In the latest upheaval in Warner Music Group’s executive suite, Warner/Chapelle topper Cameron Strang is adding responsibility for management of Warner Bros. Records’ senior exec staff.

WBR chairman Rob Cavallo and chairman-co-president-COO Livia Tortella will now report directly to Strang, who will now be head of the label’s West Coast operations. In announcing Strang’s new duties, WMG also said that WBR co-president-CEO Todd Moscowitz has decided to resign. No replacement was immediately named.

Strang’s executive star has been on the rise at WMG for two years. He was named chairman of Warner/Chappell in January 2011 and took charge of the newly established publishing and catalog unit when the company was restructured divisionally early last month.

Since September, when WMG recorded music chairman Lyor Cohen ankled the company, Cavallo and Tortella had reported to WMG CEO Stephen Cooper.

The heads of WMG’s other label units — Atlantic Records Group chairman-CEO Craig Kallman and chairman-COO Julie Greenwald and Warner Music Nashville prexy-CEO John Esposito — currently report to Cooper.

The supervision of WBR’s music toppers by Cooper — a corporate mop-up specialist with no prior music biz experience who was installed by Len Blavatnik after the Russia-born industrialist’s Access Industries bought WMG last year — lasted less than a quarter.

Strang founded Southside Independent Music Publishing, which was acquired by Warner/Chappell in 2010, and was formerly head of the L.A.-based independent Americana label New West Records.

Cooper said in a statement, “Since joining WMG, Cameron has demonstrated strong leadership, both in the revitalization of our Warner/Chappell music publishing arm as well as through his service on the WMG Board of Directors. He has broad knowledge of both the music publishing and recorded music businesses, combined with an entrepreneurial drive and progressive vision for the role of music companies.”

Moscowitz becomes the first Cohen loyalist to exit WMG since the music topper’s fall departure. He was one of Cohen’s key lieutenants as GM of Def Jam Records, and had risen up the ladder within WMG during Cohen’s eight-year tenure there.

“I want to thank Todd for all of his contributions to WMG since 2004,” Cooper said. “During his tenure at Warner Bros. which began in 2010, Todd has been instrumental in bringing new talent and energy to the label.”