This management plan was based on a combination of biodiversity conservation and wilderness protection approaches. The plan was based on an up-to-date synthesis of all information and literature available about the protected area. Human geography Although there has been variable growth throughout the Norte region, there has been a general population decrease in those administrative units that fell within the Peneda-Gerês National Park (1981–1991), in the municipalities of Melgaço (-16.8%), Arcos de Valdevez (-13.4%), Ponte da Barca(-6.1%), Terras de Bouro (-7.2%), and Montalegre (-20.3%). There was a population of 9,099 according to the 1991 census, a 16% decrease from the 10,849 registered in 1981. There are no positive-negative variations between civil parishes; of those civil parishes that fell within the PNPG authority, their populations dropped from 0.8% (Vilar da Veiga) to 38.6% (Sezelhe). These residents are concentrated primarily in various agglomerations: small nuclei separated from each other; an extension of buildings located along roadways; some isolated groups; constructions along agricultural roads in pasturelands; and three or more homes isolated by pastures. Consequently, there are six homogeneous zones: Castro Laboreiro and Rio Laboreiro Valley - consisting of small agglomerations separated by short distances. It was still common practice for the residents of mountain communities to spend part of the year in two locations, primarily near Castro Laboreiro. From about Easter to about Christmas, residents would live in homes above 1,000 m above sea level, known as branda (from the Portuguese brando, meaning mild or gentle). In the remaining part of the year, these inhabitants would occupy homes in the river valley, known as inverneira (from the Portuguese Inverno, meaning winter); Serras da Peneda and Serras do Soajo - small pastoral agglomerations, with different summer and winter residences; Lima Valley and Serra Amarela - where the Lima Valley consists of two or more agglomerations connected by lines of residences between them, while in the Serra Amarela populations are concentrated in isolated pockets; Gerês Valley - development of tourism, around the Caniçada Dam and Thermal baths, resulted in uncontrolled re-construction, re-modelling and expansion of existing residences, although there already existed a tendency for expansion along the avenues and accessways along the valley; Cabril-Gerês - steep areas along the River Cávado and Salamonde Dam, where buildings are concentrated along the accessways, and Cabril River, with pasturelands located between agglomerations; Mourela/Barroso Plateau - extending south, southeast and southwest, the plateau is a series of agglomerations,