According to director Michael Bay this will be the location of a heroic turning point scene, which takes place after the fall of Hong Kong. A group of Transformers will meet up with another group Transformers where they battle their way out of a crater (Wulong Karst is known for it's sink holes) that was apparently created by a crashed starship. After the Wulong Karst battle they return to Hong Kong.
Here's a few images from the filming in Wulong Karst from Bay's website:



Sources:
http://news.66wz.com/system/2013/10/31/103862540.shtml
http://ent.yunnan.cn/html/2013-10/31/co ... 939763.htm
http://news.gmw.cn/newspaper/2013-10/31 ... 340944.htm
http://www.ecns.cn/2013/10-30/86451.shtml