Bats as flying, nocturnal animals occupy a unique ecological niche. Most of the cave dwelling bat species are insectivorous, and feed on nocturnal insects. They provide valuable ecological services to the environment and economic services to man. These services may extend over fairly large areas as many cave-dwelling species in Australia and Malaysia have been shown to travel considerable distances at night to forage. The diurnal (day-time) roost of bats is important since it offers protection from exposure to day-time ambient conditions and predators, promotes energy conservation, and facilitates social interactions.
Cave roost sites are a limited resource, since they are usually rare and unevenly distributed features of most landscapes. Caves often contain a high proportion of different bat species that move about seasonally, since different bat species select micro-climatic conditions to best suit the metabolic or physiological conditions required for the survival and reproduction of their species. Hence, the micro-climatic conditions are different for different species, and may also vary seasonally for some species, such that they need to change roosts in winter and summer. Bats species throughout the world are vulnerable to the destruction of their roosts, as well as disturbances while in them, and these issues are of real concern for long-term conservation of bat populations. When large numbers of individual bats are concentrated in a few specific roost sites, they are extremely vulnerable to risks of disturbance or roost destruction, since despite their small size, bats have low reproductive rates and long generation times and cannot sustain elevated rates of mortality or depressed levels of recruitment. Hence, the preservation and conservation of bat roosts, in particular cave roosts, is probably the most important issue in bat conservation, since the loss or disturbance of these sites may not only have detrimental consequences for the bat populations they support, but may also have knock on effects elsewhere in a landscape if no other roosts are available.