We present adaptive sensing, an energy-efficient topology configuration method for environment monitoring using densely deployed wireless sensor networks. Adaptive sensing puts redundant nodes into passive mode as auxiliary nodes to be used later on, thereby extending the system lifetime. Sensor data is collected at powerful macronodes periodically and a low-order model is fitted to compute a prediction area for each sensor. This prediction area is used to measure the redundancy level of the sensors covered in it. The redundant nodes are put into passive mode by macronodes while keeping the distortion in the output low. We analyze the energy-distortion tradeoff in monitoring applications, introduce the adaptive sensing algorithm based on this analysis. We also include a performance study demonstrating the advantages of our approach based on simulation results.