Impact Type: Deposition of pollutant
It has been demonstrated that anthropogenic acid deposition can significantly reduce levels of available calcium in soil and the abundance of calcareous items such as snail shells. Recent research in areas adversely affected by acid deposition in continental Europe has suggested that reduced calcium availability has resulted in an increased incidence of eggshell defects in small birds (Pyatt et al. 1998, Weimer & Schmidt 1998).
However, research by Ramsay & Houston (1999) in the UK failed to find evidence reduced calcium availability was causing egg shell defects in blue tits. Effects will be worse when there is no source of Ca2+ to replenish soil losses.
There are other possible cause of eggshell thinning such as POPs and heavy metals.
|Critical Load/ Level|
No estimate available