Any subdivision or site plan approval shall expire within two years from the date of final plat approval unless construction shall have been actually commenced on those improvements, whether on-tract, off-tract, on-site or off-site, required as part of the approval, as a condition of the approval or shown on the plan presented for approval or plan revised in accordance with the approval. Said improvements shall include but not be limited to streets, grading, pavement, gutters, curbs, sidewalks, streetlighting, shade trees, surveyors' monuments as required by the Map Filing Law, water mains, culverts, storm sewers, sanitary sewers or other means of sewage disposal, drainage structures, erosion control and sedimentation control devices, public improvements of open space and, in the case of site plan only, other on-site improvements and landscaping. If the performance bond covering any of the above improvements expires prior to the two-year period following final plat approval without completion of the aforesaid improvements covered by the bond, the approval shall expire with the expiration of the bond.