3.5 Impacts on ecosystems, natural and cultural landscapes, and historical relics

The cultivation of virgin or partly virgin land may conflict with the wish to preserve biological diversity, the conservation of continuous natural habitats for the benefit of wildlife, and the preservation of particular ecosystems and types of natural landscape. From an agricultural point of view, floodplains, river plains, swamps, and other biologically luxuriant areas may be attractive for cultivation. Such areas may, however, also represent unique habitats critical for the possibilities of survival to certain species of wild animals and plants. This type of conflict over the use of land must be treated with reference to the "Convention on biological diversity" (UNCED 1992).

Agriculture may affect the environment beyond cultivated areas through e.g. grazing, grass burning, felling, hunting, and gathering. Plant and animal life adapted to human activity over a long perioda of time may have developed, forming a valuable cultural landscape. The cultural landscape may be seen as a habitat of its own, and may contain a rich multitude of species. For example, traditional slash-and-burn farming in rain forests leads to a mosaic of small fields representing all the transitional stages of regrowth from recently abandoned fields to fully grown forest. These small patches are ecological niches for a great variety of plant and animal life. Agricultural development involving intervention in the cultural landscape should be weighed against the ecological function of the latter. The vegetation may e.g. offer protection against soil erosion and contribute towards stabilizing the water balance of the area. The cultural landscape may also supply vital contributions to the household. If these contributions are reduced or removed altogether, the pressure may increase on other resources, e.g. natural habitats worthy of preservation.

Measures within agriculture may change the visual content of the landscape. Considerate designing of plants and installations, as well as adaptation to and positioning in the landscape should be considered during the planning and implementation of the measures. For example, a lessening of the aesthetic pleasure offered by both the cultural and the natural landscapes may result from the levelling of slopes and removal of vegetation - undertaken with the objectives of making the use of land more effective as well as facilitating the use of modern farming equipment. At best, a project may contribute to enhance its beauty rather than destroy the landscape's content and positive value in terms of emotions and experiences. In general, farming activities have been maybe the most important former of the cultural landscape through the ages, and the impact of this influence has been positive as well as negative. Many cultural landscapes may be worthy of preservation due to visual qualities, and it should be remembered that the appearance of the landscape may in any case be very important for the local population's feelings of belonging to a specific area. Pilot surveys may be required in order to avoid conflicts.