Question: Who replaced the English football manager Paul Buckle after he lead the Bristol Rovers through a disappointing season in 2011-2012?

Context paragraphs:
2011–12 Bristol Rovers F.C. season: During 2011 and 2012, Bristol Rovers Football Club participated in League Two, the fourth level of English football.  It was 129th season of football played by Bristol Rovers, and their 85th in the Football League.  The previous saw Bristol Rovers end a four-year tenure in League One.  Despite initial optimism of an instant return, the campaign proved disappointing as Rovers struggled for much of the season under new manager Paul Buckle before being replaced by Mark McGhee who brought about an upturn in fortunes to finish 13th.

2016–17 Bristol Rovers F.C. season: The 2016–17 season was the 134th season in Bristol Rovers' history and their 89th in the English Football League.  Following back-to-back promotions in 2014–15 and 2015–16, Rovers competed in the third tier of English football, League One.  What was a steady season, Rovers played the likes of Coventry and Chelsea (in the EFL Cup) for the first time in decades.  After a brief playoff push towards the end of the season, Rovers finished in a respectable 10th place with 66 points, their highest finish in the football league since the 1999-2000 season.

Paul Buckle: Paul John Buckle (born 16 December 1970) is an English football manager.  He has previously been the manager of Torquay United, Bristol Rovers, Luton Town and Cheltenham Town.  On 8 July 2015 it was announced he had signed as Head Coach of the USL soccer club Sac Republic FC.

Billy Bodin: Billy Paul Bodin (born 24 March 1992) is a professional footballer who plays for League One club Bristol Rovers.  He plays as a forward or as an attacking midfielder.  Bodin is the son of former Wales international and Swindon Town youth coach, Paul Bodin.  He spent the first half of the 2011–12 season on loan to Torquay United before returning to Swindon Town to score his first goal for the club.  He now plays for Bristol Rovers in League One.

Jimmy Morgan: William James Morgan (19 June 1922 – 11 October 1976) was a professional footballer who played in The Football League for Bristol Rovers immediately after the Second World War.  Jimmy was a member of the Barton Hill Morgan footballing family which included his uncles Jerry Morgan (Bristol Rovers), Tom Morgan (Bristol City), Fred Morgan (Bristol City) and Jim Morgan (Wolverhampton Wanderers).

Keith Williams (footballer, born 1937): Keith Williams (born 14 January 1937) is a footballer who played as inside forward for Everton, Tranmere Rovers, Plymouth Argyle and Bristol Rovers.  Williams joined Everton from school, but transferred to Tranmere in May 1957, joining his brother Ray there.  He scored 88 goals in 161 Football League appearances during his four seasons at Tranmere, but conflict with manager Walter Galbraith led to his being transfer-listed.  Williams moved to Plymouth at the end of the 1960–61 season, then to Bristol Rovers soon after.  He was then banned due to a bribes scandal.  In 1962, Keith moved with Ray to South Africa to set up business there.

History of Bristol Rovers F.C.: Bristol Rovers F.C. is an English football club based in the city of Bristol.  The history of Bristol Rovers covers the period from their formation in 1883 as the Black Arabs until the present day.  The club spent their early days playing matches that were arranged on an ad-hoc basis, not joining a formal league until becoming founder members of the Western League in 1892.  Full professionalism followed shortly afterwards, and in 1899 they were admitted to the Southern League.

2010–11 Bristol Rovers F.C. season: The 2010–11 season was Bristol Rovers fourth season in League One since being promoted via the League Two play-offs in 2006–07.  Bristol Rovers had a poor season and on 30 April 2011, they were relegated to League Two after a 1–1 draw with Sheffield Wednesday.  Bristol Rovers 2010–11 season officially began on 1 July 2010 and concluded on 30 June 2011, with competitive fixtures taking place between August and May.

List of Bristol Rovers F.C. players: Bristol Rovers Football Club is an English professional association football club based in Bristol, who play in Football League One, the Third tier of the English football league system, as of the 2016–17 season.  The club was formed in 1883 under the name Black Arabs F.C. playing their home games at Purdown in Bristol, but they used the name for only a single season, becoming Eastville Rovers and moving to a site known as Three Acres in 1884.  Eastville Rovers were somewhat nomadic, moving home in 1891 to the Schoolmaster's Cricket Ground, in 1892 to Durdham Down, and in 1894 to Ridgeway, before finally settling at Eastville Stadium and changing their name to Bristol Eastville Rovers in 1897.  Two years later they adopted their current name of Bristol Rovers when they became founder members of the Southern League.  They remained at Eastville Stadium for 99 years, before leaving in 1986 when financial pressures meant that they could no longer afford to pay the rent, whereupon they moved to Bath City's Twerton Park, a move that saved the club £30,000 a year.  After playing for ten years in Bath, the club returned to Bristol in 1997 when they agreed to share Bristol Rugby's Memorial Stadium.  Since joining The Football League in 1920, when the top division of the Southern League effectively became the Football League Third Division, Rovers have spent most of their time in the second and third tiers of the English football league system; the team has never played in the top flight and spent six years, 2001 to 2007, in the fourth tier.

2008–09 Bristol Rovers F.C. season: During 2008 and 2009, Bristol Rovers Football Club participated in League One, The 2008-09 season covers the period from 2008-07-01 to 2009-06-30.  It marks the 126th year of football played by Bristol Rovers F.C. and their 82nd season in The Football League.

Supporting paragraphs: 2011–12 Bristol Rovers F.C. season Paul Buckle
Answer: Mark McGhee