Recreation and tourism are becoming popular to the extent that in many countries they have developed into a national industry; they are often accompanied by extensive damage to the environment. Aquatic ecosystems are particularly vulnerable to the effects of an increased tourist trade and the resultant building of hotel accommodations, sewage disposal works, roads, car parks and landing jetties on banks and coastlines; and the increased angling, swimming, water skiing, shooting or use of motor-boats in the water body. These all produce direct deleterious effects when conducted on a massive scale, including shore damage, chemical changes in the water, and sediments and biological changes in the plant and animal communities. Indirect effects are caused when small towns and villages near a water body are visited periodically by a large number of people; or by changes in the land usage within the drainage area often due to an increase in industrial sewage or agricultural run-off that is associated with the local growth of tourism.
Environmental disadvantages accompanying the over-exploitation of tourism include: despoiling of coastlines by construction of tourist facilities; pollution of the sea; loss of historic buildings to make way for tourist facilities; loss of agricultural land for airport development. Ownership of land and the control of components of the tourist industry are increasingly in the hands of non-residents and of companies based elsewhere, giving rise to serious problems of control. Often outside interests acquire the best sites and beaches and then exploit them in such a way that an overall tourist plan cannot be implemented at a later date.
Tourism places direct and indirect pressures on, and threats to, the conservation of species and habitats, and may cause disturbances to wildlife and increase pollution caused by transportation.
Disposal of waste produced by the tourism industry may cause major environmental problems. Such waste can generally be divided into: sewage and waste-water; chemical wastes, toxic substances and pollutants; and solid waste (garbage or rubbish). The effect of direct discharge of untreated sewage can lead to eutrophication, oxygen deficit and algal blooms.
The Mediterranean is a prime example of the consequences of the over-development of a natural asset (namely the coast) for tourist purposes. Every one of the 6,000 registered beaches in Italy is dangerously polluted according to standards decreed by the Italian government (some have bacteria counts 5 times higher than the limit). Hundreds of miles of coastline have been irremediably ruined by the virtually uncontrolled building of hotels, restaurants, bars and houses. Beaches have been divided into unsightly allotments, and noise from juke boxes, fumes from traffic and sheer human overpopulation have all become indicative of the consequences of over-exploitation of tourism. On a particular 40-mile stretch of the French coastline there are 195 open drains discharging untreated sewage straight into a tideless sea. France's Camargue, Spain's Coto de DoÃ±ata and Greece's Amvrakikos Gulf have become battle-grounds between environmentalists and developers. Delivery vehicles involved with the building of new tourist facilities on a Turkish coast repeated drove over a nesting beach for turtles during their breeding season. Tourists stroke and cuddle turtles during their egg-laying trips at night.
Another area of recent ecological concern is the Alps, particularly the regions and surrounding woodland regions of popular ski resorts. According to a 1991 report, an estimated 120,000 tourists flock to the Alps every year. By the end of 1990, there were 40,000 ski runs in the Alps and plans to build more. Since Alpine traffic increases at the rate of 5% a year, an estimated 10 new tunnels will be needed by the year 2020 to sustain the influx. A 1992 study shows nearly 70% of Alpine trees are sick or dying from pollution and the development of infrastructure, mostly attributed to mass tourism. Farming communities of the seven Alpine countries, Liechtenstein, Switzerland, Italy, Austria, France, Slovenia and Germany, have been victim to the gradual loss of high pastures, as governments have allowed further development of ski resorts, which for the short-term are more profitable than farming land. Zillertal, Austria is just one example of mass tourism's degradation of the Alps. During the peak ski season in Zillertal, more than 20,500 cars per day use the one road that climbs up a narrow valley into the skiing villages. In 1990, Zillertal housed 160 ski lifts and cable railways to sustain the influx of tourists. Large high-altitude skiing resorts housing 10,000 hotel beds now dot French Alpine areas.
In some of the larger African game parks, 20-30 vehicles may park around one pride of lions. The character of such parks and their viability as environments for some species is threatened by the volume and behaviour of tourists and the construction of tourist facilities.
Boracay, a jewel island in the Philippine archipelago, was once reputed to be the world's most perfect beach with fine, sugar white sand. No more. The turquoise waters around the butterfly-shaped islet are cloudy, and green algae lap at the shore. Islanders say this is due to seepage of used water and solid waste from the 30,000 tourists a day who visit during peak season.
The "Jessica" oil spill that polluted the waters and coastline of the Galapagos Islands in 2000 was oil destined largely for tourist use, the result of the large rise in ecotourism in this region of exceptional biodiversity.