The Dons looked to have banished their relegation fears after lifting themselves out of the League Two drop zone with a fine run of form since the turn of the year.
But Saturday's defeat by fellow strugglers Barnet means they are still looking over their shoulder, hovering just three points above the bottom two.
"We have to pick the boys up so that they stay mentally and physically strong," said Ardley.
"We are capable of winning our last four games. We have to get back to basics in training during the week and we will be working incredibly hard to get what we need.
"We have a good bunch of lads and we cannot let all the good work we have done in the last few months go to waste.
"All the teams down there are in form now and we have to make sure that we do not lose form at a crucial time. We will do everything in our power to make sure that does not happen."