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Published online Nov 5.
This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license http: This article has been cited by other articles in PMC. Abstract In many European estuaries, extensive areas of intertidal habitats consist of bare mudflats and sandflats that harbour a very high abundance and biomass of macrobenthic invertebrates.
The high stocks of macrobenthos in turn provide important food sources for the higher trophic levels such as fish and shorebirds. Climate change and associated sea-level rise will have potential to cause changes in coastal and estuarine physical properties in a number of ways and thereby influence the ecology of estuarine dependent organisms.
Although the mechanisms involved in biological responses resulting from such environmental changes are complex, the ecological effects are likely to be significant for the estuarine benthic macrofauna and hence the consumers they support.
This paper reviews the utilisation patterns of estuarine intertidal habitats by shorebirds, fish and crustaceans, as well as factors affecting the distribution, abundance and biomass of estuarine macrobenthos that is known to be important food source for these estuarine predators.
This study also provides simple conceptual models of the likely impacts of sea-level rise on the physical and biological elements of estuarine intertidal habitats, and implications of these results are discussed in the context of sustainable long term flood and coastal management in estuarine environments.
Introduction Estuaries are ecologically important coastal environments situated between freshwater rivers and the sea, characterized by highly varying physicochemical, morphological and hydrological conditions [ 12 ], which exhibits some of the most biologically productive habitats on earth [ 34 ].
These habitats have long been known as important nurseries for species of fish and crustaceans [ 567 ], and estuarine intertidal sand- and mud-flats are of great conservation value because they often serve as vital feeding grounds for many wintering shorebirds [ 891011 ].
Estuaries have also been used as repositories for the effluent of industrial processes and domestic waste [ 4 ], and also prime sites for land reclamation for industrial or agricultural lands [ 45 ].
They are also natural sinks for contaminants, such as agricultural biocides and nutrients, originating from the catchment hinterland [ 312 ]. Estuaries and their fringing wetlands or low-lying hinterlands are important habitats for wildlife, but at the same time under ever increasing pressure from anthropogenic activities, and they are likely to continue to experience a diverse range of environmental stressors such as habitat loss, habitat alteration, eutrophication, overfishing and freshwater diversion.
Furthermore, warming of the global climate system is now evident with the linear warming trend over the 50 years between and nearing twice that for the year between and [ 13 ] and this is likely to cause the present rate of sea-level rise to increase [ 14 ], posing additional concerns for coastal and estuarine environments.
Amongst the most serious issues relating to climate change are increased flood risks resulting from rising sea levels, threats to the maintenance of coastal hard defences induced by increased wave and tidal energy and the process of coastal squeeze by which the area of intertidal habitats is reduced as the beach is prevented from migrating inshore due to the physical presence of hard coastal defences.
Sea-level rise will therefore undermine the welfare of both wildlife and human society around estuarine environments, so that management decisions will have major implications for the health of both estuarine ecology and society.
This paper considers the implications of climate change and associated sea level-rise for estuarine and coastal management on time scales of decades up to a century medium- to long-term with particular reference to the ecology of macrofauna on an estuarine intertidal habitat.
This study first reviews the utilisation patterns of estuaries by shorebirds, fish and crustaceans, as well as factors affecting the distribution, abundance and biomass of estuarine intertidal macrobenthos that is an important food source for those predators.
This is followed by a brief account of the most likely sea-level rise scenarios and an account of the likely impacts on the physical elements of coastal and estuarine ecosystems. Simple conceptual models are then presented to consider the likely impacts of climate change and sea-level rise on the physical and biological properties of estuarine intertidal habitats with reference to a case study of macrobenthic biomass in relation to changes in sediment particle size, beach morphology and salinity regime in the Humber estuary, UK.
How changes in other environmental parameters such as ambient temperatures or nutrient loading may interact with the effects of sea-level rise to shape the structure and function of invertebrate assemblages is also considered.
Finally, the adaptive strategies likely to be adopted to cope with sea-level rise are discussed and implication is given as to how to identify appropriate ecological objectives for sustainable shoreline schemes in estuarine environment in the future.
Estuarine Benthic Macrofauna and Their Predators In coastal and estuarine ecosystems, birds are often regarded as top predators and fish occupy intermediate trophic levels, both of which are supported by a large amount of intertidal benthic macrofaunal prey.
The high benthic biomass is a reflection of the presence of extensive intertidal flats and fine sedimentary deposits created through processes such as tidal asymmetry and flocculation [ 15 ].
Typically, there are coarser deposits on relatively exposed areas around the outer reaches and finer particles in sheltered areas as well as in the upper reaches of estuaries, depending on the local hydrographic regime and chemical processes.
Fine muds and silts provide a large surface area for the accumulation of organic matter and microbial processes, which in turn allows intertidal mudflats to support a high invertebrate biomass, especially with deposit- and filter-feeding taxa [ 151617 ].
Much of the interest from conservation and management agencies in evaluating the effects of sea-level rise on estuaries lies in the potential impact on these higher trophic levels, especially migrating shorebirds [ 1819 ]. In NW Europe, particularly dependent avian species are brent geese, shelduck, pintail, oystercatcher, ringed plover, grey plover, bar-tailed and black-tailed godwits, curlew, redshank, knot, dunlin and sanderling, whilst grey geese and whooper swan may utilise this habitat for roosting [ 1820 ].
Except for some herbivorous and omnivorous species such as brent goose, mallard or golden plover, many of shorebirds feed mainly on intertidal organisms when the flats are exposed, and they can be highly selective both as to where they feed and the size of prey, in order to maximise their efficiency [ 22 ].
Differences in food availability account for a large proportion of the variation in densities of bird feeding in intertidal habitats [ 1023 ], and shorebirds tend to concentrate where prey density and availability are relatively high and the energy expenditure required to feed is relatively low [ 24 ].
Intertidal flats within an estuary exhibit significant spatial variations in macrofaunal species composition, density and biomass, and this is highly correlated with substratum type or sediment particle size [ 25 ].
Thus, Yates and colleagues [ 10 ] were able to show that broad sediment characteristics can be used to predict the densities of shorebirds, allowing bird distributions to be predicted from sediment maps derived from remote sensing data.
If the size of feeding ground and the distribution of sediment types change with increasing sea levels, there is likely to be a response in bird distribution and abundance. This has indeed been the case where change in substratum type or loss of intertidal habitat has occurred.
For instance, the spread of the cordgrass, Spartina anglica, over the mud flats in southern England resulted in reductions in the numbers of Dunlin using affected areas [ 26 ]. Similarly, due to the impact of habitat loss as a result of land-claim on the intertidal area of the Forth estuary, Scotland, significant declines were noted for overwintering populations of dunlin and bar-tailed godwit [ 5 ].Here are 9 species that are already being impacted by climate change.
9 animals that are feeling the impacts of climate change | U.S. Department of the Interior Skip to . Global warming can affect saltmarshes in two broad ways, through change in the climate and by sea-level rise. Climate change Bertness and Pennings () argued that the zonation of saltmarsh plants might be influenced by nutrient enrichment (eutrophication) and by climate.
Impacts of Climate Change in the North East A short guide Briefing February How will climate change affect the UK? • The UK climate has warmed by nearly °C over the last years, with half of that. We are fully aware of the major changes in land cover throughout the continent, and we need to further examine the impacts on habitat quality resulting from the urban sprawl that affects surprisingly large portions of the landscape of eastern and central North America, and the effect of these impacts on natural populations, including birds.
THE EFFECTS OF GLOBAL CLIMATE CHANGE ON THE FISHES OF THE SOUTHEASTERN UNITED STATES given rise to the most diverse fish community in North America (Warren et al.
). For example, a square quadrat ( miles on a side) containing eastern Tennessee and western fisheries of the southeastern United . Many coastal wetlands can adjust to predicted climate change, but human impacts, in combination with climate change, will significantly affect coastal wetland ecosystems.
abundance of salt marshes has a direct effect on growth and recruitment of goslings and ultimately, plays an important role in regulating size of local brant populations. Keywords: brant, Branta bernicla hrota, Branta bernicla nigricans, breeding, climate change, migration. THE EFFECTS OF GLOBAL CLIMATE CHANGE ON THE FISHES OF THE SOUTHEASTERN UNITED STATES given rise to the most diverse fish community in North America (Warren et al. ). For example, a square quadrat ( miles on a side) containing eastern Tennessee and western fisheries of the southeastern United . Global warming can affect saltmarshes in two broad ways, through change in the climate and by sea-level rise. Climate change Bertness and Pennings () argued that the zonation of saltmarsh plants might be influenced by nutrient enrichment (eutrophication) and by climate.
Management for climate change must strike a balance between that which allows pulsing of materials and energy to the ecosystems and promotes ecosystem goods and services, while protecting human structures and activities.