rnative is not a Big Mac and fries or a trip to the supermarket, the alternative is hunger. It is in these situations that conservation needs to deal with the underlying poverty before it can address the hunting issue. This has been done with some success in Bangladesh and Myanmar where hunting was a threat to the Spoon-billed Sandpiper.
The primary pollutants are sediment, fertilisers, pesticides, plastics, salinity, heavy metals, weeds, poorly oxygenated water and altered pH levels.
Even if the flow of a river is not altered in some unnatural way, causing pollution by sediments, direct pollution and changes to the chemical make-up of the water can occur. This happens especially where the water course receives water run-off from urban areas, run off from farmland (which includes grazing stock), or direct use of the water for flushing or cooling chemical treatment and sewage. This change in the water can be obvious with a reduction of the clarity of the water but much of it is unseen and undetected.
Although not an obvious source of pollution deforestation can affect the component parts of the water with increased sediment due to erosion and loss of water clarity. These higher deposits can increase saltmarsh build up, but the quality of the water, often poorly oxygenisated, may affect wader prey species or reduce the nitrogen uptake by microorganisms in the water and mud.
Recently it has become apparent that our over use of plastic, combined with careless and irresponsible disposal and a lack of recycling is causing one of the biggest pollution problems ever faced worldwide, especially in our seas and along our coasts.
Further pollution risks come from accidental spillages at sea and into water courses, illegal dumping and tank flushing and mining activities.
Much of the disturbance caused to waders is as a result of people partaking in recreational activities. Beaches are much favoured as playgrounds where quad bikes and other vehicles are driven and parked. Other activities such as dog walking (especially if dogs are off the lead), jet skiing, boating, kayaking, surfing, windsurfing, kite surfing, low flying aircraft, sunbathing, fishing, shellfish collecting, horse-riding, birdwatching and photography can keep birds from resting or feeding for periods of time. Away from the beach other activities can be detrimental to birds in their breeding grounds such as hill walking and off road vehicles.
Uncontrolled domestic animals such as dogs and cats can cause great loss or distress to ground nesting and roosting birds. Recently horse training on beaches has become a problem in some parts of Australia.
Loss of food supply
The principle cause of food shortage is habitat loss, and also climate change is having a greater effect but our direct actions can cause problems too. Shellfish, in uncultured populations, can become over harvested; this is one of the probable causes of the demise of the Canarian Black Oystercatcher.
Another excessive use of the fruits de mer was in the over exploitation of Horseshoe crabs in the Delaware Bay in North America for fishing bait. Stocks of these bizarre creatures fell drastically depriving migrant waders, which were heading for their breeding grounds, of vital feeding opportunities.
The destruction of fisheries also has a knock on effect on the balance of nutrients in the sea which can result in ecosystems collapsing.