The National Inventory of Landscapes in Sweden (NILS) is a sample-based, nationwide environmental monitoring program focused on biodiversity. NILS started in full scale in 2003 and is based at the Department of Forest Resources Management, SLU. The program includes all terrestrial environments in Sweden, including agricultural land, wetlands, urban environments, forests, and mountains. NILS is based on 631 permanent sampling squares of 1 km x 1 km (Fig. 4). Within each square, 12 sample plots are field surveyed and an air photo interpretation is done for the whole area. A more extensive air photo interpretation within wider squares of 5 km x 5 km is also planned. The program will have a rotation time of 5 years. Results from NILS are intended to follow up on the national environmental objectives, land use status and change, and the distribution and area of different biotopes (Table 4, #5.1). The NILS program is divided into several subinventories, i.e. the general landscape (Table 4, #5.1), the mountains (Table 4, #2.1), arable land (Table 4, #4.6), and wetlands (Table 4, #6.3).