ROTTERDAM, the Netherlands — Like many Muslims, Ahmed Aboutaleb has been disturbed by the angry tenor of the Dutch election campaign. Far-right candidates have disparaged Islam, often depicting Muslims as outsiders unwilling to integrate into Dutch culture.

It is especially jarring for Mr. Aboutaleb, given that he is the mayor of Rotterdam, a fluent Dutch speaker and one of the country’s most popular politicians. Nor is he alone: The speaker of the Dutch Parliament is Muslim. The Netherlands also has Muslim social workers, journalists, comedians, entrepreneurs and bankers.

“There’s a feeling that if there are too many cultural influences from other parts of the world, then what does that mean for our Dutch traditions and culture?” said Mr. Aboutaleb, whose city, the Netherland’s second largest, is 15 percent to 20 percent Muslim and home to immigrants from 174 countries.

Wednesday’s elections will begin Europe’s year of political reckoning. The Dutch race, coming ahead of others in France, Germany and possibly Italy, will be the first test of Europe’s threshold for tolerance as populist parties rise by attacking the European Union and immigration, making nationalistic calls to preserve distinct local cultures.