Niamey, Niger ? The government of Niger on Tuesday ordered the expulsion of 150,000 Arab refugees from Chad and neighboring countries who have lived in this West African nation for decades.

Interior Minister Mounkaila Modi told The Associated Press that the drastic decision was taken because many of the refugees are livestock herders whose camels are destroying arid Niger’s fragile ecosystem, particularly water sources in short supply.

Many of the Arabs are nomads known as “Mohamides” who fled past conflicts in Chad decades before.

“We have decided, starting today, to expel these nomadic Arab ‘Mohamides’ to their home countries,” Modi told The Associated Press. “These foreigners have shown no respect to the rights of the natives and they’re putting pressure on pastures in this region … we can no longer accept seeing our ecosystem degraded by foreigners.”

He said the order would apply to around 150,000 Arabs in Niger from countries in the region, including Algeria, Libya and Chad.