seeds prevented plant colonisation. This study supports the hypothesis that establishment of saltmarsh vegetation is prevented by infaunal invertebrates,particularly N.diversicolor, which exclude plants through bioturbation, herbivory and granivory. These interactions may help explain the loss of saltmarshes and will reduce the success of future managed realignment schemes which depend upon the colonisation of new intertidal areas by saltmarsh vegetation. Further management of realignment sites will be necessary to encourage saltmarsh development.Ministry of Agriculture, Fisheries and Foo

The interaction of marine fouling organisms with topography of varied scale and geometry: a review

Many studies have examined the effects of surface topography on the settlement behaviour of marine organisms and this article reviews these investigations with more emphasis on the effects of topography scale. It has been observed that macro topographies (1-100 mm) are generally favoured by marine fouling taxa and are unsuitable for antifouling applications. This is because macro topographies are usually large enough to fit fouling organisms and provide refuge from dangers in the marine environment. Micro topographies had only limited success at reducing fouling from a wide range of marine taxa. The antifouling performance of micro topographies (1 to ≤1000 μm) is dependent on the properties of topography features in terms of symmetry, isotropy, width, length, height/depth, separation distance and average roughness. In terms of the antifouling performance of micro topography, topography geometry may only be of secondary importance in comparison to the size of features itself. It is also noted that hydrodynamic stresses also contribute to the settlement trends of foulers on textured surfaces. Future studies on antifouling topographies should be directed to hierarchical topographies because the mixed topography scales might potentially reduce fouling by both micro and macro organisms. Patterned nano-topographies (1- ≤1000 nm) should also be explored because the antifouling mechanisms of these topographies are not yet clear

A critical review of microplastic pollution in urban freshwater environments and legislative progress in China: Recommendations and insights

Freshwater systems are vitally important, supporting diversity and providing a range of ecosystem services. In China, rapid urbanization (over 800 million urban population) has led to multiple anthropogenic pressures that threaten urban freshwater environments. Microplastics (<5 mm) result from intensive production and use of plastic materials, but their effects in urban freshwater environments remain poorly understood. Rising concerns over the ecological effects of microplastics have resulted in increased attention being given to this contaminant in Chinese freshwater systems. Some studies provide quantitative data on contamination loads, but in general relevant knowledge in freshwater environment remains narrow in China, and lacking adequate understanding of threshold levels for detrimental effects. Notably, non-standardized sample collection and processing techniques for point and non-point sources have hindered comparisons of contamination loads and associated risk. Meanwhile, legislative frameworks for managing microplastics in China remain in their infancy. This manuscript critically reviews what is known of the nature and magnitude of microplastic pollution in Chinese freshwater environments, and summarizes relevant Chinese legislation. It provides recommendations for improving the legislative framework in China and identifies research gaps that need to be addressed to improve management and regulatory strategies for dealing with microplastic pollution in Chinese urban freshwater environments

Ecosystem-based fisheries management: progress in the NE Atlantic

Fisheries management in the NE Atlantic has recently adopted a precautionary approach to setting catch limits. This has been accompanied by the development of more complex and multi-species modelling tools for predicting stock size and structure. The scientific community are now being asked to provide an 'ecosystem-based approach' to fisheries management. In this paper, we consider the science needs of this shift to a consideration of more complex systems to include both ecological and socio-economic components. At present, this involves use of the precautionary approach and multi-species management regimes, but will need to include multi-annual quota assessment, 'stake-holder' involvement and marine protected areas. How will these approaches sit together and how will science support them? As an example, we will consider what management of the North Sea demersal fishery may involve in 20 years time.ICES MPAs Genetic effects Effort control By-catch Sensitive habitats EIA

An ex ante ecological economic assessment of the benefits arising from marine protected areas designation in the UK

This paper presents an estimate of the benefits of the proposed designation of a network of marine conservation zones (MCZs) in English territorial and UK offshore waters. This ex ante analysis was undertaken as part of a cost-benefit evidence base to inform implementation of the proposed UK Marine and Coastal Access Bill. This Bill is part of an ambitious plan to designate and manage UK marine areas using an Ecosystems Approach. Benefits are measured in terms of anticipated increases in the value of ecosystem goods and services provisioned by MCZs relative to the counterfactual, i.e. no designation. The principal valuation and thus policy challenge is presented by the need to use benefits transfer in a context where biophysical provisioning functions are not well-developed, where there are gaps in the valuation literature related to temperate marine ecosystem goods and services, and where values (where available) are presented in aggregate terms. This paper develops and applies a methodology that first apportions these aggregate benefits across the diverse range of marine landscapes and habitats and then estimates the marginal benefit of protection. The value of benefits was calculated for three different configurations of MCZs under two different management regimes. We estimate a benefit range from designation of between £10.2 billion and £23.5 billion in present value terms, applying a 3.5% discount rate. The study questions the extent to which a defensible policy evidence base can be developed in the absence of primary valuation data and where benefit estimates are reported in aggregate terms.Marine protected areas Areas valuation Benefits transfer Ecosystem services approach