Jozef Kaban, Head of Skoda Design, introduces Skoda Kodiaq at a news conference in Guangzhou, China November 17, 2016. REUTERS/Bobby Yip

FRANKFURT (Reuters) - BMW BMWG.DE has appointed 44-year-old Slovakian Jozef Kaban, to head up design at its main BMW brand, bringing the group's auto styling team back up to strength after suffering a string of departures.

Vehicle design has grown in importance as a differentiating factor for traditional carmakers who are increasingly under threat from start-up brands, and as stricter pollution rules make it harder to push engine horsepower as a key selling point.

BMW said Kaban will replace Karim Habib who left the company “of his own accord,” without elaborating further. BMW also promoted Domagoj Dukec to head the design for BMW’s “i” and “M” subbrands, the company said in a statement on Wednesday.

Kaban will report to Adrian van Hooydonk, who remains design chief at BMW Group, which also owns the Rolls-Royce and Mini brands.

BMW’s design department has suffered a string of defections. Anders Warming, the former head of design at Mini, left to join Borgward, while Benoit Jacob who worked as a designer at “i” quit to join Future Mobility Corp. Richard Kim, a former senior automotive designer at BMW who helped shape the i3 production car, now works as Vice President of Design at electric supercar firm Faraday Future.