This enabled certain species and populations to remain relatively stable, in contrast to the situation in other areas of Western Europe where intensive agriculture, together with a less diversified but more fragmented landscape, has reduced their area of distribution. In Portugal, for example, storks have never abandoned the rooftops and belltowers of towns and villages.

Thus, despite the far-reaching changes that have occurred more recently, particularly in the area of agriculture, there is still a high degree of biodiversity with many unique bio-geographical features and a mix of elements from different origins.

The bat population includes more than twenty species; there is a great variety of endemic fish species; carrion-eating birds that have disappeared from a Europe that has tong cleaned up its land still live among the mountain crags; in the cereal-growing plains and plateaux, there are ’steppe birds’ of African-type distribution; and southern birds and mammals inhabit Mediterranean-type scrubland.

The animal species found on Portuguese territory are being adversely affected mainly by changes in their habitat caused by increasing pressure from certain agro-industrial practices, as well as from depopulation and consequent changes in land use. Intensive agriculture, monoculture tree plantations covering vast areas, continued urban expansion, enlargement of the highway network, and excessive hunting are yet more factors threatening the survival of certain species. Some populations, particularly of large mammal’s such as the wolf, are now confined to just one or two mountain areas.

Throughout Portugal´s territory, birds are undoubtedly the most visible examples of animal life. These unchallenged lords of the skies, both elusive and cosmopolitan species, are everywhere, though they may only reveal their presence by a glimpse of their silhouette or through their songs and calls. However, birds are just the most familiar aspect of a varied animal life that, for any number of reasons, is normally hidden from our view.

The contrasts found in vegetation throughout the country, the result of environmental conditions, have to some extent been blurred by human activities, and nowadays the type of plant cover owes more to introductions of species and other changes brought about by humans than to the original natural structure. There is a ’Mediterranean’ Portugal, mainly located to the south of the river Mondego, dominated by evergreen trees and shrubs such as cork oak, holm oak, stone pine, laurel, Kermes oak, strawberry tree, and gum cistus, together with more intensely cultivated species such as olive, fig, and almond; then there is an ’Atlantic’ Portugal, more similar to Central Europe, where deciduous trees predominate: sweet chestnut, Portuguese oak, elm, and ash, together with shrubs such as broom and heather.

Trees are the most important element in plant cover and the distribution of the main species gives a better understanding of the nature of the vegetation.

Deciduous oaks - Engtish, Pyrenean and Portuguese - thrive mainly in the northern half of the country, while among evergreen oaks, the cork oak prefers the Baixo Atentejo while the holm oak is found mainly in the east.

The sweet chestnut, a species whose area of expansion has shrunk as a result of land clearance for cultivation, excessive felling, and root rot disease, grows mainly in the north-eastern Trás-os-Montes region, but is also found in the south in the São Mamede and Monchique mountains.

Among Mediterranean-type fruit trees, carob, almond and fig grow mainly in the Algarve, although almond is also found in the Terra Quente of Trás-os-Montes and fig in the Tagus valley and in some areas of the Alentejo.

Olive trees, whose cultivation became widespread in the 19th century, grows in flat areas and on slopes up to 800 m, and can be found almost everywhere, but particularly in Trás-os-Montes, Beiras, central A|entejo and on the left bank of the river Guadiana.

Maritime pine, the most common tree in the country, can be found anywhere from coastal dunes to the higher parts of mountain areas, forming great forests north of the river Tagus and dominating the landscape in the Entre Douro e Minho region, part of the Beira provinces, and Estremadura. Stone pine grows most densely to the south of the Setúbal peninsula.

Eucalyptus is an exotic species introduced relatively recently (19th century) into Portugal. Due to its rapid growth and the quality of its fibres, it is much in demand for the paper pulp industry, the main reason for its rapid expansion.