Good article here on the terrible state of demographics in Europe.
Immigrants to Europe will certainly change the civilization and cultures present there. As the children of the West continue to opt for comfort and worldliness their civilization will die with them. It will be replaced by the civilization(s) of those who inherit their lands.
London will become more and more like Lahore.
Madrid will become more and more like Morocco.
Paris will become more and more like Algiers.
I can't say I'm too sad about the death of Western Civilization though.
Immigrants and European Demography