riodic inundation is the main driver of habitat survival. Many waders rely on floodplains and their existence is under threat where the flooding has been reduced or halted altogether.
Changes in the physical aspects of a coastline caused by large projects, such as the development of a port, or smaller objects, like groins or barriers, can dramatically change the drift of sediments along the shoreline. This can impact on the formation and evolution of flats and spits which are often extensively used by foraging waders. In one instance in New Zealand a new port development changed the currents to such an extent that silt deposits to one side of the port all but ceased, this led to the erosion of that portion of the coast. Some important coastal lagoons which existed there, which had been separated from the sea by the sediment were lost and swallowed by the sea as the barrier diminished thus eradicating not one, but two vital wader habitats.
If predicted warnings are correct, the impact of climate change would be devastating to coastal environments as previously intertidal areas would remain permanently under water and with human structures along much of the coast, which we would obviously protect, there is no natural place for the intertidal area to advance into and mud flats would become an endangered environment.
Existing ports are being developed and expanded, often meaning that large areas of mud are removed to allow ships to enter the area. The same thing happens in small bays, which are often shallow and ideal feeding grounds for waders where marinas are constructed for privately owned boats and yachts.
We all love a beach, and being by the sea is the preferred place to live for many of us. In addition it is where many of us choose to spend our holidays. The result is that all those people wanting to be beside the sea need places to live, or stay temporarily, and the entire infrastructure that goes with that.
Coastal towns tend to spread along the coast rather than inland increasing the area of beach front that is compromised from the point of view of the natural world.
A secluded bay that becomes a promenade is no longer secluded. Either the birds that nested there before are forced to move on or stay and live in substandard conditions with increased disturbance and predator numbers, both the dogs and cats that the people bring with them deliberately and the rats, foxes and gulls that they attract inadvertently. Litter and pollution soon follow any development, at night light spills from the town alter the environment and provide light for predators to hunt by.
Coastal saltmarsh erosion
Saltmarshes provide a sponge to soak up tidal surges and storm floods. They naturally erode as the sea pounds them and as they retreat so the land behind them retreats changing the landscape in form if not structure. However sea walls and urbanisation prevent the saltmarsh from moving back into the land the result of that is the loss of saltmarsh and the sea reaching these unnatural barriers causing them damage.
Grasslands turned over to agriculture
Away from the acute crisis in the intertidal zone the change of land use for agriculture has, over the last few hundred years, had a more chronic effect; more like a death by a thousand cuts. The pace of this change has been accelerating at an alarming rate as nations become more developed, what were once pristine grassland habitats have been ploughed and converted to farmland and previously suitable wader habitats within farmed areas have been altered to allow greater yields.
Grasslands, such as the prairies and the Great Plains in North America, and the Pampas of South America were once important areas sustaining the huge flocks of Eskimo Curlews. The prairies also held healthy breeding populations of Mountain Plovers, which have been much depleted, and Long-billed Curlews which are retreating westwards. At least half of the Prairies are now under the plough and that which remains is seriously degraded by the lack of the great grazing herds of American Bison and the eradication of Prair