Page 233 - Fundamentals of Geomorphology

216 PROCESS AND FORM

Humans and caves
widely used for cheese-making and rope manufacture,
Humans have long used caves for shelter, defence, sanc- as in the entrance to Peak Cavern, Derbyshire, England.
tuaries, troglodytic settlements, a source of resources Kentucky bourbon from the Jack Daniels distillery relies
(water, food, guano, ore in mine-caves), and as spir- partly on cave spring water.
itual sites. In the last few hundred years, caves have Cave tourism started in the late eighteenth and early
been used for the mining of cave formations and guano nineteenth centuries in Europe, when candle lanterns
(especially during the American Civil War), for hydro- were used (e.g. Nicod 1998). Today, cave tourism is
electric power generation from cave streams and springs a growth industry: fibre-optic lights illuminate some
(inChina),forstorage,andassanatoriaandtouristattrac- caves, and electric trains transport tourists through the
tions. Evidence for the human occupancy of caves in caverns. Tourism has an injurious impact on caves
China dates from over 700,000 years ago. Many caves (Box 8.1). To combat the problems of cave tourism,
are known to have housed humans at the start of the last cave management has evolved and is prosecuted by a
glacialstage,andseveralhavewallsadornedwithsplendid body of government and private professionals. Several
paintings. Many caves in the Guilin tower karst, China, international groups are active in cave and karst man-
have walls at their entrances, suggesting that they were agement: the International Union of Speleology, the
defended. Medieval fortified caves are found in Switzer- International Speleology Heritage Association, the Inter-
land in the Grisons and Vallais. In Europe and the USA, national Geographical Union and the Commission for
somecaveswereusedassanatoriafortuberculosispatients National Parks and Protected Areas, and the Interna-
on the erroneous premise that the moist air and constant tional Union for the Conservation of Nature and Natural
temperature would aid recovery. Caves have also been Resources (IUCN).

Box 8.1

CAVE TOURISM

Some 20 million people visit caves every year. car parks and paths, or by including strips where infil-
Mammoth Cave in Kentucky, USA, alone has 2 million tration may occur. Within caves, paths and stairs may
visitors annually. Great Britain has some 20 show- alter the flow of water. Impermeable surfaces made of
caves, with the most-visited receiving over 500,000 concrete or steel may divert natural water movement
visitors every year. About 650 caves around the world away from flowstones or stream channels, so leading to
have lighting systems, and many others are used for the drying out of cave formations or to increased sed-
‘wild’ cave tours where visitors carry their own lamps. iment transport. These problems are in part overcome
Tourists damage caves and karst directly and indirectly by the use of permeable steel, wooden, or aluminium
through the infrastructure built for the tourists’ conve- walkways, frequent drains leading to sediment traps,
nience – car parking areas, entrance structures, paths, and small barriers to water movement that approximate
kiosks, toilets, and hotels. The infrastructure can lead the natural flow of water in caves.
to hydrological changes within the cave systems. Land Cave tourists alter the cave atmosphere by exhal-
surfaced with concrete or bitumen is far less permeable ing carbon dioxide in respiration, by their body
than natural karst, and the danger is that the feedwaters heat, and by the heat produced by cave lighting. A
for stalactites may be dramatically reduced or stopped. party of tourists may raise carbon dioxide levels in
Similarly, drains may alter water flow patterns and lead caves by 200 per cent or more. One person releases
to changes in speleothem deposition. Drainage prob- between 82 and 116 watts of heat, roughly equivalent
lems may be in part alleviated by using gravel-surfaced to a single incandescent light bulb, which may raise