3. Negative tourism impacts

Overcrowding, misuse of natural resources, the construction of buildings and infrastructure, and other activities associated with tourism, produce impacts on the environment. These impacts may be not only physical, but also cultural. In this chapter the most frequent and damaging tourism impacts at local level in regard to protected areas are analysed.

In general, the impacts of tourism vary according to the number and nature of tourists and the characteristics of the site. The individual tourist normally has a relatively small impact. Problems arise, however, if the number of tourists is large or the resource overused. Thus although tourism can be a lucrative source of revenue for a protected area, it can also represent a major management problem. As with most problems, the negative impacts of tourism can only be managed effectively if they have been identified, measured and evaluated. Once this has been done, tailored management responses can be created.

Tourism impacts on protected areas can be broadly classified in two categories: direct and indirect. Direct impact is caused by the presence of tourists, indirect impact by the infrastructure created in connection with tourism activities.

For the purposes of this book, direct tourism impacts on the environment have been classified as follows:

These impacts (which are actually manifestations of change) are dealt with below, one by one. But it should be remembered that the ecological effects of tourism activities rarely occur singly.

Impacts which are likely to occur together, or to follow in sequence, can be predicted to some extent. Sites of more intense recreational activity will be the first parts of an area to be affected, and can be used to forecast changes likely to occur elsewhere in the event of increasing intensity of use or misuse.

For very ample discussions on tourism impacts in natural areas, see Kuss et al. (1990) and Speight (1973).

Impacts on geological properties, rock formations, minerals and fossils

Climbing and caving are the two activities that make most use of rock formations. But apart from minor abrasion of rock faces and the wearing away of surface travertine deposits, their effects appear to be negligible (Speight, 1973).

The collecting of minerals, rocks formations and fossils gives more cause for concern. One of the most dramatic examples of the effect of rock collecting is that of the Petrified Forest National Monument in Arizona. Souvenir hunters have totally stripped various sites of their fossil tree covering. Similarly, frost-net features in the Rocky Mountains National Parkland have been destroyed by visitors who have removed the stones that once outlined the frost polygons (Scott-Williams, 1967). In New Mexico, "rockhounding" has become so popular that the 100 hectare Rockland State Park in New Mexico has been set aside specifically for mineral collecting in order to relieve pressure in other areas (Mitchell, 1967).

In less developed countries, lack of surveillance contributes to fossil depletion. This is the case in the fossil area of San Juan Raya, Puebla, Mexico. Also, at many sites, the eagerness with which cave formations such as stalactites are sought has made the use of elaborate protection devices necessary.

Governments now realize that national parks and protected areas safeguard the natural environment and the cultural heritage of their countries. The Dryandra State Forest Reserve, Western Australia, preserves eucalyptus forests that host the endangered numbat (an endemic marsupial) (25); Portobello World Heritage Site, Panama, protects the remains of Spanish colonial fortifications (26); and Chichén Itzá Archeological Zone (a World Heritage Site) in Yucatán, Mexico, contains magnificent Maya ruins, surrounded by undisturbed deciduous forest (27).

Impacts on soils

Terrestrial and aquatic soils are treated here together, along with beach sands and estuarine muds, cave earths and screes.

Impacts on soils may be of several kinds. Soil removal and relocation is due mainly to the introduction of on-site facilities or site management, and can in effect "sterilize" land by burying its surface under buildings or car parks.

Soil creep, slides and scree movement can occur as a result of walking activity. Soil creep becomes noticeable when it results in terracette formation, which often accompanies the development of hillside contour or oblique paths, as seen in areas used for hiking and pony-trekking. A more dispersed downward movement of topsoil can be caused by visitors when they walk or scramble down a slope. Slopes of volcanoes of recent origin are particularly vulnerable. (Careless scrambling prevents natural vegetational succession). In a dense temperate woodland with an unconsolidated chalk-rubble-soil, unstabilized by ground vegetation, the average rate of downslope movement has been found to increase from 5 cm/year to 30 cm/year as a result of such activity. Use of paths can be sufficient to reactivate screes, that would otherwise be stabilized by ground vegetation.

Soil break-up due to the "powdering" of litter layers usually occurs on paths or tracks, and sometimes also over wider areas such as camp-sites. Disappearance of the soil litter layers due to fragmentation (and subsequent leaching/erosion) is one of the processes that usually occurs during the initial stages of path formation. (Many paths are simply strips of exposed soil.) It was found that the volume of leaf litter on a newly-opened temperate woodland nature trail, used by 8,000 people, decreased by 50% during the course of a single week. Conversely, grass litter increased in depth, reflecting the decline in ground vegetation. It has also been observed that the powder produced by the comminution of woodland leaf litter is dispersed by wind erosion. A similar phenomenon has been observed along trails and near car parks, in a peaty montane soil. Horses' hooves can also break up trail surfaces. Continued loss of soil litter layers is very detrimental to an ecosystem because it decreases nutrient recycling and reduces the populations of those organisms that carry out recycling processes (Kuss et al., 1990).

Soil compaction is caused mainly by trampling. It has been observed on chalk grassland, in caves, along lake shores, and on paths and tracks. It has also occurred as a result of compression — due to trampling — of the surface of frost polygons. Path compaction due to the passage of horses has also been noted (Kuss et al., 1990). Soil compaction is sometimes exacerbated by the passage of vehicles — for example on camping grounds. (Dunes too are vulnerable to the trampling of visitors and the passage of vehicles.) Indeed, most references consulted by Speight (1973) concern "camping" in woodlands. This may be an artifact of the disproportionate interest in campground management on the part of the US Forest Service in particular, but an alternative explanation is that camping is the recreational activity most likely to cause soil compaction and that woodland sites are the most susceptible. (A survey of 137 forest campgrounds in the USA found that 70% of them were suffering from compaction.) The facts are obscured by the use made of the word "camping" in American literature on compaction. "Camping" is used as an umbrella term to refer to anything from the simplest tent to the most complex mobile home.

Compacted soils may not always be reliably identified by eye; compaction recorded for a chalk grassland soil after the passage of 8,000 people was found to have disappeared after two week's respite. Evidently, continuous trampling reduces the ability of the soil to recover, due to the decrease in abundance of active roots.

Consequences of compaction include impeded drainage (which leads to increased run-off and erosion), decreased water and air availability to plant roots and soil organisms (causing alteration in soil organism populations and plant death), and decreased abundance of larger pore spaces (leading in turn to a decline in the populations of larger soil organisms). Present information on soil compaction is not sufficiently precise to allow prediction of damage resulting from given intensities and types of use. But it is known that compacted, puddled and churned-up soil surfaces increase surface run-off.

Puddling of the ground surface of trails used for horse riding can also impede drainage and result in the development of marshy surface conditions. (Puddling leads to "gleying" and other drainage problems and simultaneously destroys plant roots that would otherwise help re-establish vegetation cover.) Additionally, any facility with areas of impenetrable surface, such as roof-tops, hard-topped paths and areas of hard standing, will be susceptible to surface run-off. However, it is only areas of intense recreational activity, such as picnic sites and trails, that appear to be affected by significant changes in run-off and drainage. Texture of ground surface (e.g. covered with vegetation or bare), angle of slope, soil type (sands are less susceptible to drainage changes than finer-grained soils), initial drainage patterns and intensity of use can all influence run-off and drainage changes. Erosion is the most likely consequence of increased run-off.

Soil erosion at picnic sites, on paths and among sand-dunes is often attributed to the impact of recreational activities. But recreational activities are themselves almost never agents of erosion, their effect being only to provide circumstances in which forces of erosion, i.e. wind and water, are more likely to occur. Decrease in ground vegetation and increased soil compaction (which often occur together) are two commonly recorded impacts of recreational activities that can accelerate erosion. Wind erosion is liable to affect peaty or sandy soils, especially when they are dry, but erosion is principally the result of water action. Sand-dune systems are notoriously vulnerable to wind erosion once their vegetation cover has been broken.

In Gunung Gede Pangrango National Park (West Java, Indonesia) soil erosion is particularly conspicuous. It is mainly attributable to the large numbers of visitors per location per period, poor management, lack of appropriate recreational facilities, and lack of visitor awareness concerning nature conservation. Physical factors i.e. high annual rainfall, the steepness and the length of slopes, are also contributory factors. Soil erosion is particularly noticeable on the trails leading to the park's summit and other peaks, and is a result of off-track walking and the large numbers of people who take short cuts, leading to the widening and deepening of existing tracks. Soil compaction around camping sites is, however, insignificant since most of the camp sites have stony soils (Supriadi and Darusman, 1992).

Wind and water may act together as agents of erosion. Soil erosion by water is usually dependent on surface run-off and usually most serious on hill-sides in high rainfall areas. Once eroding surfaces have developed, soil erosion is likely to continue and spread laterally, either until bedrock is exposed, or until the water-table has been reached. The water-table level in effect reduces wind erosion, producing stable dune slacks in dune systems. Gully erosion more or less ceases once the bed-rock has been exposed, unless this is itself susceptible to erosion. If hill soils are thin, gullies usually develop to a shallow depth only.

Since an in-situ soil may take up to 12,000 years to develop, soil erosion can lead to permanent ecological change (Speight, 1973). The eroded material is often redeposited elsewhere. This eroded material can make large outwash fans at the down-slope end of gullies, or become drifting dunes of windblown sand. In either case, deposited material can quickly bury vegetation, producing new areas of bare ground that also erode. Bare ground produced in this way can occupy an area similar in extent to that bared by the original erosion. Bank erosion of rivers, produced by the wash from pleasure craft, particularly high-speed motor boats, has also been recorded, but no quantitative information is available.

Successful management of protected areas calls for the active involvement of park rangers and local people in the ecotourism process, as these examples show: park rangers of the Delta du Saloum National Park, Senegal, provide tips on where to observe birds (28); a ranger at Punta Tombo Nature Reserve, Patagonia, Argentina, explains to tourists that an oil spill is responsible for the death of a Magellanic penguin (29); a park ranger with his hospitable family at Popenguine Faunal Reserve, Senegal (30).

Little is known of the effects of tourism activities on aquatic soils, although it has been suggested that in shallow, slow-moving water the stirring action caused by the passage of pleasure craft (particularly those with propellers) may prevent sedimentation. It is also possible that the mooring of boats in a previously undisturbed area can alter sedimentation patterns by allowing deposition of finer-grained material.

Soil enrichment or eutrophication often occurs as a result of the organic litter, mainly food, left behind by tourists. Faeces and urine from humans, and accompanying dogs or horses, are an additional source of organic waste. (A ratio of one dog to twenty people has been recorded for day visitors to the Peak District National Park in England (Speight, 1973).) An increase in nutrient-demanding ground flora (various grasses) on sites experiencing a high intensity of recreational use has been observed, as well as an increased nutrient status due to the deposit of animal faeces. Recreational activities may also lead to a changed dispersal of soil nutrients, e.g. as a result of the use of fallen timber as fuel wood for camp-fires.

The effects of tourism on soil organisms are not well understood, but are presumably associated with processes such as erosion, compaction and eutrophication. Some of the effects of trampling upon soil arthropods have been observed. Compaction causes species composition to change since it progressively "excludes" larger species. Paths are certainly susceptible to this. In a chalk grassland area it was observed that a decrease in the number of earthworms and in the abundance and diversity of soil arthropods corresponded to increasing intensity of recreational activity. Similarly, an examination of bacterial populations in trampled (compacted) and untrampled woodland soils near Zurich, in Switzerland, established that bacteria in trampled soils were only half as abundant as in untrampled soils (Kuss et al., 1990).

Alpine soils provide additional examples of adverse impacts resulting from unsustainable tourism. In the alpine zone of the Mt Everest region, the continual loss of groundcover and protective A horizons on the thin morainal soils has been linked to the harvesting of juniper shrub species for fuelwood, and to the mining of alpine turf for lodge and wall construction. These processes are in turn exacerbated by soil disturbances caused by grazing cattle. Consequently, the protective monsoon increases in herbaceous groundcover are less in these areas. Alpine regions may thus exhibit substantially higher rates of soil loss than do the much-publicized forests and shrub-grasslands, even though their annual precipitation is lower and less intense (Byers et al., 1992).

Impacts on water resources

The management of tourism impacts on water resources has received comparatively little attention from the scientific community, other than from a public health standpoint. However, land-use planning in relation to water quality and point and non-point sources of pollutants, and to methods of managing eutrophic recreational waters, is frequently mentioned in literature concerning recreation.

Managing water quality involves dealing with water flow, surface storage, and ground water systems. Groundwater systems may serve as municipal, domestic and park water supplies, and, in the case of surface waters, as recreational amenities and resources.

Since water resources recognize no jurisdictional boundaries, national protected area authorities should monitor not only those activities that take place within the protected area, but also those that occur outside it. This is because land uses external to protected area units can seriously degrade the quality of water resources within them, as in the case of logging outside Redwood National Park in the USA.

The capacity of each water resource for serving recreational interests will vary, but generally the greater the number of people using an area at any one time, the greater the risk of a decline in water quality. Some activities are potentially more damaging than others. Use of motorboats in particular can lead to beach and shoreline erosion, dissemination of aquatic weed nuisances, chemical contamination, and turbulence and turbidity in shallow waters (Kuss et al., 1990).

In rivers and streams, flow, dilution and dispersion generally mean that pollution impacts are localized and temporary. They will be more persistent, however, if they are the result of a continuous emission of waste into the upstream reaches outside the protected area or if use of water resources is concentrated, frequent, and combined with inadequate or improperly sited waste disposal facilities.

Oligotrophic waters are especially sensitive to the introduction of human wastes that enrich a very low natural background nutrient load. This is particularly true if waste is continuously rather than intermittently deposited. Impacts may be temporary and seasonally influenced in areas of intense use. Since viable fecal bacteria have been shown to persist in sediments at much higher concentrations than in the water column, areas subject to intense use may present health hazards if the sediments are disturbed or dispersed. Nutrient enrichment and bacterial contamination problems are also common in areas in which construction is permitted, and inholdings developed with cottage, camp, or trailer facilities served by improperly-sited sewage disposal systems.

Proper siting of designated camping areas in terms of soil suitability and distances to water resources are management responsibilities important to water quality management. Periodic sampling of the water composition is recommended in areas receiving high use in the watersheds or on the water. Of particular concern is the rising incidence of Giardiasis and its debilitating effects on humans infected by the disease-causing parasite. This problem is likely to increase due to a high frequency of human carriers attracted to park environments and the ubiquity of animal carriers (Kuss et al., 1990).

Excessive growth of algae is another water management problem and frequently observable in recreational inland waters enriched with sewage effluents. Unfortunately, the most common means of sewage treatment is not sufficient to remove the nutrients that stimulate plant growth. Nutrient-rich discharges into enclosed water bodies can stimulate algal growth to the point where recreational activities are seriously disrupted. Strands of filamentous algae, for example, merge together to form dense floating masses on the water surface, preventing recreational activities such as swimming and boating.

Coastal and marine waters are very susceptible to tourism impacts. The adverse effects of sewage and waste-water disposal from beach hotels are widespread. Many hotels use chemicals (such as chlorine or caustic soda) to disperse the odour of sewage, or to dissolve fats and oils. These chemicals are toxic and harm marine life. Some hotels also discharge chlorinated swimming pool water into the sea.

Of course, impacts on coastal ecosystems are not caused only by tourism activity. There are many other agents, which obviously may affect tourism activities, such as: industrial and agricultural pollution; siltation from eroded uplands; filling to provide sites for industry, housing, airports and farmland; dredging to create, deepen and improve harbours; quarrying; and the excessive cutting of mangroves for fuel.

Certain types of marine and coastal habitats are particularly vulnerable to development pressures. The less visually attractive habitats, such as mangroves and marshes, are often used for resort construction. As visitors inevitably want a view of the sea and easy access to the beach, hotels are often sited too close to the tideline, altering natural sand movement and accretion and frequently causing serious erosion. Airports, as essential as hotels to certain segments of the tourist industry, need large areas of flat land, often in short supply on islands, and so reef flats are reclaimed - the construction work often causing siltation and damage to adjacent reefs. Building materials are in short supply on small islands, and corals provide the easiest and in the short term the most economical source.

Box 7: Impact of tourism vehicles on wildlife in Maasai Mara National Reserve, Kenya

A study on the impact of tourism vehicles on three target species (cheetah, leopard and lion) in the Maasai Mara Reserve in Kenya was carried out in 1990. The responses of the animals towards vehicles and tourists were recorded. These included walking or running away from a vehicle, observation of vehicles, and hiding. Cheetah and lion in the unvisited areas exhibited a "high response" to vehicles, compared to those in visited areas. It was not uncommon for animals in undisturbed (not visited) areas to flee vehicles immediately after having sighted them. No leopards were sighted in the areas not frequented by visitors.

In the case of cheetah, the time allocated to feeding varied greatly between areas visited and areas not visited. In the areas without visitors, feeding activities were mainly carried out in the morning and late hours of the day. For cheetah observed in visited areas, little feeding activity took place during the peak game drive hours, but increased when visitors returned to the lodges for lunch and afternoon rest. Thus peak feeding time was at mid-day. For lions, the time allocated to feeding was very similar no matter what the area, the exception being the early part of the morning and late evening when feeding activity was greater in the areas without visitors. Interference with feeding is of particular concern with regard to cheetah, since they are diurnal hunters. For lions, vehicle interference may not be critical since they are mostly nocturnal hunters.

Vehicles usually congregate around sighted animals. For the cheetah, an increase in the number of vehicles coincided with a decrease in walking activity and vice versa. Lions did not respond greatly to vehicle numbers. Leopards were usually perched in trees, but if on the ground, they immediately walked off into hiding if a vehicle appeared.

In order to obtain a better view for photography, drivers usually vie for position around the animals which can lead to a high degree of encirclement. The angle (arc) of encirclement is a measure of the vehicles surrounding an animal and it varied from 90° to 360°. Generally, results showed that an increase in encirclement leads to increased levels of walking for both cheetah and lion, particularly between 90° and 270°. At less than 270° there was still room for escape, but at 360° escape was extremely difficult.

Most of the animals walked off when they were too closely approached. For the three species studied, distances under five metres appeared to be the most critical. At greater distances the animals did not seem to be greatly disturbed. However, at distances exceeding 21 metres, the cheetah walked off. This was probably vehicle avoidance behaviour.

In conclusion, it is evident that vehicles were interfering with the animals' activities, and their mobility in particular. Restricted movement can also interfere with other activities such as searching for prey, mating and seeking cover. All these factors affect the survival of the three target species. For that reason, the reserve management should seek to prevent encirclement by vehicles, and the habit of approaching the animals too closely. It should also control the number of vehicles present in the reserve at any one time and ensure that vehicles are distributed evenly in the reserve, both in time and space.

Source: Adapted from Muthee, 1992, in Gakahu, 1992b.

Impacts on vegetation

Recreational activities can have an immediate, direct impact on the species composition of vegetation. This is especially true of ground layer vegetation, and particularly as a result of trampling. Almost invariably this involves a decrease in species diversity. Plant-picking and uprooting by plant collectors and casual flower-pickers can also lead to loss of individual species. Generally speaking, damage produced by trampling is greater than that caused by camping.

Passage of tourism vehicles has also been observed to have adverse effects on vegetation. In the Maasai Mara reserve in Kenya, drivers of tourism vehicles often leave designated tracks and criss-cross the grasslands in search of the elusive predators. This has led to localized degradation of the grass and development of multiple tracks. These have in turn destroyed the naturalness of the areas affected. Studies have shown that an increase in vehicle passage resulted in increased loss of vegetation cover on the parallel strips (wheel-tracks) and turning radii loops (Muthee, 1992, in Gakahu, 1992b). In both the wet and dry seasons more damage occurred along the turning radii loops. The passage of tourism vehicles had also affected the species composition of vegetation cover. The following measures have been recommended:

Recreational activities can also affect dead (standing or fallen) tree trunks and branches. The most common use of fallen dead wood is as fuelwood for camp-fires. A study of a campsite in the UK, located near a closed-canopy ancient woodland, found that the quantity of small timber had declined significantly. This was noticeable up to 100 metres from the side of the road. Those responsible were probably people camping in tents, rather than people in caravans who seemed less inclined to light camp-fires.

It is important to recognize that the making of trails obliterates ground-covering vegetation, among other things, due to the usual application of inert material on trail surfaces, to avoid washout, muddying and excessive erosion. For that reason, it is wise to reduce to a minimum the number of trails in a protected area, and also to ensure that visitors remain on the trails. Excessive pedestrian traffic which overexposes trailside tree roots should also be avoided.

Use of off-road vehicles should be discouraged in all protected areas, since the damage they cause to ground vegetation is enormous. Extreme caution should also be applied in the lighting up and extinguishing of campfires, in order to avoid burning of the native vegetation. Camping in non-designated areas is more damaging than concentrating this activity in clearly specified sites.

It should be strictly forbidden to build tourism facilities in areas of native vegetation. Only areas that have previously been cleared (for farming, etc.) or that are characterised by heavily disturbed, second growth vegetation should be used as building sites.

Impacts on wildlife and ecosystems

The most extreme effects of tourism on wildlife arise from hunting, shooting and fishing, all of which may severely deplete local populations of certain species. But it is also well established that the mere presence of people can be sufficient to disrupt the activities of wild animals (particularly birds and large mammals) whatever the recreational activity or number of people involved. A survey of the breeding status of the little tern (Sterna albifrons) in Britain provides a number of instances of breeding failure of the species, apparently caused simply by the presence of fishermen and bathers on nesting beaches (Speight, 1973).

In some instances, disturbance may be caused more by the equipment people use in association with recreational activities, than by the people themselves. Noise, for example, produced by portable radios and the engines of motorboats and motor vehicles can be extremely alarming for animals. And various forms of pleasure craft can affect bird life merely by their presence. Motorboats and sailing craft can also disturb waterfowl in deeper water, especially during those periods when some of these birds are flightless. Bird species that build floating nests on inland waters, such as the great crested grebe (Podiceps cristatus), are likewise easily affected by motor boats and water-skiers.

Some waterfowl — particularly nesting waterfowl — are agitated by punts, canoes and rowing boats. This is because the latter have a shallow draught and can approach closer to the water's edge. Disturbance of waterfowl may even cause these birds to desert water-bodies that they used to frequent. Tourists taking boat rides in the Celestún area of the Yucatán Peninsula in Mexico cause much disturbance to the enormous concentrations of flamingoes (Phoenicopterus ruber) that winter here. (Boat operators should maintain a minimum distance of 200 metres between their boats and the flocks (Ceballos-Lascuráin, 1989)). Boating activities may affect fish populations too, particularly as a result of oil spillage or due to noise.

Many species of bird are vulnerable to the impacts of tourism. Examples include the common noddy and sooty tern, which breed communally on beaches and are frequently disturbed by bathers, but are protected in places such as Michaelmas Cay in the Great Barrier Reef Marine Park in Australia (31); and the Magellanic penguin, which nests on the southern coasts of Argentina and is very vulnerable to disturbance by beachcombers and to oilspills, but is strictly protected in Punta Tombo Reserve (32).

Impacts on animal life in protected areas are highly diversified. In Kenya's Amboseli National Park, for example, the number of tourist vehicles which approach target species such as lions is monitored to avoid perturbing the animals (33). Strict controls seek to prevent disturbance of wildlife by tourists in these protected areas of Latin America: the Monarch Butterfly Sanctuary in Mexico, where millions of these migratory insects spend the winter (34); and Hood Island, Galápagos National Park, Ecuador, where seals breed (35).

Some bird species are of course much less sensitive to human presence. For example, evidence suggests that breeding success among the red grouse (Lagopus lagopus) and ptarmigan (Lagopus mutus) on ski slopes, is not affected by people using the cable cars or walking through the area (Watson, 1970). Similarly, on the Galápagos Islands, tourists walk amidst nesting seabirds to no (apparent) ill effect. However, the blundering of uninformed walkers, picnickers, or fishermen, will disrupt the breeding activities of many bird species and also, for example, of turtles. Such situations may be aggravated if people wear brightly coloured clothing.

Many mammal and bird species will alter their behaviour patterns if disturbance becomes severe. For instance, deer and chamois may avoid areas frequented by people during the day. In general, animals of open habitats are those that are most susceptible to human presence. There are indications that, for some species at least, it is frequency of human presence, rather than the number of people present at any one time, that is the most important factor.

Consumption of wildlife by tourists can be harmful to local populations of that wildlife if not controlled. For instance, demand for sea food by tourists can have a severe impact on local fisheries and threaten wildlife populations within protected areas. Spiny lobster and conch populations are now much reduced in the Caribbean, and consequently luxury foods in many places, consumed in hotels rather than as a staple by local people. Tourism has also been largely responsible for the enormous increase in the marine curio trade. Corals and shells are sold in resorts throughout the world, and often poached from marine parks. Tortoiseshell is still popular, although its sale is illegal in most countries (Thorsell and Wells, 1991).

Other species benefit from tourism activities, but often to the detriment of rarer species. Organic litter left at campsites and picnic areas is "collected" by scavenging species. There are many examples of this, especially in temperate countries. Observed long-term effects of tourist litter include:

Habitat changes and population localization of the brown and grizzly bears attracted by picnic rubbish in US national parks, and migrations of wild boar during the winter into areas of Belgium where they had not previously been seen, due to increased availability of camp-site rubbish have also been observed (Speight, 1973).

But although many animal species are directly affected by outdoor recreational activities, many more are affected indirectly by alterations in their habitat. For instance, if a ground flora is eradicated by trampling, insects dependent upon that ground flora will also disappear. Likewise, if a flooded gravel pit is planted with marsh vegetation for the benefit of wild-fowling interests, not only wildfowl but also a host of other vertebrate and invertebrate species will colonize the habitats that develop, possibly displacing species that formerly inhabited the area.

The environmental impacts of tourism on coral reefs have been well documented, especially in the Great Barrier Reef Marine Park, Australia (36).

Some ecosystems and habitats are particularly vulnerable to development pressures. This applies especially to marine ecosystems and habitats since these are often the foci of tourism activity. For instance, less visually attractive habitats such as mangroves and marshes, are often drained and used for resort construction. And since visitors generally want a view of the sea and easy access to the beach, hotels tend to be sited close to the tideline. This can result in changes in natural sand movement, and accretion, and lead to serious erosion. Other activities that are often associated with tourism development, such as coast stabilization, causeway construction and mariculture development, can also have severe negative impacts.

The environmental tourism impacts on coral reefs have been particularly well documented (Craik, 1992; Driml, 1987; Kelleher, 1991; Salm and Clark, 1984; Schoorl and Visser, 1991; Woodley, 1992). In general, impacts on coral reefs fall into one of three categories:

Structural damage occurs when, for example, reef flats adjacent to coral reefs are used for the construction of landing strips, and results in siltation.

Moreover, on small islands, the building materials for such construction are often in short supply and coral reefs therefore perceived as offering the most readily obtainable and cheapest substitute.

Process damage involves impacts on ecosystems through alteration of some physical, chemical or biological factor. Physical factors generally concern changes to current patterns, levels of silt, or flow of fresh water into the marine environment. Chemical problems may arise due to the downstream effects of pesticide or fertiliser runoff and biological damage can occur when processes that maintain diverse or distinctive communities are disrupted.

The natural qualities of a site provide amenity value for people. Thus overuse of a coral reef site or a change in type of use (e.g. from low-key recreation to mass tourism) can alter its amenity value.

Impacts on coral reefs from tourism activities also include the "on-off" effects from building or installation of structures such as jetties, moorings, marinas, underwater observatories, resorts and their support facilities (such as sewage, power or water supply). In Australia, the impacts that most concern the Great Barrier Reef Marine Park Authority (GBRMPA) include smothering and reduced light penetration due to increased sediment load, changes in water quality due to increased nutrient levels, physical damage due to the use of machinery and explosives, pollution due to spillage of fuel and oil, and changes in amenity value (for both local communities and visitors). Thus the monitoring of tourism impacts in the GBRMP is primarily concerned with unintended biophysical and social effects (Woodley, 1992).

Box 8: Environmental impact of tourism on protected areas in Bahia, Brazil

Tourism is believed to be the fourth largest single source of income in Brazil and the third in the state of Bahia (north-east Brazil). It is estimated that tourism revenue amounts to approximately US$90 million per annum, and provides jobs for about 15,000 people. Protected areas are among the most attractive sites in Bahia but they have been suffering increasing levels of environmental damage due to increasing numbers of visitors. And as the state's environmental legislation does not fully tackle the issue of conservation of protected areas, over-use of sites is occurring. Thus the benefits that tourism brings in terms of income are negated by the environmental damage resulting from over-visitation.

In 1990, the depletion of certain animal populations had risen by 12%, compared to 1985 figures — mostly a consequence of the trade in animal skins. (Many of the skins were from animals in protected areas). In addition, some species found in protected areas are sought by visitors as "exotic" meals. Hunting is a popular activity in the state and commonly occurs in protected areas, despite being illegal. A source of income for local inhabitants, it is stimulated by the great demand of tourists for skins of rare species. Since Bahia is a very large state, effective monitoring and surveillance of hunting are difficult. To make matters worse, no effective means exist for either registering or retrieving information on the numbers of illegal skins that are confiscated. Moreover, the price for which animal skins can be sold is high when compared to local wages.

But it is not only animals that suffer from the pressure of trade. The depletion of populations of some protected plant species is also increasing — a result of the ready access to preserved sites. In protected areas, personal vehicles loaded with flowers and ornamental plants are a common sight. It is widely known that many orchid species found in Diamantina National Park are traded. Founded in 1985 by a presidential decree, but without prior consultation with the local communities, the park came to be seen as an attempt to restrict use of the region's natural resources. Before the park was formally designated, inhabitants from various parts of the state of Bahia visited the area and collected as many plants as they could. Orchids were particularly affected, since a considerable number of specimens were removed all at once.

Suggested actions to reduce the negative impacts of tourism in Bahia include:

Such strategies could be introduced not only in Bahia, but throughout Brazil to help ensure the continued existence of the flora and fauna of the country's protected areas.

Source: Adapted from Leal Filho, 1992

Not surprisingly, available information suggests that increasing intensity of recreational use of natural areas exerts its most profound effects on microhabitats, by causing a progressive simplification of vegetation, ground surface and soil structure. In other words, a proportion of the existing habitats is lost but not replaced by new habitats. This in turn leads to an overall decrease in species diversity in all trophic groups, in all parts of the ecosystem affected. Species associated with ephemeral habitats, such as bare ground, can be expected to maintain their numbers or even increase in abundance at the expense of species associated with more stable ecosystem conditions such as forest or woodland.

Some ecosystem components are more vulnerable to this simplifying process than others; ground vegetation, rotten wood and soil litter layers are affected the most severely of all. Camping, walking, and picnicking activities cause the most harm. Alterations in the composition of soil faunas may have far-reaching effects on soil type and soil process since they have considerable influence on the flow of organic materials and minerals.

Impacts on sanitation systems

The litter and human waste left behind by tourists create a sanitation problem in many protected areas, which can affect local populations.

Fig. 5: Ecological impacts of tourism.

Source: Adapted from Kuss et al., 1990).

Garbage seriously affects the sanitation aspects of natural bodies of water (both surface and subterranean), as well as soil, vegetation, cultivation, and the air we breathe.

It is important to separate organic from inorganic waste. Organic waste may be processed and turned into compost (an excellent fertilizer for parks and gardens). As regards inorganic waste, it is important to warn tourists against throwing away film and cigarette wrappings, beer cans, plastic cups and other containers, etc. (in some parks it is customary to provide visitors with small litter bags, but these should be made of paper, not plastic). The use of returnable bottles and other containers should be universally encouraged, by means of a deposit fee to be recovered when returning the item.

There is no completely safe method of waste disposal. All forms of disposal have negative impacts on the environment, public health, and local economies. Landfills frequently contaminate drinking water. Garbage burned in incinerators has poisoned air, soil, and water. Many water and wastewater treatment systems change the local ecology. Most attempts to control or manage wastes after they are produced fail to eliminate environmental impacts.

The only way to truly avoid environmental harm from waste is to prevent its generation. Pollution prevention means changing the way activities are conducted and eliminating the source of the problem. It does not mean doing without, but doing differently. Preventing waste pollution from litter caused by disposable beverage containers does not mean doing without beverages; it just means using refillable bottles.

Water from conventional treatment systems is usually disinfected with chlorine or chlorine compounds before being released back into the environment or reused. A side effect of this is that the chlorine or chlorine compounds are very reactive and sometimes produce highly persistent, toxic chemicals. Many environmentalists believe that there is no justification for use of chlorine for disinfection, and that other disinfectants should be used. The purpose of disinfection is to ensure that no virulent organisms are present after the water has been processed. Some alternative disinfectants are ozone and ultraviolet light. (National Park Service, 1993).

Waste prevention leads to thinking about materials in terms of reduce, reuse and recycle. The best way to prevent pollution is not to use materials that become waste problems. When such materials must be used, they should be reused on site. Materials that cannot be directly reused should be recycled.

All people associated with a tourist facility must change their habits and adopt a more responsible attitude towards sanitation. This includes the ownership and management of the facility, as well as the designers, contractors, employees, and visitors.

Box 9: The impacts of tourism in Antarctica

People have been visiting Antarctica for over 100 years but prior to the 1950s they were nearly all members of exploratory and/or scientific expeditions, and usually the beneficiaries of government sponsorship. Since then, more and more tourists have been travelling to Antarctica by sea and air. In 1969, Eric Lars Lindblad began using the M/V Lindblad Explorer, a custom-built 2,500-ton, reinforced, 100-passenger vessel, for Antarctic cruises. Currently, tourism in Antarctica involves over ten agencies, more than 30 cruises a year, and 5,000 tourists per annum.

Tourism is having an impact on the Antarctic environment as a result of the transportation it depends upon, the infrastructure it requires on land, and the activities of the tourists themselves. (However, many other activities, notably research, have had similar, and often more severe and prolonged impacts, and it is often difficult to distinguish these from those caused by tourism.)

Research into tourist impacts in Antarctica is just beginning. There are no previous or ongoing studies that allow researchers and managers to distinguish between natural variability in Antarctic animal populations and variability induced by tourism-related activities. Relatively long-term studies should be initiated to critically assess the effects of large tourist groups on Antarctic animal communities. They should compare coincident ecosystem variability at sites being visited by tourists with control sites from which tourists are being excluded.

However, although tourism is inflicting some detrimental impacts on Antarctica, it has promoted conservation efforts in the region. Lindblad believes that when managed properly, tourism can even save wildlife. Many of Lindblad's US passengers have apparently written to and put pressure on their congressmen to support the mineral rights issue

Under the Antarctic Treaty, member states have agreed to various general and specific guidelines for tourism. Indeed, IUCN's Strategy for Antarctic Conservation, advocates that the Antarctic Treaty and associated Recommendations should be modified so as to include more detailed guidelines on tourism in Antarctica.

It has also been recommended that countries with bases in Antarctica should publish policies, plans, and appropriate management practices for the conduct of tourism at these bases. Antarctic tourist orientation centres, similar to the one already operating in New Zealand, could be developed in Punta Arenas and Ushuaia, and included in tours to Antarctica.

Source: Adapted mainly from Marsh, 1992

The following waste prevention strategies should be generally applied:

In the Khumbu region of Nepal, the slower decomposition rates of human wastes at high altitude pose a special problem. Toilet paper littering continues, and water contamination is widespread. For the past 20 years, the burying of individual waste in "cat-holes" has been encouraged internationally as an appropriate and preferred backcountry practice. But this has resulted in the creation of "moonscapes" in the vicinity of the more popular camping sites (Byers, 1992).

Aesthetic impacts on the landscape

Irresponsible and/or uncontrolled tourism activity can have serious negative aesthetic impacts on the landscape that will undoubtedly mar the experience of the nature-loving tourist. The most common of these impacts are due to litter, particularly along roads or trails. In Gunung Gede Pangrango National Park in Indonesia, bottles, tin cans, paper and plastic bags, and excess food — all dropped by careless tourists — endanger the park's wildlife, and detract from the enjoyment of other, more thoughtful visitors (Supriadi and Darusman, 1992).

Littering is even worse in the Khumbu area of Nepal. In fact, Khumbu has long been cited as a representative model of contemporary landscape and environmental degradation in the High Himalaya. The trek from the Lukla airstrip to the Mt. Everest base camp has long been referred to as the "garbage" or "toilet paper" trail because of the quantities of refuse generated by trekking groups and individuals. But the canned goods packed in by expedition porters are perhaps of even greater concern than paper refuse. Empty tins are frequently deposited in makeshift dumps near villages and at lower altitude campsites. Additionally, above base camp, at the South Col, some 500 empty oxygen bottles have been dumped since the 1963 American Everest expedition (Byers et al., 1992).

Vandalism is another serious problem in many parks around the world. It occurs in many forms, including the painting of graffiti on boulders along nature trails, the cutting of tree bark, and destruction of fences and other physical facilities.

Other aesthetic issues dealing with inappropriate physical infrastructure, including road and trail design are dealt with in Chapter 7.

Two examples of vandalism by tourists in protected areas: cutting the bark of trees in Stirling Range National Park, Western Australia (37); and painting graffiti on boulders in Cascada de Basaseáchic National Park, Mexico (38).

Taking into account the impact on cultural features is vital in an area such as the Arán Valley in the eastern Pyrenees of Spain, where magnificent mountain scenery alternates with charming old villages and their Romanesque churches (39).

Impacts on the cultural environment

Many archaeological sites are found in protected natural areas. Indeed, on many occasions, it is the presence of a prehistoric or historic site that has led to designation of a protected area. And the site is often complemented by a natural ecosystem of interest. In other instances (particularly in Europe), the site is surrounded by intensively farmed land but possesses plant and animal species rare or absent elsewhere in the country. This is the case for the neolithic mound of Silbury Hill in Wiltshire, England (Speight, 1973). Many prehistoric sites are also of palaeoecological interest because of their ability to provide information concerning faunal and floral changes that occurred during the post-glacial, soil-forming eras. They also enable historians to describe the various land uses that were applied by early humankind.

Thus, disturbance of any archaeological site, particularly if soil erosion is involved, can result in the loss of irreplaceable information. Disturbance caused by amateur "pleasure" excavators, and collectors of exposed archaeological artifacts especially, is of growing concern. In the USA, specimen collecting on Indian sites has led to the recommendation that collection of artifacts should be prohibited, unless undertaken by specialized research personnel. Use of metal detectors for locating buried metal objects on archaeological sites is a further threat, and one that is already acute in some English counties (Speight, 1973).

Understandably, larger earthworks and other features such as cave-paintings act as foci of tourism activity. But unless well controlled, such activity can cause many problems. The "maladie verte" of the Lascaux cave-paintings in France is a good example. Within ten years of their being opened to public viewing in 1948, the caves were attracting 125,000 visitors a year. But the paintings quickly became obscured by an algal growth which thrived on the higher humidity, light and proteinaceous residues brought in by visitors. The principal protein source, on account of its pollen and bacterial content, was apparently human breath. The caves have been closed to the public since 1963, and will remain so until an acceptable method of preventing the algal growth has been found.

Likewise, in southern England, intense tourism activity at various earthworks has led to localized erosion. At one site, the banks of a Bronze Age earthwork have been exposed to trampling for many years. A number of paths have appeared across the banks, at least two of which have been eroded down to the level of the surrounding ground surface. Another path has developed along the entire length of the spine on the main bank. The banks are disfigured in consequence, and although infilling of the gaps has been attempted, this cannot make good the decrease in the archaeological value of the site (Speight, 1973). Elsewhere, damage arising from tourism is even more serious since, unlike some ecological damage, no amount of financial or technical resources can buy or make good the loss. This applies above all to cultural substance and identity.

As Greenwood (cited in Kutay, 1989) points out, all viable societies create traditions, accept elements from outside, invent rituals, and are constantly in the process of reinventing themselves, for both sacred and secular purposes. Tourism as an agent of change and development can have a major impact on this process. Some societies, such as the Maasai of Africa, reject tourism influences, while others, such as the Sherpa, attempt to embrace them within the confines of their own traditions. (One of the best documented instances of the cultural impacts of tourism on an indigenous people within a protected area, is that of the Sagarmatha National Park on the Sherpas (Stevens and Sherpa, 1992).) Still others will abandon their cultural roots altogether in the face of the changes that tourism brings.

Yet whatever the approach adopted by societies, the international culture that is becoming universal, due to such influences as television and multinational corporations, is spreading inexorably. Tourism is aiding and abetting its penetration into previously remote and isolated places. Whether this would happen anyway is a moot point (Wood, 1991). What is clear, is that cultures that are economically vulnerable and politically subordinated are those most at risk from cultural changes instigated or wrought by tourism.

The megalithic site of Delbi in Senegal has supernatural qualities for the population of the area. Visitors to such isolated places must respect local religious beliefs (40). Measuring the carrying capacity of protected areas requires careful consideration of tourism impacts on vegetation, whether xerophytic - as in El Vizcaino Biosphere Reserve, Baja California, Mexico (41) - or a rain forest, as in Tikal National Park, Guatemala (42).

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