Threats to Mudflats

A 2012 estimate found the extent of intertidal mudflats in the UK to be around 270,000 ha (Foster et al, 2013). Little is known about the exact status of mudflats in Scotland (i.e. increasing, stable, or decreasing), as there is a lack of baseline survey data to compare to. There are a number of pressures on intertidal mudflats including climate change, land claim for development, pollution, invasive species (e.g. cord grass Spartina anglica), and fishing/bait digging (BRIG, 2011; Lake et al, 2015). 

Key Threat: Climate change
Mudflats are impacted by climate change, with rises in sea levels and increasing frequency of extreme weather events changing the sedimentation patterns of mudflats and estuaries (BRIG, 2011). Exceptional high tides and wave energy can move sediment away from mudflats faster than it can accumulate, resulting in a loss of habitat. Loss of mudflats can have significant impacts on species which rely on the habitat such as birds feeding. Alongside this, a loss of mudflats can also mean coastal areas are less resilient to the impacts of climate change and are therefore more vulnerable to erosion and flooding (Foster et al, 2013). 

Key Threat: Coastal 'squeeze' and Land Claim
Coastal squeeze occurs when the rate of sea level rise is higher than the rate of sediment accumulation. Historically land has been 'claimed' along the coast for agricultural purposes, and more recently for urban and transport infrastructure or industry. As a result, artifical sea defences are often erected to protect these built-up areas. However intertidal mudflats are 'squeezed out' as a result from low water moving inland but sea defences stopping sediment and mudflats moving inland too as part of their natural processes and dynamics (BRIG, 2011; Foster et al, 2013; Lake et al, 2015).

Key Threat: Pollution
Intertidal mudflat pollution can come from a number of sources, such as agricultural run-off, industry, and urban areas (e.g. domestic effluents) (BRIG, 2011; Lake et al, 2015). As levels of pollution increase, this impacts the organisms within mudflat habitats. For example levels of bioturbation (where organisms burrow and transport sediments) are reduced with high pollution levels, which then has impacts on the sediment structure and stability of mudflats (Mazik & Elliott, 2000).