Conservation is the optimum sustained use of natural resources; therefore, cave conservation must provide not only for the protection of the character, decoration and biota of caves, but also for the means whereby people might enjoy and understand the caves that are their heritage. A cave is a natural subterranean cavity into which a man can enter to a point where daylight cannot be seen. Caves are not only interesting physical entities that provide distinctive sensory and perceptual experiences and invoke a variety of responses, but they also provide unique opportunities for scientific study. Speleology is the study of caves, and in New Zealand it attracts workers from many disciplines of the universities and government research establishments.(omitted)